03rd International Conference on Permafrost - Preceedings 2 Volumes

PROCEEDINGS OF THE

THIRD INTERNATIONAL CONFERENCE ON PERMAFROST

JULY 10-13, 1978 EDMONTON, ALBERTA, CANADA

VOL. 2

SPONSORED BY THE NATIONAL RESEARCH COUNCIL OF CANADA

COMPTE RENDU DE LA TROISIEME CONFERENCE INTERNATIONALE

SUR LE PERGELISOL

10-13 JUILLET 1978 EDMONTON, ALBERTA, CANADA

VOL. 2

SOUS L’EGIDE DU CONSEIL NATIONAL DE RECHERCHES DU CANADA

TPYAbI

TPETbEh MEXAYHAPOAHOh KOHcPEPEHUHEI IIO MEP3JIOTOBJI,EHE’IK)

10- 13 MKIJ’IE 1978 rOAA I?.3,QMOHTOH, AJIbEiEPTA, KAHAAA

TOM 2

OPrAHM30BAHHOfi IIO MHHUHATHBE HAI_IHOHAJIbHOrO HCCJIEAOBATEJIbCKOFO COBETA KAHAAbI

NATIONAL KESEARCH COUNCII. OF CANADA CONSEIL NATIONAL DE RECHERCHES DU CANADA

OTTAWA. 1979

The papers appearing in this volume have been printed In the language as submitted.

Published under the sponsorship of the: NATIONAL RESEARCH COUNCIL OF CANADA

Copies obtainable from: The Executive Secretary Third International Conference on Permafrost c o National Research Council of Canada

Canada

PRICE: %35.00(Vols. I & 2)

d ttawa, Ontario KIA OR6

ISBN 0-660-50401-4 NRCC No 16529 Cat. No. NR-15-6 1978-2

Les memoires qui paraissent dans le prkscnt volume ont Ctd imprimts dans la langue tels que soumis.

CONSEIL NATIONAL DE RECHERCHES DU CANADA PubliC sous le parrainage du

On peut obtenir des exemplaires en s'adressant au SecrCtaire administratif TroisiZme conference internationale sur le pergtlisol a/s du Conseil national de recherches du Canada Canada

PKIX: $35.00 (vol. I et 2)

CNRC N" I6529 No de cat. NR- 15-6 1978-2

ISBN 0-660-50401-4

ii

TABLE OF CONTENTS

SPECIAL THEME PAPERS

J. R. Mackay, V. N. Konishchev and A. I. Popov GEOLOGIC CONTROLS OF THE ORIGIN, CHARACTERISTICS, AND DISTRIBUTION OF GROUND ICE ................................................................

P. I . Mel’nikov and O. N. Tolstikhin PERMAFROST-HYDROGEOLOGICAL REGIONALIZATION O F EASTERN SIBERIA (In Russian) ........................................................................

L. C. Bliss VEGETATION AND REVEGETATION WITHIN PERMAFROST TERRAIN

J . Brown and N. A. Grave PHYSICAL AND THERMAL DISTURBANCE AND PROTECTION OF PERMAFROST ..........................................................................................................

W. J. Scott, P. V. Sellmann and J. A. Hunter GEOPHYSICS IN THE STUDY OF PERMAFROST ................................................

S. S. Vyalov INTERACTION OF PERMAFROST AND STRUCTURES(In Russian) ............

N . A . Tsytovich, Ya. A. Kronik and G. F. Biyanov DESIGN, CONSTRUCTION AND PERFORMANCE OF EARTH DAMS ON PERMAFROST IN THE FAR NORTH (In Russian) ......................................

A. Liguori, J . A. Maple and C. E. Heuer THE DESIGN AND CONSTRUCTION OF THE ALYESKA PIPELINE ............

SUBMITTED PAPERS - PEOPLE’S REPUBLIC OF CHINA

Chen Hsaio-pai and Wu Tzu-wang EXPERIMENTAL RESEARCH ON THE PRINCIPAL MECHANICAL PROPERTIES OF FREEZING AND FROZEN SOILS IN CHINA (A Review) ..............................................................................................................

Research Group on Pile Foundations in Permafrost TESTING OF PILE FOUNDATIONS IN PERMAFROST AREAS ........................

Research Group on Experimental Roadbed Research EXPERIMENTAL ROADBED IN AN AREA WITH A THICK LAYER OF GROUND ICE ............................................................................................................

Cheng Kuo-tung, Tung Po-liang and Lo Hsueh-bo EXPERIMENTAL RESEARCH ON AN EMBANKMENT IN AN AREA WITH MASSIVE GROUND ICE ..................................................................................

ADDRESS AT CONFERENCE DINNER Robert F. Legget ................................................................................................................

OPENING PLENARY SESSION ......................................................................................................

CLOSING PLENARY SESSION ......................................................................................................

POSTER SESSIONS ............................................................................................................................

FILMS ....................................................................................................................................................

EXHIBITORS ........................................................................................................................................

LIST OF REGISTRANTS ..................................................................................................................

... 111

PAGE

1

19

31

51

93

117

137

151

159

179

187

199

223

230

237

240

242

244

247

PAGE

TABLE DES MATIERES

EXPOSES THEMATIQUES SPECIAUX

J. R. Mackay, V. N. Konishchev et A. I. Popov FACTEURS GEOLOGIQUES QUI COMMANDENT L’ORIGINE, LES CARACTERISTIQUES ET LA DISTRIBUTION DE LA GLACE DANS LE SOL (Texte en anglais) .......................................................................... 1

P. I. Mel’nikov et 0. N. Tolstikhin PERGELISOL - HYDROGEOLOGIQUE DE L’EST DE LA SIBERIE (Texte en russe) .................................................................................. 19

L. C. Bliss VEGETATION ET RESTAURATION DE LA COUVERTURE VEGETALE DU PERGELISOL (Texte en anglais) .................................................................... 3 1

J . Brown et N. A. Grave PERTURBATIONS THERMIQUES ET PHYSIQUES ET PROTECTION DU PERGELISOL (Texte en anglais) ............................................ 51

W. J. Scott, P. V. Sellmann et J. A. Hunter LA GEOPHYSIQUE ET L’ETUDE DU PERGELISOL (Texte an anglais) ...................................................... _ _ ............................................ 93

S . S. Vyalov INTERACTION ENTRE PERGELISOL ET STRUCTURES (Texte en russe) ........................................................................................................ 117

N. A. Tsytovich, Ya. A. Kronik et G . F. Biyanov CONCEPTION, CONSTRUCTION ET COMPORTEMENT DES BARRAGES EN TERRE ETABLIS DANS DES TERRAINS PERGELISOLES DU GRAND NORD (Texte en russe) ............................................................................ 137

A. Liguori, J. A. Maple et C. E. Heuer CONCEPTION ET CONSTRUCTION DE LOLEODUC ALYESKA (Texteen anglais) .................................................................................................... 151

EXPOSES PRESENTES - REPUBLIQUE POPULAIRE DE CHINE

Chen Hsaio-pai et Wu Tzu-wang RECHERCHE EXPERIMENTALE SUR LES PRINCIPALES PROPRIETES MECHANIQUES DES SOLS GELES ET SE CONGELANT EN CHINE - UNE ANALYSE (Texte en anglais) .................................................................................. 159

Groupe de recherche sur les fondations sur pieux dans le pergelisol ESSAIS DE FONDATTONS SUR PIEUX DANS DES REGIONS DE PERGRLISOL (Texte en anglais) ............................................................................ 179

Groupe de recherche experimentale sur les assiettes de routes ASSIETTE EXPERIMENTALE DANS UNE REGION A EPAISSE COUCHE DE GLACE DANS LE SOL (Texte en anglais) ...................................... 187

iv

A

PAGE

Cheng Kuo.tung. Tung Po-liang et Lo Hsueh-bo RECHERCHE E x p e r i m e n t a l e S U R UN REMBLAI DANS UNE REGION DE GLACE MASSIVE DANS LE SOL (Texte en anglais) ............ ........., .............................................................................. 199

ALLOCUTION LORS DU BANQUET DE LA CONFERENCE Robert F . Legget ................................................................................................................ 223

SEANCE PLENIERE D'OUVERTURE .......................................................................................... 230

SEANCE PLENIERE DE FERMETURE ........................................................................................ 237

SEANCES DE PLANCHES EXPLICATIVES ................................................................................ 240

FILMS .................................................................................................................................................... 242

EXPOSANTS ........................................................................................................................................ 244

L i s t e DES INSCRIPTIONS .............................................................................................................. 247

V

COUEPXAHNE

1. 3 7

1 5 1

1 5 9

1 7 9

PEYb HA OrjEAE AJrR YYACTHBKOB KOHQEPEHUMM

PodepT JIerreT ........................................ OTKPbITkiE KOBOEPEHIlBW /nneHapHoe 3acena~ae/ ............ JAKPbPTME KOHOEPEHUBB /nneHapHoe 3aceaa~ae/ . ........... TEMATBYECKME BbICTABKR ................................

PErRCTPAUMOHHHm CIIMCOK ...............................

1 8 7

199

2 2 3

2 30

2 3 7

2 4 0

2 4 2

2 4 4

2 4 7

vii

1

G E O L O G I C CONTROLS OF THE O R I G I N , C H A R A C T E R I S T I C S ,

A N D DISTRIBUTION OF GROUND I C E

J . R . Mackay', V . N . K o n i s h c h e v 2 a n d A . I . P o p o v 2

' U n 3 v e r s i t y o f B r i t i s h C o l u m b i a , C a n a d a Moscow S t a t e U n i v e r s i t y , U . S . S . R .

A B S T R A C T

T h e g e o l o g i c c o n t r o l s o f t h e o r i g i n , Xn C a n a d a . s t u d i e s h a v e s h o w n t h a t s o m e - c h a r a c t e r i s t i c s , a n d d i s t r i b u t i o n o f g r o u n d i c e i n t h e p e r m a f r o s t a r e a s o f t h e w o r l d a r e n u m e r o u s . T h e r e v i e w a u t h o r s a r e v e r y c o n s c i o u s o f t h e f a c t t h a t i n a b r i e f s u r - v e y of t h e m o r e t h a n 300 p a p e r s w h i c h h a v e b e e n p u b l i s h e d s i n c e 1 9 7 3 , i t i s o b v i o u s l y i m p o s s i b l e t o d i s c u s s a l l t o p i c s a n d t o d o j u s t i c e e v e n t o t h o s e t o p i c s w h i c h a r e d i s c u s s e d , T h e s e q u e n c e o f t o p i c s , i n t h i s s u m m a r y , a r e t h e s a m e a s f o r t h e l o n g - e r r e v i e w p a p e r w h i c h c o n t a i n s t h e b i b l i o - g r a p h i c r e f e r e n c e s o m i t t e d i n t h i s s u m m a r y .

F r o s t H e a v i n g a n d I c e L e n s i n g

Much a t t e n t i o n h a s b e e n g i v e n t o t h e t h e o r e t i c a l a s p e c t s o f i c e l e n s i n g , t h e p r o b l e m o f s i m u l t a n e o u s h e a t a n d m.ass t r a n s f e r i n f r o z e n a n d u n f r o z e n s o i l s , a n d e s p e c i a l l y t o c o m p u t e r m o d e l l i n g . T h e c o n c e p t o f n o r m a l f r o s t h e a v e ( p r i m a r y h e a v e ) h a s b e e n e x t e n d e d t o i n c l u d e t h a t o f s e c o n d a r y h e a v i n g . T h e o r y a n d e x p e r i m e n t s s u g g e s t t h a t a p p r e c i a b l e q u a n t i t i e s o f w a - t e r c a n m o v e t h r o u g h f r o z e n soils i n res - p o n s e t o t h e r m a l o r o t h e r g r a d i e n t s . T h e r o l e o f o v e r b u r d e n p r e s s u r e o n t h e m e c h - a n i s m o f i c e l e n s i n g r e m a i n s a c o n t r o v e r - s i a l q u e s t i o n . O f p a r t i c u l a r i n t e r e s t t o t h e g e o l o g i c c o n t r o l s o f g r o u n d i c e a n d l a b o r a t o r y s t u d i e s o n c h a n g e s i n t h e c r y - o g e n i c f a b r i c o f f r o z e n g r o u n d w h i c h r e - s u l t f r o m t e m p e r a t u r e f l u c t u a t i o n s a n d o t h e r f a c t o r s . F i e l d o b s e r v a t i o n s o n t h e l o w e r r e a c h e s o f t h e Y e n i s e i R i v e r h a v e c o n f i r m e d t h e r e s u l t s o f t h e l a b o r a t o r y i n v e s t i g a t i o n s ,

I c e Wedges

I m p o r t a n t a d v a n c e s h a v e b e e n m a d e o n t h e t h e o r e t i c a l a s p e c t s o f i c e - w e d g e c r a c k i n g . T h e t h e o r y a t t e m p t s t o p r e d i c t t h e t e m p e r a t u r e f i e l d r e q u i r e d to i n d u c e c r a c k i n g a n d t h e s p a c i n g , d e p t h , a n d w i d t h o f t h e r e s u l t i n g c r a c k s . D i f f e r e n c e s o f o p i n i o n h a v e b e e n e x p r e s s e d o n t h e s t r u c - t u r e a n d o r i g i n o f s o m e o f t h e t h i c k o l d P l e i s t o c e n e i c e w e d g e s o f N o r t h e r n Y a k u t i a .

i c e w e d g e c r a c k s o r i g i n a t e a t d e p t h , n o t a t t h e g r o u n d s u r f a c e . W e d g e - l i k e s t r u c t u r e s h a v e b e e n f o u n d i n t h e g e o - l o g i c r e c o r d , d a t i n g b a c k t o t h e P r e - c a m b r i a n i n C a n a d a , N o r w a y , S o u t h A f r i c a a n d e l s e w h e r e , b u t t h e f i e l d e v i d e n c e f o r a p e r m a f r o s t o r i g i n i s d e b a t a b l e .

P i n g o s a n d P a l s a s

A s m o r e d a t a a c c u m u l a t e , i t i s a p p a r e n t t h a t p i n g o i c e c o r e s c a n s h o w e v e r y g r a d a t i o n b e t w e e n p u r e i n j e c t i o n i c e a n d i c e r i c h m i n e r a l s o i l . Many p i n g o s h a v e b e e n f o u n d i n a b a n d o n e d c h a n n e l s . L a r g e p r e s s u r i z e d s u b - p i n g o w a t e r l e n s e s , a s much a s 2 . 2 m d e e p a n d w i t h d i a m e t e r s o f a t l e a s t 300 m , h a v e b e e n i d e n t i f i e d b y d e t a i l e d d r i l l i n g . T h e m a j o r f o c u s o f p a l s a r e s e a r c h c o n t i n - u e s to b e t h e l i f e c y c l e o f p a l s a s ; w h e t h e r p a l s a s a r e f a v o r e d b y i c e i n j e c - t i o n o r i c e s e g r e g a t i o n ; a n d w h e t h e r t h e f e a t u r e s a r e e s s e n t i a l l y d e g r a d a t i o n a l o r a g g r a d a t i o n a l i n o r i g i n .

M a s s i v e I c e

T h e r e i s a c o n t i n u i n g d i f f e r e n c e o f o p i n i o n o n t h e o r i g i n o f some of t h e m a s s i v e b o d i e s o f i c e f o u n d i n s o m e p e r - m a f r o s t a r e a s o f W e s t e r n S i b e r i a . A c c o r d - i n g t o o n e v i e w , s o m e w o r k e r s b e l i e v e t h e i c e t o b e b u r i e d g l a c i e r i c e . A c c o r d - i n g t o t h e o p p o s i n g v i e w , t h e i c e i s i n j e c t i o n , i n j e c t i o n - s e g r e g a t i o n , o r s e g r e g a t i o n i c e f o r m e d i n p l a c e . I n t h e W e s t e r n C a n a d i a n A r c t i c water q u a l i t y e v i d e n c e f a v o r s a n o n - g l a c i a l o r i g i n . I n some l o c a l a r e a s , i t m i g h t b e v e r y d i f f i - c u l t t o d i s t i n g u i s h b e t w e e n b u r i e d s u b - g l a c i e r r e g e l a t i o n i c e a n d d e b r i s r i c h s e g r e g a t i o n i c e .

G e o c h e m i s t r y o f G r o u n d I c e

T h e g e o c h e m i s t r y oE g r o u n d i c e , i n c l u d i n g t h e u s e of 6 t a b l e i s o t o p e s , a p p e a r s t o b e a p r o m i s i n g r e s e a r c h f i e l d

2

f o r t h e s t u d y o f i c e l e n s i n g , t h e g r o w t h o f p e r m a f r o s t , h y d r a u l i c c o n d u c t i v i t y o f f r o z e n s o i l s , c h a n g e s in t h e t h i c k n e s s o f t h e a c t i v e l a y e r , a n d i n p a l e o c r y o l o g i c r e c o n s t r u c t i o n s o f p a s t e n v i r q n m e n t s . O x y g e n i s o t o p e s h a v e b e e n u s e d t o p r o v i d e p a l e o c l i m a t i c i n f o r m a t i o n f r o m t h r e e a n t a r c t i c c o r e s a n d f r o m t h e M a c k e n z i e V a l l e y , C a n a d a .

T h e r m o k a r s t

O n e m a j o r a s p e c t o f r e c e n t r e s e a r c h h a s b e e n t h e m a p p i n g of t h e r m o k a r s t f e a t u r e s o v e r l a r g e a r e a s b y r e m o t e s e n s - i n g . D e t a i l e d i n v e s t i g a t i o n s h a v e b e e n c a r r i e d o u t i n t h e U.S.S.R. o n t h e a g e s o f t h e r m o k a r s t f e a t u r e s i n many perma- f r o s t r e g i o n s .

P e r m a f r o s t D i s t r i b u t i o n

T h e w o r l d w i d e d i s t r i b u t i o n o f a l - p i n e p e r m a f r o s t h a s b e e n e x t e n d e d i n t e m p e r a t e a n d t r o p i c a l r e g i o n s , s u c h a s i n t h e P a m i r , T i e n S h a n , A n d e s , a n d H a w a i i . A g r e a t d e a l o f p r o g r e s s h a s b e e n m a d e i n t h e m a p p i n g o f s u b m a r i n e p e r m a f r o s t i n t h e a r c t i c w a t e r s o f E u r a s i a a n d N o r t h A m e r i c a . T h e o r e t i c a l a s p e c t s h a v e b e e n d i s c u s s e d i n s o m e d e t a i l .

P a l e o c r y o l o g i c a l S t u d i e s

P a l e o c r y o l o g i c a l s t u d i e s h a v e b e e n d e v e l o p e d t o t h e g r e a t e s t e x t e n t i n t h e U . S . S . R . T h e r e h a v e b e e n n u m e r o u s d i v e r s e s t u d i e s s u c h a s o n t h e r e l a t i o n b e t w e e n t h e c r y o g e n i c s t r u c t u r e a n d t h e t h e r m a l r e g i m e o f p e r m a f r o s t , t h e h o r i z o n s w h i c h m i g h t b e f o r m e d b y e p i g e n e t i c f r e e z - i n g i n f i n e g r a i n e d s o i l s , a n d t h e r e c o n - s t r u c t i o n o f p a l e o c l i m a t e f r o m p r e s e n t d a y g e o t h e r m a l d a t a . C r y o g e n i c W e a t h e r i n g

The i n t e r a c t i o n o f w a t e r w i t h d i f f e r e n t s t r u c t u r a l g r o u p s o f r o c k - f o r m - i n g m i n e r a l s h a s b e e n i n v e s t i g a t e d a n d a t h e o r e t i c a l m o d e l o f m i n e r a l s t a b i l i t y w i t h r e s p e c t t o r o c k w e a t h e r i n g p r e s e n t e d . The r e s u l t s s h o w t h a t t h e u l t i m a t e g r a i n s i z e d i s t r i b u t i o n s f o r t h e b a s i c r o c k - f o r m i n g m i n e r a l s i n a c o l d a r e a w i t h f r e e z e - t h a w c y c l e s a r e o p p o s i t e t o a warm a r e a w i t h o u t t h e c y c l e s .

C r y o l i t h o g e n e s i s

A l t h o u g h t h e r e i s n o u n i f o r m i t y i n t h e u s e o f t h e t e rm, many i , n v c s t i g a t o r s h a v e b e e n c o n c e r n e d w i t h t h e t o p i c . A c r y o l i t h o l o g i c a l map o f t h e U . S . S . R . h a s b e e n c o m p i l e d on a s c a l e o f 1 : 4 , 0 0 0 , 0 0 0 . The map c l e a r l y s h o w s t h e r e g i o n a l o c c u r - r e n c e o f p e r m a f r o s t a n d t h e t w o m a i n t y p e s , e p i g e n e t i c a n d s y n g e n e t i c . T h e map p r o v i d e s a w e a l t h o f i n f o r m a t i o n o n c r y o g e n i c

t e x t u r e s , t h e e s t i m a t e d a r ea o f f r o z e n g r o u n d , a n d t h e r e l a t i o n b e t w e e n t h e d i s t r i b u t i o n o f f r o z e n g r o u n d a n d i t s g e n e s i s i n t h e U.S . S . R .

I N T R O D U C T I O N

T h e g e o l o g i c a l c o n t r o l s o f t h e o r i g i n , c h a r a c t e r i s t i c s , a n d d i s t r i b u - t i o n o f g r o u n d i c e i n t h e p e r m a f r o s t a r e a s o f t h e w o r l d a r e n u m e r o u s a n d t h e r e c e n t p u b l i s h e d l i t e r a t u r e i s v e r y e x t e n s i v e . A t t h e F i r s t I n t e r n a t i o n a l C o n f e r e n c e o n P e r m a f r o s t ( L a f a y e t t e , I n d i a n a , U . S . A . , 1 9 6 3 ) t h e r e w a s a p a n e l d i s c u s s i o n o n M a s s i v e G r o u n d I c e . I n a d d i t i o n , p a p e r s r e l a t i n g t o g r o u n d i c e were p r e s e n t e d i n s e s s i o n s o n s o i l s , v e g e t a t i o n , g e o m o r p h o l o g y , a n d p h a s e e q u i l i b r i a a n d t r a n s i t i o n s , A r t h e S e c o n d I n t e r n a t i o n a l C o n f e r e n c e on P e r m a f r o s t ( Y a k u t s k U . S . S . R . , 1 9 7 3 ) S o v i e t a n d N o r t h A m e r i c a n s c i e n t i s t s p r e p a r e d t w o r e v i e w p a p e r s o n t h e g e n e s i s , c o m p o s i t i o n , a n d s t r u c t u r e o f f r o z e n g r o u n d a n d g r o u n d i c e . T h e 1 9 7 3 S o v i e t a n d N o r t h A m e r i c a n P r o c e e d i n g s a l s o c o n t a i n n u m e r o u s p a p e r s o n v a r i o u s a s p e c t s o f g r o u n d i c e w i t h c o n t r i b u t i o n s f r o m many c o u n t r i e s o f t h e w o r l d . T h i s r e v i e w p a p e r h a s b e e n a c o l l a b o r a t i v e e f f o r t w i t h t h e two S o v i e t a u t h o r s a s s u m i n g p r i m e r e s p o n s i b i l i t y f o r t h e l i t e r a t u r e o f t h e S o v i e t U n i o n a n d t h e C a n a d i a n a u t h o r p r i m e r e s p o n s i b i l i t y f o r t h e n o n - S o v i e t m a t e r i a l . I n v i e w o f t h e f a c t t h a t t h e r e a r e f r e q u e n t l y n o p r e c i s e E n g l i s h - R u s s i a n e q u i v a l e n t s f o r m a n y p e r m a f r o s t terms, s o m e o f t h e E n g l i s h w o r d s u s e d i n t h i s r e v i e w d o n o t c o n v e y t h e p r e c i s e m e a n i n g o f t h e i r R u s s i a n c o u n t e r p a r t s ( B r o w n a n d K u p s c h 1 9 7 4 ; F y o d o r o v 1 9 7 4 ; P o p p e a n d B r o w n 1 9 7 6 ; v a n E v e r d i n g e n 1 9 7 6 ) . F o r t h i s r e a s o n , b r a c k e t e d t e r m s w i l l b e u s e d f r e q u e n t l y t o i n d i c a t e s u b s t i t u t e w o r d s w h i c h m i g h t h e l p t o c l a r i f y t h e m e a n i n g . I n a b r i e f r e v i e w o f t h e 1 9 7 3 - 1 9 7 8 w o r l d l i t e r a t u r e , w h i c h c o n s i d e r a b l y e x c e e d s t h r e e h u n d r e d p u b l i c a t i o n s , t h e r e v i e w a u t h o r s a r e v e r y much aware o f t h e f a c t t h a t i t i s o b v i o u s l y i m p o s s i b l e t o c i t e a l l p a p e r s ; t o g i v e e q u a l e m p h a s i s t o a l l t o p i c s ; a n d t o r e v i e w a d e q u a t e l y e v e n t h o s e t o p i c s w h i c h a r e d i s c u s s e d . H o w e v e r , a n e f f o r t h a s b e e n m a d e t o d i s c u s s s o m e o f t h e m o r e i m p o r t a n t r e c e n t r e s e a r c h a n d t o m e n t i o n a n u m b e r o f t h e m o r e s p e c i a l i z e d r e v i e w p a p e r s a n d c o n - f e r e n c e p r o c e e d i n g s w h e r e a d d i t i o n a l m a t e r i a l o n g r o u n d i c e c a n b e f o u n d .

G E N E R A L R E V I E W S

Two m o n o g r a p h s , t h e f i r s t b y V r y u r i n a ( 1 9 7 4 ) o n " T h e c r y o g e n i c s t r u c - t u r e o f t h e s e a s o n a l l y t h a w i n g l a y e r " a n d t h e s e c o n d b y V t y u r i n ( 1 9 7 5 ) o n

3

" U n d e r g r o u n d i c e in r h e U . S . S . R . " p r o v i d e i n c o m b i n a t i o n a n e x c e l l e n t o v e r a l l r e v i e w o f u n d e r g r o u n d i c e . V t y u r i n a ( 1 9 7 4 ) d i s c u s s e s t h e c r y o g e n i c f a b r i c ( s t r u c t u r e ) o f t h e a c t i v e l a y e r . D i a g r a m s , c r o s s s e c t i o n s , a n d p h o t o g r a p h s i l l u s t r a t e c r y o g e n i c f a b r i c s ( J u m i k i s 1 9 7 7 ) p r o d u c e d i n d i f f e r e n t s o i l t y p e s b y b o t h d o w n w a r d f r e e z i n g o f t h e a c t i v e l a y e r f r o m t h e g r o u n d s u r f a c e a n d u p w a r d f r e e z i n g f r o m t h e f r o s t t a b l e . V t y u r i n ( 1 9 7 5 ) h a s s u m m a r i z e d d a t a on t h e d i f f e r e n t r e g i o n s o f t h e S o v i e t U n i o n a n d h a s p r o p o s e d a g e n e t i c c l a s s i f i - c a t i o n o f u n d e r g r o u n d i c e i n c l u d i n g p r i m a r y g r o u n d i c e ( i c e c e m e n t , s e g r e g a t e d i c e , i c e l e n s e s , i c e b e d s ) a n d s e c o n d a r y g r o u n d i c e ( i c e w e d g e s , v e i n i c e , cave i c e ) , B u r i e d i c e ( r i v e r i c e , g l a c i e r i c e ) i s a l s o c o n - s i d e r e d . V t y u r i n h a s a l s o d e t e r m i n e d t h e r e g i o n a l d i s t r i b u t i o n o f g r o u n d i c e i n t h e U.S.S.R, a n d h a s e s t i m a t e d i t s t o t a l v o l u m e . N e k r a s o v ( 1 9 7 6 ) h a s w r i t t e n a r e g i o n a l r e v i e w o n t h e m o r p h o l o g y , r h i c k - n e s s , t h e r m a l r e g i m e , a n d r e l a t e d p e r m a - f r o s t f e a t u r e s o f a l a r g e , m a i n l y moun- t a i n o u s r e g i o n i n t h e n o r t h e a s t a n d s o u t h o f S i b e r i a , c o m p l e t e w i t h a map on a s c a l e 1 / 2 , 5 0 0 , 0 0 0 . F o t i e v e t a l . ( 1 9 7 4 ) h a v e d e s c r i b e d t h e g e n e r a l g e o c r y o l o g i c a l c o n d i t i o n s o f a v a s t , p o o r l y s t u d i e d r e g i o n o f c e n t r a l S i b e r i a . T h e a u t h o r s a l s o s h o w t h a t w a t e r , a t a n e g a t i v e t e m p e r - a t u r e , i s w i d e s p r e a d a t d e p t h b e n e a t h i c e - b o n d e d p e r m a f r o s t . B a d u a n d T r o f i . m o v ( 1 9 7 4 ) h a v e c a r r i e d o u t c r y o g e n i c s t u d i e s i n t h e Yamal P e n i n s u l a . T h e U . S . Army C o l d R e g i o n s R e s e a r c h a n d E n g i n e e r i n g L a b o r a t o r y , H a n o v e r , N.H., U . S . A , h a s p u b - l i s h e d many t e c h n i c a l p a p e r s r e l a t i n g t o g r o u n d i c e . J a h n ' s b o o k on " P r o b l e m s o f t h e P e r i g l a c i a l Z o n e " , o r i g i n a l l y p u b l i s h e d i n P o l i s h , h a s b e e n t r a n s l a t e d i n t o E n g l i s h ( J a h n 1 9 7 5 ) . T h e b o o k is w o r l d w i d e i n i t s c o v e r a g e o f p e r i g l a c i a l t o p i c s a n d t h e r e f e r e n c e s a r e m u l t i l i n g u a l . PPw6 ( 1 9 7 5 ) h a s w r i - t t e n a m o n o g r a p h o n t h e " Q u a t e r n a r y G e o l o g y o f A l a s k a " , i n w h i c h g r o u n d i c e i s i n c l u d e d , b u t it i s n o t t h e m a i n t o p i c . F o r C a n a d a , a w i d e l y s c a t t e r e d l i t e r a t u r e o n g r o u n d i c e c a n b e f o u n d i n t h e n u m e r o u s r e p o r t s p r e p a r e d f o r t h e E n v i r o n m e n t a l - S o c i a l C o m m i t t e e , N o r t h e r n P i p e l i n e s ( O t t a w a : T a s k F o r c e o n N o r t h e r n O i l D e v e l o p m e n t ) a n d i n o t h e r r e p o r t s ( e g . H e g i n b o t t o m e t a l . 1 9 7 8 ) d e a l i n g w i t h a p r o p o s e d , b u t now d e f u n c t , M a c k e n z i e V a l l e y P i p e l i n e . T h e m o s t c o m p r e h e n s i v e E n g l i s h l a n g u a g e b o o k w h i c h i n c l u d e s g r o u n d i c e is W a s h b u r n ' s ( i n p r e s s ) " G e o c r y o l o g y : A S u r v e y o f P e r i g l a c i a l P r o c e s s e s a n d E n v i r o n m e n t s " .

FROST HEAVE AND I C E L E N S I N G

T h e o r e t i c a l C o n s i d e r a t i o n s

Ice s e g r e g a t i o n a n d f r o s t h e a v i n g h a v e b e e n t h e t o p i c o f s e v e r a l r e c e n t

i n t e r n a t i o n a l c o n f e r e n c e s ( A g u i r r e - P u e n t e 1 9 7 8 ; F r o s t A c t i o n i n S o i l s , P r o c e e d i n g s o f a n I n t e r n a t i o n a l S y m p o s i u m , U n i v e r s i t y o f L u l e z , S w e d e n , 1 9 7 7 , V o l s . 1 a n d 2 : S o i l - W a t e r P r o b l e m s i n C o l d R e g i o n s , P r o c e e d i n g s o f t h e F i r s t a n d S e c o n d C o n f e r e n c e s , C a l g a r y , C a n a d a , 1 9 7 5 a n d E d m o n t o n , C a n a d a , 1 9 7 6 ; I n t e r n a t i o n a l Symposium on G r o u n d F r e e z i n g , R u h r U n i v e r - s i t y , B o c h u m , G e r m a n y , 1 9 7 8 ) , C o n s i d e r - a b l e a t t e n t i o n h a s b e e n p a i d t o t h e t h e o r e t i , c a l a s p e c t s o f i c e l e n s i n g s i n c e 1 9 7 3 . T h e c a p i l l a r y m o d e l f o r non- c o l l o i d a l s o i l s h a s b e e n c r i t i c i z e d b y T a k a g i ( 1 9 7 7 ) o n t h e g r o u n d s t h a t t h e m o d e l a p p l i e s t o s t a t i c c o n d i t i o n s w h e r e a s t h e f r e e z i n g o f p o r e w a t e r i s a k i n e m a t i c e f f e c t w h i c h r e q u i r e s a d i f f e r - e n t t h e r m o d y n a m i c a p p r o a c h , Mil ler a n d c o l l e a g u e s ( M i l l e r 1 9 7 8 ) h a v e e x t e n d e d t h e c a p i l l a r y m o d e l t o i n c l u d e t h e c o n c e p t o f s e c o n d a r y h e a v i n g . T h i s i n v o l v e s a s e r i e s - p a r a l l e l t r a n s p o r t o f m o v i n g p o r e i c e a n d u n f r o z e n warer w h e r e t h e r i g i d p o r e i c e p h a s e a n d t h e i n c o m p r e s s i b l e m i n e r a l p a r t i c l e s i n t e r - a c t v i a a n i n t e r v e n i n g w a t e r f i l m w i t h p r o p e r t i e s w h i c h t e n d t o d r i v e t h e i c e p h a s e i n t h e d i r e c t i o n of d e c r e a s i n g t e m p e r a t u r e a n d t h e g r a n u l a r s k e l e t o n i n t h e o p p o s i t e d i r e c t i o n . A l t h o u g h a n i c e - w a t e r f r i n g e i s c o n s i d e r e d t o b e c h a r a c t e r i s t i c o f i c e l e n s g r o w t h i n c l a y s o i l s , t h e r e i s d i s a g r e e m e n t on t h e p r e s e n c e o f a n a c t i v e i c e - w a t e r f r i n g e b e l o w a g r o w i n g i c e l e n s in n o n - c o l l o i d a l s o i l s ( P e n n e r 1 9 7 7 ) .

T h e p r o b l e m o f s i m u l t a n e o u s h e a t a n d m a s s t r a n s p o r t i n f r o z e n a n d u n f r o z e n s o i l s h a s r e c e i v e d much a t t e n t i o n , p a r t i c u l a r l y i n t h e f i e l d o f c o m p u t e r m o d e l l i n g ( e g . Guymon a n d L u t h i n 1 9 7 4 ; O u r c a l t 1 9 7 7 ; S h e p p a r d e t a l . 1 9 7 8 ) . S t u d i e s h a v e s h o w n t h a t a p p r e c i a b l e water can move i n f r o z e n s o i l s i n r e s p o n s e t o i m p o s e d t h e r m a l g r a d i e n t s ( A n d e r s o n 1 9 7 7 ; Wil l iams 1 9 7 6 ) . In r h i s r e s p e c t , Wil l iams ( 1 9 7 7 ) c o n c l u d e s t h a t u n d e r c e r t a i n c o n d i t i o n s t h e s u c t i o n a t t h e f r o s t l i n e t h a t d e t e r m i n e s t h e m i g r a t i o n o f w a t e r t h r o u g h t h e u n f r o z e n s o i l may b e c o n s e q u e n t u p o n s u c t i o n s h a v i n g t h e i r o r i g i n w e l l w i t h i n t h e f r o z e n z o n e . Water f i l l e d v e i n s c a n o c c u r i n p o l y c r y s t a l l i n e i c e (Raymond a n d H a r r i s o n 1 9 7 5 ) a n d i n i c e l e n s e s . O s t e r k a m p ( 1 9 7 5 ) has o b s e r v e d l i q u i d f i l l e d t h r e e - g r a i n b o u n d a r i e s d e v e l o p e d i n i c e l e n s e s a t a n e a r l y s t a g e i n t h e m e l t i n g p r o c e s s a n d h e h a s s t r e s s e d t h e i r a b i l i t y t o a c t a s c h a n n e l s f o r w a t e r f l o w d u r i n g f r e e z i n g a n d m e l t i n g . Wil l iams ( 1 9 7 7 ) h a s l i k e w i s e c o n c l u d e d t h a t t h e e x i s t e n c e o f i c e l e n s e s 2 t o 3 cm t h i c k may n o t p r o h i b i t w a t e r m o v e m e n t i n f r o z e n s o i l s ( P e n n e r 1 9 7 7 ) . N u c l e a r m a g n e t i c r e s o n a n c e (NMR) t e c h n i q u e s h a v e b e e n u s e d t o s t u d y u n f r o z e n w a t e r i n

4

f r o z e n s o i l s ( K v l i v i d z e e t a l . 1 9 7 8 ; T i c e e t a l . 1 9 7 8 . A c c o r d i n g t o T i c e e t a l . 1 9 7 8 ) r h e r e s u l t s s h o w , c o n t r a r y t o p r e v i o u s c o n c l u s i o n s , t h a t t h e u n f r o z e n w a t e r c o n t e n t d e t e r m i n e d b y t h e t e c h n i q u e s o f p u l s e d NMR d e p e n d u p o n t h e i c e c o n t e n t .

The r o l e o f o v e r b u r d e n p r e s s u r e o n t h e m e c h a n i s m o f i c e l e n s i n g r e m a i n s a c o n r r o v e r s i a l q u e s t i o n ( L o c h a n d Kay 1 9 7 8 ) . A c c o r d i n g t o o n e s c h o o l o f t h o u g h t , f o r e a c h s o i l t h e r e i s a s h u t - o f f p r e s s u r e a t w h i c h t h e e f f e c t i v e s t r e s s a t t h e f r o s t f r o n t w i l l c a u s e n e i t h e r f l o w o f w a t e r i n t o o r a w a y f r o m t h e f r e e z i n g f r o n t ( M c R o b e r t s a n d N i x o n 1 9 7 5 ) . When t h e s h u t - o f f p r e s s u r e i s e x c e e d e d w a t e r i s t h e n e x p e l l e d i n a d v a n c e o f t h e f r e e z i n g f r o n t ( H i l l a n d M o r g e n - s t e r n 1 9 7 7 ) . T a k a s h i e t a l . ( 1 9 7 8 ) h a v e f o u n d t h a t h e a v i n g d e c r e a s e d r a p i d l y w i t h a n i n c r e a s e i n e f f e c t i v e s t r e s s a n d t h e y h a v e p r o p o s e d a m o d e l f o r s u c t i o n / d i s c h a r g e a t t h e f r e e z i n g f r o n t . On t h e o t h e r h a n d , t h e r e i s e x p e r i m e n t a l e v i d e n c e t h a t t h e o b s e r v e d w a t e r e x p u l - s i o n i n s o m e e x p e r i m e n t s may b e o n l y t e m p o r a r y . P e n n e r a n d U e d a ( 1 9 7 8 ) h a v e f o u n d t h a t t h e r a t i o o f i n s i t u t o m i g r a - t o r y w a t e r w h i c h i s f r o z e n c a n c h a n g e c o n r i n u o u s l y d u r i n g a t e s t a n d h a s n o i n f l u e n c e o n t h e h e a v e r a t e . In t h e i r e x p e r i m e n t s , t h e s i g n i f i c a n t f a c t o r i n d e t e r m i n i n g t h e h e a v e r a t e was t h e v a l u e o f t h e c o l d - s i d e t e m p e r a t u r e w h i c h P e n n e r a n d U e d a c o n s i d e r d e t e r m i n e s t h e s u c t i o n p o t e n t i a l a t t h e g r o w i n g i c e l e n s . T h e r e v e r s a l f r o m i n i t i a l w a t e r e x p u l s i o n t o s u b s e q u e n t w a t e r i n t a k e i s n o t f u l l y u n d e r s t o o d (Hi11 a n d M o r g e n s t e r n 1 9 7 7 ) . L o c h a n d M i l l e r ( 1 9 7 5 ) a t t r i b u t e t h e e x p u l s i o n t o n u c l e a t i o n r e f l e c t i n g v o l u m e c h a n g e s o f f r e e z i n g p o r e w a t e r to f o r m p o r e i c e a n d i n t a k e to t h e s e g r e g a t i o n o f i c e l e n s e s .

Me lamed and Medvedev (1974) , de - v e l o p i n g G o l d s h t e i n ' s c o n c e p t ( G o l d s h t e i n 1 9 5 2 ) o f t h e e x i s t e n c e o f a n o p t i m u m t e m p e r a t u r e o f f r e e z i n g , a t w h i c h t h e r e i s a maximum a m o u n t o f i c e s e g r e g a t i o n w i t h o t h e r c o n d i t i o n s b e i n g e q u a l , h a v e s p e c i f i e d t h e o p t i m u m c o n d i t i o n s o f g r o w t h o f s e g r e g a t e d i c e i n f i n e - g r a i n e d s o i l s ( f i n e - d i s p e r s e d r o c k s ) a n d h a v e g i v e n a m a t h e m a t i c a l f o r m u l a t i o n f o r c o m p u t e r s o l v i n g o f t h e p r o b l e m o f i c e l e n s i n g .

A g r o u p o f w o r k e r s u n d e r r h e l e a d e r s h i p o f E r s h o v ( E r s h o v e t a l . 1 9 7 8 a , 1 9 7 8 b ) h a v e c a r r i e d o u t e x t e n s i v e l a b o r a - t o r y i n v e s t i g a t i o n s i n t h e f o r m a t i o n o f p o r e a n d l e n s i c e b y i n v e s t i g a t i n g h e a t a n d mass t r a n s f e r i n t h e f r e e z i n g a n d t h a w i n g o f d i f f e r e n t s o i l t y p e s u n d e r a w i d e r a n g e o f f r e e z i n g r a t e s . E r s h o v ( 1 9 7 7 ) h a s d i s t i n g u i s h e d b e t w e e n t h e

n e c e s s a r y a n d s u f f i c i e n t c o n d i t i o n s f o r t h e f o r m a t i o n o f c r y o g e n i c f a b r i c s ( t e x t u r e s ) i n f r e e z i n g s o i l s . The n e c e s s a r y c o n d i t i o n s a r e t h e t h e r m o - p h y s i c a l f a c t o r s o f h e a t a n d mass e x c h a n g e . But p r o c e e d i n g Erom t h e f a c t o r s o f h e a t a n d mass e x c h a n g e , i t i s i m p o s s i b l e s o f a r , a c c o r d i n g t o E r s h o v , t o e x p l a i n f u l l y t h e n a t u r e o f i c e s e g r e g a t i o n . The s u f f i c i e n t c o n d i t i o n f o r i c e s e g r e g a t i o n i s a p h y s i c a l - m e c h a n i c a l r a t i o b e t w e e n t h e t e n s i l e s t r e n g t h o f t h e s o i l a n d t h e e x p a n s i o n f o r c e s a t t e n d a n t u p o n s o i l f r e e z i n g .

C r y o g e n i c F a b r i c s ( T e x t u r e s )

R e c e n t s t u d i e s h a v e s h o w n t h a t t h e c r y o g e n i c f a b r i c o f f r o z e n g r o u n d c a n c h a n g e i n r e s p o n s e t o p r e s s u r e , t e m p e r a t u r e , a n d o t h e r f a c t o r s . Ershov ( 1 9 7 7 ) was t h e f i r s t t o d e m o n s t r a t e e x p e r i m e n t a l l y t h e c h a n g e o f o n e c r y o g e n i c f a b r i c i n t o a n o t h e r , i n p a r t i c u l a r , t h e c h a n g e o f a massive t e x t u r e ( c e m e n t i c e ) i n t o a n i c e l e n s e d ( s c h l i e r e n ) t y p e as a s o i l warms a n d t h a w s . E r s h o v ' s l a b o r a t o r y e x p e r i m e n t s h a v e b e e n c o n f i r m e d b y P a r m u z i n a ( 1 9 7 7 ) f r o m f i e l d o b s e r v a t i o n s i n t h e b a s i n o f t h e l o w e r r e a c h e s o f t h e Y e n i s e i R i v e r , U . S . S . R . A c h a n g e f r o m a m a s s i v e t e x t u r e o f p o r e i c e t o a l e n s e d t e x t u r e was n o t e d i n t h a w i n g o f t h e a c t i v e l a y e r .

I m p o r t a n t e x p e r i e m n t a l r e s e a r c h i n t o t h e d y n a m i c s o f i c e l e n s i n g h a s a l s o b e e n c a r r i e d o u t b y Z h e s t k o v a ( 1 9 7 8 ) a n d Z h e s t k o v a a n d G u z h o v ( 1 9 7 6 ) . I n o n e f r e e z i n g e x p e r i m e n t l a s t i n g 2 2 d a y s , a s l o w b u t p e r s i s t e n t c h a n g e i n i c e l e n s e s a n d s o i l f a b r i c was o b s e r v e d i n t h e f r o z e n z o n e . When a n i c e l e n s ( s c h l i e r e n ) f o r m e d a n d g r e w , t h e m i n e r a l a g g r e g a t e s b r o k e a w a y f r o m t h e s o i l b e n e a t h t h e l e n s a n d m o v e d s l o w l y o r were f o r c e d o u t b y t h e i c e . T h e m o v e m e n t o f t h e m i n e r a l a g g r e g a t e s in t h e e x p e r i m e n t a v e r a g e d a f r a c t i o n o f a m i l l i m e t r e a d a y . T h e p r o b a b i l i t y o f a n i c e - s a t u r a t e d s o i l l a y e r , g i v e n a n y t y p e o f i c e f a b r i c , c h a n g i n g i n t o a n e x t e n s i v e i c e l e n s i n c r e a s e s w i t h t h e d e g r e e o f i c e s a t u r - a t i o n o f t h e l a y e r a s i t f o r m s . I c e l e n s ( s c h l i e r e n ) g r o w t h i s f a v o u r e d w h e n t h e t e m p e r a t u r e f l u c t u a t e s in r e s p o n s e t o v a r i a t i o n s i n t h e s u r f a c e t e m p e r a t u r e . T h e d e p e n d e n c e o f t h e s t r u c t u r a l c h a r a c - t e r i s t i c s o f a n i c e l e n s o n t h e mine ra l c o m p o s i t i o n o f t h e s u b j a c e n t m a t e r i a l h a s b e e n c o r r o b o r a t e d e x p e r i m e n t a l l y b y G o l u b e v a n d K a b a n o v a ( 1 9 7 6 ) . M a k s i m o v a ( 1 9 7 7 ) h a s d e r i v e d a c l a s s i f i c a t i o n s c h e m e f o r c r y o g e n i c t e x t u r e s i n f i n e g r a i n e d soils.

Comment

T h e t h e o r e t i c a l a n d l a b o r a t o r y

5

s t u d i e s o n f r o s t h e a v e , i c e l e n s i n g , a n d c h a n g e s i n c r y o g e n i c f a b r i c h a v e m a d e i m p o r t a n t c o n t r i b u t i o n s t o o u r u n d e r s t a n d - i n g o f t h e g e n e s i s o f p r i m a r y g r o u n d i c e a n d y e t , a t t h e same t ime , i m p o r t a n t q u e s t i o n s h a v e b e e n r a i s e d . C l e a r l y t h e r e a r e s c a l i n g p r o b l e m s i n t r a n s f e r r i n g l a b o r a t o r y s t u d i e s t o f i e l d c o n d i t i o n s w h e r e f r e e z i n g r a t e s , t ime p e r i o d s , p r e s s u r e s a n d s o f o r r h c a n v a r y b y s e v e r a l o r d e r s o f m a g n i t u d e . F o r e x a m p l e , a v e r y low h y d r a u l i c c o n d u c t i v i t y o f a f r o z e n s o i l o r a s l o w t e m p e r a t u r e i n d u c e d c h a n g e in c r y o g e n i c f a b r i c may b e o f l i t t l e c o n - s e q u e n c e i n a n e x p e r i m e n t , b u t o f a p p r e c - i a b l e c o n s e q u e n c e g i v e n a g e o l o g i c t ime s c a l e .

MASSIVE ( B E D D E D ) T C E

Massive b o d i e s o f i c e a r e c h a r a c - t e r i s t i c o f s o m e p e r m a f r o s t a r e a s of W e s t e r n S i b e r i a ( S o l o m a t i n 1 9 7 7 ) a n d t h e W e s t e r n C a n a d i a n A r c t i c ( R a m p t o n 1 9 7 4 ; R a m p t o n a n d W a l c o t t 1 9 7 4 ) . I n t h e U.S.S.R., u n t i l r e c e n t l y m o s t oE t h e b e d d e d i c e w a s r e g a r d e d a s i n j e c t i o n , i n j e c t i o n - s e g r e g a t i o n , o r s e g r e g a t i o n i c e , a l t h o u g h i n s o m e o f t h e e a r l i e r p u b l i c a t i o n s , t h e i c e w a s b e l i e v e d t o b e b u r i e d s u r f a c e i c e , p a r t i - c u l a r l y g l a c i e r i c e ( S a k s a n d A n t o n o v 1 9 4 5 ) . R e c e n t l y , K a p l y a n s k a y a a n d T a r n o g r a d s k y ( 1 9 7 6 ) a n d s o m e o t h e r w o r k e r s h a v e r e v i v e d t h e s u g g e s t i o n o f a g l a c i e r o r i g i n . S o l o m a t i n ( 1 9 7 7 ) h a s p r e s e n t e d d a t a t o s u p p o r t t h e i n i t i a l l y s u p e r f i c i a l o r i g i n o f t h e b e d d e d i c e . Tn t h e W e s t e r n C a n a d i a n A r c t i c t h e r e c o u l d w e l l b e s o m e b u r i e d g l a c i e r i c e . H o w e v e r , m o s t o f t h e m a s s i v e ( b e d d e d ) i c e i s p r o b a b l y i n j e c - t i o n , i n j e c t i o n - s e g r e g a t e d , o r s e g r e g a t e d i c e , b e c a u s e o f t h e s t r a t i g r a p h i c a s s o c - i a t i o n w i t h f o s s i l i f e r o u s s e d i m e n t s , t h e i c e p e t r o f a b r i c s , a n d t h e i c e ( w a t e r ) q u a l i t y c o m p o s i t i o n . I n s o m e cases , i t may b e v e r y d i f f i c u l t t o d i s t i n g u i s h b e t w e e n b u r i e d s u b g l a c i e r r e g e l a t i o n i c e ( C l a p p e r t o n 1 9 7 5 ) a n d d e b r i s r i c h s e g r e - g a t i o n i c e , b e c a u s e o f s i m i l a r i t i e s i n a p p e a r a n c e .

I C E WEDGES

I c e w e d g e s a n d w e d g e s t r u c t u r e s h a v e l o n g b e e n s t u d i e d i n t e n s i v e l y i n a r e a s o f c o n t e m p o r a r y p e r m a f r o s t , i n p e r i - g l a c i a l a r e a s , a n d m o r e r e c e n t l y i n t h e g e o l o g i c r e c o r d . R o m a n o v s k i i ( 1 9 7 3 , 1 9 7 7 , 1 9 7 8 ) h a s w r i t t e n i n c o n s i d e r a b l e d e t a i l o n i c e w e d g e s a n d r e l a t e d f e a t u r e s . H e s u b d i v i d e s t h e s t r u c t u r e s i n t o t w o g r o u p s . The c l a s s i f i c a t i o n i s a p p l i c a b l e t o b o t h e p i g e n e t i c a n d s y n g e n e t i c f o r m s . T h e p r i m a r y s t r u c t u r e s a r e t h o s e f o r m e d b y r e p e a t e d f r o s t c r a c k i n g , w i t h i n f i l l i n g o f t h e r e s u l t i n g c r a c k s w i t h i c e o r e a r t h m a t e r i a l s . T h e s e c o n d a r y s t r u c t u r e s a r e

f o r m e d a s a r e s u l t o f t h a w i n g o f t h e p r i m a r y s t r u c t u r e s . B o t h p r i m a r y a n d s e c o n d a r y s t r u c t u r e s h a v e b e e n d i v i d e d , b y R o m a n o v s k i i , i n t o s u b t y p e s d e p e n d i n g u p o n c r i t e r i a s u c h as p o s i t i o n w i t h i n t h e s e a s o n a l l y t h a w e d ( f r o z e n ) l a y e r and t h e n a t u r e o f t h e i n f i l l i n g m a t e r i a l .

T h e o r e t i c a l

I m p o r t a n t a d v a n c e s o n t h e t h e o r y o f i c e - w e d g e c r a c k i n g h a v e b e e n made b y G r e c h i s h c h e v ( 1 9 7 5 , 1 9 7 6 , 1 9 7 8 ) . T h e t h e o r e t i c a l s o l u t i o n s a r e d i f f i c u l t t o a p p l y t o f i e l d c o n d i t i o n s b e c a u s e o f u n c e r t a i n t i e s i n o u r k n o w l e d g e o f v e r t i c a l a n d h o r i z o n t a l t e m p e r a t u r e g r a d i e n t s ; i c e c o n t e n t a n d s o i l t y p e ; s e a s o n a l c h a n g e s i n t h e r h e o l o g i c p r o - p e r t i e s o f t h e a c t i v e l a y e r , w e d g e i c e , a n d p e r m a f r o s t ; a n d i n h o m o g e n i e t i e s i n t h e m i c r o r e l i e f . N e v e r t h e l e s s , G r e c h i - s h a h e v h a s b e e n a b l e t o i n t e g r a t e s o m e o f t h e s e f a c t o r s i n t o a t h e o r y w h i c h a t t e m p t s t o p r e d i c t t h e t e m p e r a t u r e f i e l d r e q u i r e d t o i n d u c e c r a c k i n g , a n d t h e s p a c i n g , d e p t h , a n d w i d t h o f t h e r e s u l t i n g c r a c k s . G a s a n o v ( 1 9 7 6 , 1 9 7 8 ) h a s a n a l y s e d t h e b a s i c f a c t o r s ' t h a t c o n t r o l t h e u l t i m a t e s i z e o f i c e w e d g e s ( r e c u r r e n t - v e i n i c e ) a n d h a s d i s t i n g u i s h e d f o u r p o s s i b l e c a t e - g o r i e s a n d f o u r v a r i a n t s o f i c e - w e d g e ( i c e v e i n ) g r o w t h d e p e n d i n g u p o n : a ) t h e d e p t h o f f r o s t - i n d u c e d c r a c k i n g ; b) t h e d e p t h o f s e a s o n a l t h a w i n g ; c ) t h e r a t e o f s e d i m e n t a t i o n ; a n d d ) t h e h o r i z o n t a l g r o w t h r a t e o f t h e a n n u a l ( e l e m e n t a r y i c e v e i n l e t .

P l e i s t o c e n e I c e - W e d ~ e G r o w t h

T h e m o s t c o m p r e h e n s i v e d a t a o n t h e s t r u c t u r e of t h e t h i c k o l d P l e i s t o c e n e i c e w e d g e s ( p o l y g o n a l w e d g e i c e ) a r e p r e s e n t e d b y S o l o m a t i n ( 1 9 7 4 ) . S o l o m a t i n c o n s i d e r s t h a t t h e s t r u c t u r e o f t h e o l d i c e w e d g e s d i f f e r s e s s e n t i a l l y f r o m t h a t o f t h e y o u n g e p i g e n e t i c i c e w e d g e s i n w h i c h t h e s t r u c t u r e o f t h e v e i n l e t s ( e l e m e n t a r y v e i n l e t s ) a r e d i s t i n c t a n d r e c o g n i z a b l e . S o l o m a t i n h a s c o m e t o t h e c o n c l u s i o n t h a t t h e l a t e r a l m i g r a t i o n o f water i n f r o z e n g r o u n d h a s a d e t e r - m i n i n g r o l e i n t h e a c c r e t i o n o f i c e t o t h e o l d w e d g e s . T h e s e i n f e r e n c e s h a v e b e e n d i s p u t e d b y V o L k o v a a n d R o m a n o v s k i i ( 1 9 7 4 ) , u p o n t h e b a s i s o f t h e i r e x t e n s i v e i n v e s t i g a t i o n s o f t h e c h e m i c a l c o m p o s i t i o n of u n d e r g r o u n d i c e i n t h e Q u a t e r n a r y d e p o s i t s o f t h e s o u t h e r n p a r t o f t h e Y a n a - I n d i g i r k a l o w l a n d . T h e m i n e r a l i - z a t i o n o f w e d g e i c e v a r i e s f r o m 0 . 0 1 to 0 . 0 5 g r / l a n d t h a t o f s e g r e g a t i o n i c e f r o m 0 . 0 2 t o 0 . 1 3 g r / l . T h e s e d a t a i n d i c a t e t h a t t h e w e d g e i c e i s f o r m e d b y f r e e z i n g o f s u r f a c e w a t e r t h a t h a s a l o w e r m i n e r a l c o n t e n t a n d a m o r e u n i f o r m c o m p o s i t i o n t h a n t he w a t e r o f t h e s e a s o n - a l l y t h a w i n g l a y e r w h i c h f o r m s t h e

6

s e g r e g a t e d i c e a n d e v e n t u a l l y b e c o m e s i n c o r p o r a t e d i n t o p e r m a f r o s t i n a r e a s o f s y n g e n e t i c i c e w e d g e s . C o n s e q u e n t l y , t h e s o u r c e o f w a t e r i s u n l i k e l y t o b e f r o m l a t e r a l m i g r a t i o n . T o m i r d i a r o e t a l . ( 1 9 7 5 ) h a v e s u g g e s t e d t h a t t h e l a r g e P l e i s t o c e n e i c e w e d g e s a r e m o s t l y s u b l i m - i n a l i n o r i g i n , w i t h t h e g r o w t h o f h o a r c r y s t a l s i n t h e c r a c k s , t h e m o i s t u r e s o u r c e b e i n g a t m o s p h e r i c a i r . H o w e v e r , G a s a n o v ( 1 9 7 7 ) d i s a g r e e s w i t h t h e c o n c e p t . H e c o n c l u d e s t h e r e w o u l d b e a v e r t i c a l a i r c o n v e c t i o n i n t h e f r o s t c r a c k s i n w i n t e r w i t h s u b l i m a t i o n a n d t h e r e f o r e r e m o v a l o f i c e f r o m t h e w a l l s o f t h e c r a c k . T h e main s o u r c e o f c r a c k i n f i l l i n g t o f o r m new v e i n l e t s i s s u r f a c e w a t e r f r o m m e l t i n g snow, r a i n , o r r u n o f f . A c c o r d i n g t o G a s a n o v , s u b l i m a t i o n l e a d s o n l y t o a n i n n e r r e d i s t r i b u t i o n w i t h i n t h e c r a c k o f p r e v f - o u s l y f o r m e d v e i n ( c o n g e l a t i o n ) i c e .

D o s t o v a l o v ' s m o d e l ( D o s t o v a l o v 1 9 5 2 ) o f t h e r m a l c o n t r a c t i o n c r a c k i n g a n d t h e s i m p l e d e p e n d e n c e b e t w e e n t h e m e a n a n n u a l t e m p e r a t u r e ( T ) a n d t h e a m p l i t u d e ( A ) o f t h e t e m p e r a u r e a t t h e b a s e o f t h e a c t i v e l a y e r ( T = -1 h a s b e e n u s e d b y K a p l i n a a n d K u z n e t s o v a f 1 9 7 5 ) t o c a l c u l a t e p a s t mean a n n u a l t e m p e r a t u r e s . T h e a u t h o r s c o n c l u d e t h a t r h e o l d P l e i s t o c e n e i c e w e d g e s , w h i c h a r e t h i c k e r t h a n t h o s e o f t o d a y , were f o r m e 2 a t a m e a n a n n u a l t e m p e r a t u r e ( T 5 T ) o f a b o u t - 2 O O C .

B

N u m e r o u s r a d i o c a r b o n d a t e s h a v e b e e n o b t a i n e d i n r e c e n t y e a r s on t h e a g e o f t h e m o s t i n t e n s i v e g r o w t h o f i c e - w e d g e p o l y g o n s i n N o r t h e r n Y a k u t i a . A c c o r d i n g t o r a d i o c a r b o n d a t i n g t h e d e p o s i t s a r e 4 0 , 0 0 0 t o 1 2 , 0 0 0 y e a r s o l d a n d a r e ma.I . r ly o f K a r g i n s k - S a r t a n s k a g e ( K o n i s h c h e v 1 9 7 4 ; T o m i r d i a r o e t a l . 1 9 7 5 ; o t h e r a u t h o r s ) . In t h e w e s t e r n N o r t h A m e r i c a n A r c t i c , s m a l l s y n g e n e t i c P l e i s t o c e n e i c e w e d g e s o f a t l e a s t e a r l y W i s c o n s i n a n a g e ( > 5 0 , 0 0 0 y e a r s ) a r e s t i l l p r e s e r v e d a t H o o p e r I s l a n d , C a n a d a .

P r e s e n t I c e - W e d g e G r o w t h

K a p l i n a ( 1 9 7 6 ) , i n a s t u d y o f t h e s p e c i a l f e a t u r e s o f i c e - w e d g e g r o w t h i n t h e K o l y m a L o w l a n d , U . S . S . R . , h a s f o u n d a d e p e n d e n c e o f g r o w t h r a t e o n g r o u n d t e m p - e r a t u r e . K a p l i n a h a s e s t a b l i s h e d a c o - e f f i c i e n t b e t w e e n t h e w i d t h o f t h e i n c r e - m e n t a l i c e v e i n l e t ( e l e m e n t a r y i c e v e i n l e t ) n e a r t h e t o p o f a n i c e w e d g e t o t h e s i z e o f t h e p o l y g o n . W i t h i n t h e K o l y m a l o w l a n d t h e c o e f f i c i e n t f o r g r o u n d o f s i m i l a r l i t h o l o g y i n c r e a s e s a s t h e m e a n a n n u a l g r o u n d t e m p e r a t u r e d e c r e a s e s , a n d v a r i e s f r o m 0 . 3 t o 1 . 9 m m l m . M e a s u r e m e n t s o f i c e - w e d g e g r o w t h f o r m a n y i c e w e d g e s h a v e b e e n made a t G a r r y I s l a n d , C a n a d a f o r t h e 1 9 7 6 - 1 9 7 8 p e r i o d ( M a c k a y 1 9 7 4 , 1 9 7 5 ) . T h e m e a n a n n u a l a i r a n d g r o u n d t e m p e r a t u r e s a r e -12 'C a n d -8'C r e s p e c t i v e l y . T h e b r o a d

c o n c l u s i o n s a r e : t h e f r e q u e n c y o f i c e - w e d g e c r a c k i n g a v e r a g e s 30 p e r c e n t p e r y e a r w i t h m o s t c r a c k i n g o c c u r r i n g f r o m m i d - J a n u a r y t o m i d - M a r c h ; c r a c k f r e - q u e n c y v a r i e s i n v e r s e l y w i t h s n o w d e p t h ; m e d i u m s i z e d w e d g e s c r a c k t h e most f r e q u e n t l y ; i n s t r u m e n t a t i o n s h o w s t h a t s o m e i c e - w e d g e c r a c k s i n i t i a t e w i t h i n t h e w e d g e s a n d p r o p a g a t e b o t h u p w a r d s a n d d o w n w a r d s ; m e a s u r e m e n t s w i t h p r o b e s p l a c e d w i t h i n t h e c r a c k s show t h a t m o s t c r a c k s c l o s e a p p r e c i a b l y b e f o r e mel twater c a n e n t e r t h e c r a c k s t o g r o w i c e ( e l e m e n t a r y ) v e i n l e t s ; t h e r e i s l i t t l e e v i d e n c e f r o m p r o b e s i n s e r t e d t o t h e b o t t o m o f c r a c k s t o s h o w t h a t t h e c r a c k s p r o g r e s s i v e l y d e e p e n as t h e c o l d w i n t e r t e m p e r a t u r e wave p r o p a g a t e s d o w n w a r d ; a n d i n l o w c e n t r e d p o l y g o n s , t h e r e t e n d s t o b e a n e t o u t w a r d d i s - p l a c e m e n t o f t h e a c t i v e l a y e r m a t e r i a l t o f o r m r i d g e s , t h e m o v e m e n t a v e r a g i n g f r o m 0 . 5 t o 2 mm/yr .

S u b l a c u s t r i n e p o l y g o n s , c o n s i d - e r e d b y S h i l t s a n d Dean ( 1 9 7 5 ) t o b e s i m i l a r to s u b a e r i a l i c e - w e d g e p o l y g o n s , h a v e b e e n d e s c r i b e d f o r l a k e s w h e r e t h e r e i s no e v i d e n c e o f s h o r e l i n e s u b - m e r g e n c e . I f t h e p o l y g o n s h a v e i n d e e d f o r m e d u n d e r w a t e r , i c e - w e d g e c r a c k i n g i s t h e n i n i t i a t e d w i t h i n p e r m a f r o s t r a t h e r t h a n a t t h e l a k e i c e s u r f a c e , b e c a u s e o t h e r w i s e , c r a c k i n g c o u l d n o t r e c u r i n t h e i d e n t i c a l g e o m e t r i c p a t t e r n , y e a r a f t e r y e a r .

I c e - W e d g e P e t r o f a b r i c s

P e t r o f a b r i c s t u d i e s a r e p r o v i n g o f g r e a t a s s i s t a n c e i n t h e u n d e r s t a n d i n g o f t h e m e c h a n i c s o f i c e - w e d g e g r o w t h a n d i n t h e d i f f e r e n t i a t i o n b e t w e e n d i f f e r e n t t y p e s o f g r o u n d i c e . B l a c k ( 1 9 7 8 ) h a s r e p o r t e d o n t h e i c e p e t r o f a b r i c s o f f o u r a c t i v e l y g r o w i n g s u r f a c e w e d g e s a n d n i n e d e e p l y b u r i e d i n a c t i v e w e d g e s n e a r F a i r b a n k s , A l a s k a . L i n e a t i o n s o f o p t i c a x e s were b e t t e r d e v e l o p e d i n t h e s u r f a c e w e d g e s t h a n i n t h e b u r i e d w e d g e s a n d t h e s u r f a c e w e d g e s d i s p l a y e d m o r e c o m p l i - c a r e d f a b r i c s t h a n d i d b u r i e d w e d g e s . T h e r e was e v i d e n c e o f r e c r y s t a l l i z a t i o n o f i c e i n t h e b u r i e d w e d g e s . C e l l ( 1 9 7 8 ) h a s c a r r i e d o u t p e t r o f a b r i c s t u d i e s on i c e w e d g e s o f s e v e r a l t y p e s a n d h a s i n v e s t i g a t e d t h e c h a n g e i n g r a i n s i z e o u t w a r d f r o m t h e c e n t r e o f a w e d g e , i c e a t t h e j u n c t i o n o f t w o w e d g e s , a n d m a s s i v e s e g r e g a t e d i c e c u t b y i c e - w e d g e c r a c k s .

Wedge Cas ts a n d t h e P e r i g l a c i a l R e c o r d

T h e w o r l d d i s t r i b u t i o n o f i c e a n d s o i l w e d g e c a s t s f o r t h e Q u a t e r n a r y i s now r e a s o n a b l y w e l l k n o w n a n d d e t a i l e d r e f e r e n c e s a r e g i v e n b y W a s h b u r n ( i n p r e s s ) . T h e l i t e r a t u r e i s p a r t i c u l a r l y r i c h f o r t h e U . S . S . R . a n d E u r o p e , b u t

7

n u m e r o u s p a p e r s h a v e b e e n p u b l i s h e d f o r o t h e r p a r t s o f t h e w o r l d i n c l u d i n g A r g e n t i n a , t h e B r i t i s h I s l e s , J a p a n a n d N o r t h A m e r i c a . A s i c e - w e d g e p o l y g o n s o n l y g r o w i n a p e r m a f r o s t e n v i r o n m e n t , i d e n t i f i c a t i o n o f i c e - w e d g e c a s t s i s t h e n e v i d e n c e o f p a s t p e r m a f r o s t ( B l a c k 1 9 7 6 ) . I f t h e c r i t e r i a f o r a n i c e - w e d g e o r i g i n a r e u n e q u i v o c a l , t h e n e s t ima tes can b e m a d e o f p a s t t e m p e r a t u r e s . How- e v e r , i t i s v e r y d i f f i c u l t t o e x t r a p o l a t e f r o m p r e s e n t t o p a s t mean a n n u a l a i r o r g r o u n d t e m p e r a t u r e s . Many w r i t e r s c i t e A l a s k a n d a t a ( P E w 6 1 9 7 3 ) w h e r e a c t i v e i c e w e d g e s g r o w i n a r e a s w i t h a mean a n n u a l a i r t e m p e r a t u r e o f a b o u t -6OC o r - 8 O C a n d c o l d e r a n d a s s u m e t h i s t o h o l d f o r o t h e r a r e a s u n d e r d i f f e r e n t c l i m a t i c a n d s o i l C o n d i t i o n s i n t h e g e o - l o g i c p a s t . R o m a n o v s k i i ( 1 9 7 3 ) s t a t e s t h a t i c e v e i n s may form a t g r o u n d t e m p e r - a t u r e s o f - 2 O C a n d c o l d e r , d e p e n d i n g u p o n f a c t o r s s u c h a s s o i l t y p e a n d g e o m o r p h i c c o n d i t i o n s . I n t h e M a c k e n z i e D e l t a , C a n a d a , i c e w e d g e s a r e g r o w i n g on y o u n g a l l u v i a l i s l a n d s w i t h mean a n n u a l g r o u n d t e m p e r a t u r e s o f - 2 t o -3OC w h e r e a s n e a r b y , s o m e o l d i c e w e d g e s r a r e l y c r a c k , e v e n t h o u g h mean a n n u a l g r o u n d t e m p e r a t u r e s a r e - 8 O C . S v e n s s o n ( 1 9 7 7 ) p o i n t s o u t t h a t p o l y g o n a l f r o s t c r a c k i n g now o c c u r s i n n o n - p e r m a f r o s t a r e a s o f N o r d e n . I n a s - much a s m e a n a n n u a l g r o u n d t e m p e r a t u r e s can r a n g e f r o m I t o a t l e a s t 8 ' ~ w a r m e r t h a n m e a n a n n u a l a i r t e m p e r a t u r e s , a n d t h e r m a l c o n t r a c t i o n c r a c k i n g i s n o t l i n e a r l y r e l a t e d t o m e a n a n n u a l a i r t e m p e r a t u r e , g r o u n d t e m p e r a t u r e , o r s o i l t y p e , e x t r a p o l a t i o n f r o m t h e d i m e n s i o n s o f wedge c a s t s t o p a l e o t e m p e r a t u r e s i s d i f f i c u l t .

Wedge Casts a n d t h e G e o l o g i c R e c o r d

In v i e w o f t h e i n d u b i t a b l e e v i d e n c e o f p a s t g l a c i a t i o n i n t h e e a r l y g e o l o g i c r e c o r d , it i s n o t s u r p r i s i n g t h a t s o m e w e d g e - l i k e s t r u c t u r e s , f o u n d i n a s s o c - i a t i o n w i t h t i l l i t e s , h a v e b e e n i n t e r - p r e t e d a s i c e - w e d g e c a s t s a n d t h e r e f o r e i n d i c a t i v e o f p a s t p e r m a f r o s t . T h e g e o l o g i c e v i d e n c e i s d i f f i c u l t t o assess b e c a u s e t h e w e d g e s t r u c t u r e s a r e s m a l l , g o o d p o l y g o n p a t t e r n s h a v e n o t b e e n o b s e r v e d , a n d a w e d g e s t r u c t u r e i s n o p r o o f b y i t s e l f o f p e r m a f r o s t . Y o u n g a n d L o n g ( 1 9 7 6 ) h a v e d e s c r i b e d w e d g e c a s t s , > 2 . 3 b . y . o l d , n o r t h o f E s p a n o l a , O n t a r i o , C a n a d a . T h e w e d g e s were e x p o s e d o n l y i n s e c t i o n , s o i t w a s i m p o s s i b l e t o d e t e r m i n e i f a p o l y g o n a l p a t t e r n was p r e s e n t . I n view o f t h e e v i d e n c e , a n i c e - w e d g e o r i g i n i s q u e s t i o n a b l e . N y s t u e n ( 1 9 7 6 ) d e s c r i b e s a n i c e - w e d g e c a s t f r o m a L a t e P r e c a m b r i a n t i l l i t e i n s o u t h e r n N o r w a y a n d c o m p a r e s t h e c o n d i t i o n s w i t h w e d g e c a s t s s u g g e s t i v e o f p e r m a f r o s t i n t h e P r e c a m b r i a n i n S c o t l a n d , S p i t s b e r g e n , a n d F i n n m a r k . T h e a p p a r e n t w i d t h o f t h e w e d g e i s 5 c m a t t h e

t o p , t h e p r e s u m e d d e p t h i s 70 cm, and t h e a d j a c e n t b e d d i n g i n t h e a d j o i n i n g s a n d s t o n e c o n t a c t i s b e n t s l i g h t l y d o w n w a r d s . T h e f e a t u r e is s o small t h a t i t may h a v e b e e n f o r m e d o n l y b y c r a c k i n g i n a s e a s o n a l l y f r e e z i n g l a y e r a n d t h e r e f o r e d o e s n o t g i v e p r o o f o f p e r m a f r o s r . N a r r o w c l a s t i c d i k e s , g e n e r a l l y l e s s t h a n 1 0 cm I n w i d t h , h a v e b e e n f o u n d w i t h i n t h e b a s a l t i l l i t e o f L a t e O r d o v i c i a n t o E a r l y S i l u r i a n g l a c - i a t i o n s o f S o u t h A f r i c a . D a i l y a n d C o o p e r ( 1 9 7 6 ) r e g a r d t h e d i k e s a s s a n d w e d g e s , g e n e t i c a l l y s imilar t o t he s a n d w e d g e s o f McMurdo S o u n d , A n t a r c t i c a , w h e r e t h e c l i m a t e i s d r y a n d c o l d . H o w e v e r , t h e p o l y g o n a l f o r m s d e s c r i b e d b y D a i l y a n d C o o p e r a r e much sma l l e r t h a n t h o s e o f McMurdo S o u n d , a n d t h e i n t e r s e c t i o n p a t t e r n s a r e a t y p i c a l o f t h e r m a l c o n t r a c t i o n c r a c k s . I n a d d i t i o n , D a i l y a n d C o o p e r a l s o s u g g e s t t h a t a t h r e e - d i m e n s i o n a l c r a c k p a t t e r n i n s a n d s t o n e may b e t h e c a s t o f a r e t i c u l a t e t h r e e - d i m e n s i o n a l i c e v e i n n e t w o r k , s u c h a s f r e q u e n t l y o c c u r s i n f i n e g r a i n e d t i l l s a n d l a k e a n d m a r i n e c l a y s i n p r e s e n t p e r m a f r o s t a r e a s . B u t s u c h r e t i c u l a t e i c e v e i n n e t w o r k s a r e f o u n d i n f i n e g r a i n e d s e d i m e n t s r a t h e r t h a n i n s a n d s ( s a n d s t o n e s ) ,

PINGOS

P i n g o s , a l t h o u g h l o c a l i z e d in d i s t r i b u t i o n , a r e o f i n t e r e s t b e c a u s e p i n g o g r o w t h i s a d y n a m i c r e s p o n s e r o c h a n g e s i n t h e g r o u n d t h e r m a l r e g i m e a n d g r o u n d water h y d r o l o g y . M o r e a n d m o r e s t u d i e s s h o w t h a t p i n g o i c e c a n r a n g e f r o m p u r e i n j e c t i o n i c e , i n j e c t i o n - s e g r e g a t i o n i c e , s e g r e g a t i o n i c e , t o s e g r e g a t i o n i c e i n t e r l a y e r e d w i t h a p r e p o n d e r a n c e o f m i n e r a l a n d / o r o r g a n i c ma t t e r ( E v s e e v 1 9 7 6 ; M a c k a y 1 9 7 7 ; P i s s a r t a n d F r e n c h 1 9 7 7 ; R a m p t o n 1 9 7 4 ) . E v s e e v ( 1 9 7 6 ) i n h i s p a p e r on t h e m a i n c h a r a c - t e r i s t i c s , o c c u r r e n c e s , a g e s , a n d c r y o - g e n i c s t r u c t u r e s o f p i n g o s i n t h e E u r o p e a n p a r t o f t h e U.S . S . R . a n d W e s t e r n S i b e r i a , d i s c u s s e s s e g r e g a t i o n i c e i n t h e p i n g o s .

P i n g o G r o w t h

F i e l d s t u d i e s o n B a n k s I s l a n d , W e s t e r n C a n a d i a n A r c t i c ( P i s s a r t a n d F r e n c h 1 9 7 7 ) s h o w t h a t s o m e p i n g o s h a v e g r o w n o n l o w t e r r a c e s f o l l o w i n g t h e l a t e r a l m i g r a t i o n o f a r i v e r c h a n n e l a n d t h e f r e e z i n g o f a t a l i k w h i c h h a d f o r m e d b e n e a t h t h e c h a n n e l . On P r i n c e P a t r i c k I s l a n d , C a n a d a , e l o n g a t e p i n g o s l o c a t e d n e a r t h e c o a s t a r e b e l i e v e d t o h a v e f o r m e d f o l l o w i n g f l u c t u a t i o n s o f s ea l e v e l a n d t h e i n u n d a t i o n o f r i v e r v a l l e y s . O t h e r p i n g o s i n t h e c e n t r a l p a r t s o f P r i n c e P a t r i c k I s l a n d a p p e a r

8

r e l a t e d t o t h e p r e s e n c e o f d e e p f a u l t s f r o m g l a c i a l , t h e r m o k a r s t , e o l i a n , a n d i n t h e u n d e r l y i n g b e d r o c k a t a t ime a n t h r o p o g e n i c c a u s e s . T h e r e c o g n i t i o n o f w h e n p e r m a f r o s t was a g g r a d i n g . K o w a l k o w s k i p i n g o r e m n a n t s , i n f o r m e r p e r i g l a c i a l ( 1 9 7 8 ) h a s a l s o d e s c r i b e d p i n g o s , w i t h i c e a r e a s , i s w i d e s p r e a d ( e g . B a s t i n e t a l . l e n s e d c o r e s w h i c h h a v e f o r m e d i n a b a n - 1 9 7 4 ; C a i l l e u x 1 9 7 6 ; F l e m a l 1 9 7 6 ; S v e n s s o n d o n e d c h a n n e l s i n a b a s i n o f t h e K h a n g a i 1 9 7 6 ; W a t s o n 1 9 7 6 ) . Many o f t h e i d e n t i f i - M o u n t a i n s , M o n g o l i a . c a t i o n s h a v e b e e n b a s e d u p o n d e t a i l e d

P i n g o s i n b e d r o c k a r e f r e q u e n t l y r e p o r t e d i n t h e l i t e r a t u r e ( e g . Ahman 1 9 7 3 B a l k w i l l e t a l . 1 9 7 4 ) . T h e p i n g o s a r e o f b o t h c l o s e d a n d o p e n s y s t e m t y p e s a n d b e d r o c k h a s b e e n domed 35 t o 4 0 m a b o v e t h e s u r r o u n d i n g g r o u n d l e v e l , s o t h e u p - l i f t p r e s s u r e s h a v e b e e n c o n s i d e r a b l e . A s e x t e n s i v e i c e s e g r e g a t i o n i s u n l i k e l y t o o c c u r i n b e d r o c k , i n j e c t i o n i c e c o r e s c a n b e i n f e r r e d f o r p i n g o s w i t h a b e d r o c k o v e r b u r d e n . I n a n e n d e a v o r t o d e t e r m i n e t h e c h a r a c t e r i s t i c s o f p i n g o w a t e r s , a d e t a i l e d s t u d y ( A l l e n e t a l . 1 9 7 6 ) h a s b e e n c a r r i e d o u t o n w a t e r s i n S c o r e s b y L a n d , n o r t h e a s t G r e e n l a n d . S a m p l e s o f d i f f e r e n t w a t e r s ( e g . g l a c i e r , s t r eam, p i n g o ) were a n a l y z e d c h e m i c a l l y f o r t h e i r p r i n c i p a l s o l u t e i o n s , a n d i s o t o p i c a l l y f o r t h e i r d e u t e r i u m a n d o x y g e n i s o t o p e c o n t e n t s . I t was c o n c l u d e d t h a t a l l o f t h e w a t e r s f r o m t h e p i n g o s a r e o f r e c e n t m e t e o r i c o r i g i n .

T h e g r o w t h of p i n g o s a l o n g t h e W e s t e r n C a n a d i a n A r c t i c c o a s t h a s b e e n m e a s u r e d b y p r e c i s e l e v e l l i n g ( 1 9 6 9 - 1 9 7 8 ) o f b e n c h m a r k s i n s t a l l e d i n t o p e r m a f r o s t ( M a c k a y 1 9 7 7 ) . D r i l l i n g h a s s h o w n t h a t t h e h y d r o s t a t i c h e a d o f a g r o w i n g c l o s e d s y s t e m p i n g o may r i s e f a r h i g h e r t h a n t h e t o p o f t h e p i n g o . P r e s s u r e t r a n s d u c e r s , i n s t a l l e d b e n e a t h a g g r a d i n g p e r m a f r o s t s u r r o u n d i n g g r o w i n g p i n g o s , s h o w t h a t t h e p o r e w a t e r p r e s s u r e s g e n e r a t e d b y p o r e w a t e r e x p u l s i o n c a n e x c e e d 8 0 p e r c e n t o f t h e t o t a l o v e r b u r d e n p r e s s u r e , e v e n b e n e a t h p e r m a f r o s t 4 0 m t h i c k . D r i l l i n g h a s a l s o s h o w n t h e p r e s e n c e o f l a r g e s u b p i n g o water l e n s e s a s much as 2 . 2 m d e e p a n d w i t h b a s a l d i a m e t e r s o f up t o 300 m ( M a c k a y 1 9 7 8 ) . T h e r e i s some f i e l d e v i d e n c e t o s u g g e s t t h a t t h e r e may b e d o w n s l o p e c r e e p o f t h e o v e r b u r d e n a n d i c e c o r e o f s o m e o f t h e o l d e r a n d l a r g e r p i n g o s . Two t h e o r i e s h a v e r e c e n t l y b e e n p r o p o s e d f o r t h e o r i g i n o f p i n g o s . B l e i c h ( 1 9 7 4 ) s u g g e s t s t h a t a p i n g o g r o w s w i t h a w a t e r s u p p l y f r o m a l a k e f e d t h r o u g h i c e - w e d g e c r a c k s . R y c k b o r s t ( 1 9 7 4 ) b e l i e v e s p i n g o s o r i g i n a t e a s u p w a r d - g r o w i n g i c e l e n s e s a b o v e t h e water t a b l e i n t h e a c t i v e l a y e r i n u n s a t u r a t e d s a n d . H o w - e v e r , b o t h t h e o r i e s a r e c o n t r a d i c t e d b y a b u n d a n t f i e l d d a t a .

P i n g o S c a r s

The i d e n t i f i c a t i o n o f t h a w e d p i n g o s i s d i f f i c u l t , b e c a u s e c i r c u l a r f o r m s w i t h r a m p a r t s may a l s o r e s u l t f r o m o t h e r p r o c e s s e s t h a n p i n g o c o l l a p s e , e g .

m a p p i n g o f t h e s t r a t i g r a p h y , s t ~ u c t u r e a n d p a l y n o l o g y o f r i n g e d d e p r e s s i o n s . A s

from t h e l o w e r P a l e o z o i c i n t h e S a h a r a d e s e r t , p i n g o s c a r s , l i k e i c e - w e d g e c a s t s , c a n c o n t r i b u t e t o o u r u n d e r s t a n d i n g o f t h e g e o l o g i c r e c o r d .

: p i n g o - l i k e r e m n a n t s h a v e b e e n r e c o g n i z e d

PALSAS

T h e m a j o r f o c u s o f p a l s a r e s e a r c h c o n t i n u e s t o b e t h e l i f e c y c l e o f p a l s a s ; w h e t h e r p a l s a s a r e f o r m e d b y i c e i n j e c t i o n o r i c e s e g r e g a t i o n ; a n d w h e t h e r t h e f e a - t u r e s a r e e s s e n t i a l l y d e g r a d a t i o n a l o r a g g r a d a t i o n a l i n o r i g i n ( J a h n 1 9 7 6 ; S e p p a l a 1 9 7 6 ) . Ahman ( 1 9 7 7 ) , i n a d e t a i l - e d p a l s a i n v e s t i g a t i o n i n P e n n o s c a n d i a , h a s c l a s s i f i e d t h e m i n t o p a l s a p l a t e a u s , e s k e r p a l s a s , s t r i n g p a l s a s , d o m e - s h a p e d p a l s a s , a n d p a l s a c o m p l e x e s . T h e p r i m a r y p r e r e q u i s i t e f o r p a l s a f o r m a t i o n a c c o r d - i n g t o Ahman i s a s o i l s u i t a b l e for i c e s e g r e g a t i o n . G e n e t i c a l l y , n o d i f f e r e n c e w a s f o u n d i n t h e s t a r t i n g p o i n t o r f u r t h e r d e v e l o p m e n t o f a p u r e p e a t p a l s a o n o n e e x t r e m e t o t h a t o f a p u r e m i n e r a l s o i l p a l s a a t t h e o t h e r e x t r e m e . A c c o r d i n g t o t h i s v i e w , a p a l s a i s a h i l l o c k f o r m e d b y s e g r e g a t e d i c e i n s o i l , p e a t , or a c o m b i n a t i o n o f t h e m .

G E O C H E M I S T R Y OF GROUND ICE

T h e g e o c h e m i s t r y o f ground i c e , i n c l u d i n g t h e u s e o f s t a b l e i s o t o p e s , a p p e a r s t o b e a p r o m i s i n g r e s e a r c h f i e l d f o r t h e s t u d y o f i c e l e n s i n g , t h e g r o w t h of p e r m a f r o s t , h y d r a u l i c c o n d u c t i v i t y o f f r o z e n s o i l s , c h a n g e s i n t h e t h i c k n e s s o f t h e a c t i v e l a y e r , a n d i n p a l e o c r y o l o g i c r e c o n s t r u c t i o n s o f p a s t e n v i r o n m e n t s ( A n i s i m o v a 1 9 7 8 ) . H a l l e t ( 1 9 7 8 ) d i s c u s s e s s o m e o f t h e p r o b l e m s o f r e d i s t r i b u t i o n o f s o l u t e s i n f r e e z i n g s o i l s o l u t i o n s a n d p o i n t s o u t t h a t t h e r e a r e i m p l i c a t i o n s o n t h e n u c l e a t i o n o f i c e l e n s e s , t h e r h y t h m i c s p a c i n g o f i c e l e n s e s , a n d t h e h e a v i n g c h a r a c t e r i s t i c s o f t h e s o i l . O x y g e n i s o t o p e r a t i o s h a v e b e e n u s e d to p r o v i d e p a L e o c l i m a t i c i n f o r m a t i o n a n d c h r o n o l o g y o f t h r e e c o r e s f r o m A n t a r c t i c a ( S t u i v e r e t a l . 1 9 7 6 ) . A l t h o u g h t h e i n t e r p r e t a t i o n o f t h e o x y g e n i s o t o p e r e c o r d f r o m p e r m a f r o s t i s m o r e c o m p l i c a t e d t h a n f o r g l a c i e r i c e c o r e s , b e c a u s e t h e a c c u m u - l a t i o n o f s e d i m e n t s i s n o t n e c e s s a r i l y c o n t i n u o u s , a n d a p o r t i o n o f t h e l 8 0 r e c o r d may b e m i s s i n g b e c a u s e o f r e p l a c e - m e n t b y y o u n g e r wa te r s o r for o t h e r

9

r e a s o n s , t h e A n t a r c t i c r e c o r d s h o w s g r e a t p r o m i s e , M i c h e l a n d F r i t z ( 1 9 7 8 ) h a v e s t u d i e d o x y g e n i s o t o p e r a t i o s f o r s e d i - ments i n t h e M a c k e n z i e V a l l e y , C a n a d a a n d h a v e i n t e r p r e t e d t h e m o r e n e g a t i v e v a l u e s a t d e p t h a s r e f l e c t i n g d e e p i n - a c t i v e p e r m a f r o s t p o s s i b l y a s much as 7 , 0 0 0 t o 1 0 , 0 0 0 y e a s o l d . T h e y c o n s i d e r t h a t t r i t i u m a n d "0 d a t a c a n b e u s e d t o d i s t i n g u i s h b e t w e e n a c t i v e a n d i n a c t i v e ( r e l i c ) p e r m a f r o s t . V a n E v e r d i n g e n ( 1 9 7 8 ) h a s u s e d o x y g e n - a n d s u l p h u r i s o - t o p e s a n d water q u a l i t y a n a l y s e s t o s t u d y t h e s o u r c e o f w a t e r a n d f r e e z i n g p r o c e s s e s o f f r o s t b l i s t e r s near F o r t N o r m a n , N . W . T . , C a n a d a .

THERMOKARST

S i n c e t h e r m o k a r s t f e a t u r e s r e f l e c t n a t u r a l c h a n g e s , w h e t h e r g e o m o r p h i c , c l i m a t i c , o r v e g e t a t i o n a l , a s t u d y o f t h e r m o k a r s t i s a s t u d y o f c h a n g e ( B r o w n 1 9 7 4 ; F r e n c h 1 9 7 4 ; R a m p t o n 1 9 7 4 ; S h u r 1 9 7 4 ; U g o l i n i 1 9 7 5 ) . O n e a s p e c t o f r e c e n t r e s e a r c h h a s b e e n t h e m a p p i n g o f t h e r m o - k a r s t f e a t u r e s o v e r l a r g e a r e a s by means o f r e m o t e s e n s i n g i m a g e r y . S e l l m a n e t a l . ( 1 9 7 5 ) h a v e s t u d i e d t h a w l a k e s o n t h e A r c t i c C o a s t a l P l a i n , A l a s k a u s i n g s e q u e n - t i a l s a t e l l i t e i m a g e r y b y m e a n s o f w h i c h , f o r e x a m p l e , l a k e d e p t h s c o u l d b e e s t i - m a t e d f r o m t h e e x t e n t o f i c e c o v e r , a n d d e d u c t i o n s m a d e o n g r o u n d i c e v o l u m e s a n d b a s i n g e n e s i s . I n Q u e b e c , C a n a d a , T h i b o d e a u x a n d C a i l l e u x ( 1 9 7 3 ) h a v e m a p p e d t h e r m o k a r s t t e r r a i n o v e r v e r y l a r g e a r e a s u s i n g a i r p h o t o g r a p h s . F e a t u r e s s u c h a s c i r c u l a r l a k e s , b e a d e d s t reams a n d s t r i n g b o g s , p r e s u m a b l y o f t h e r m o k a r s t o r i g i n , were s h o w n t o v a r y a l o n g n o r t h - s o u t h s a m p l i n g a r e a s . On a n i n t e r p l a n e t a r y s c a l e , G a t t o a n d A n d e r s o n ( 1 9 7 5 ) h a v e c o m p a r e d a n A l a s k a n t h e r m o k a r s t t e r r a i n w i t h a p o s s i b l e t h e r m o k a r s t a n a l o g o n t h e p l a n t Mars.

Gravis ( 1 9 7 8 ) , f r o m r a d i o c a r b o n d a t i n g o f a l a s , a l l u v i a l , a n d m a r i n e d e p o s i t s o f t he same a g e , t o g e t h e r w i t h p a l y n o l o g i c a l d a t a , s h o w s t h a t m o s t t h e r m o k a r s t d e p r e s s i o n s o n t h e Marit ime P l a i n a n d N o v o s i b i r s k I s l a n d s , U . S . S . R . , a r e o f p r e - H o l o c e n e a g e . T h e r m o k a r s t o c c u r r e d m a i n l y d u r i n g c o l d g l a c i a l e p o c h s ( Z y r a n a n d S a r t a n ) a n d c o i n c i d e d w i t h a l o w e r e d s ea l e v e l . S h u r ( 1 9 7 4 ) h a s c o n c l u d e d t h a t a t p r e s e n t t h e r m o k a r s t i s f o r m e d m o s t l y a s a r e s u l t o f l o c a l c o n d i t i o n s o f h e a t e x c h a l g e in t h e s y s t e m ( s o i l , u n d e r g r o u n d i c e , e n v i r o n m e n t ) a n d c h a n g e s i n t h e c l i m a t e may e i t h e r a c c e l e r - a t e o r r e t a r d t h e r m o k a r s t d e v e l o p m e n t . V e l i k o t s k y ( 1 9 7 4 ) h a 3 p r e s e n t e d d a t a w h i c h show a r e l a t i o n b e t w e e n t e c t o n i c j o i n t i n g i n t h e n o r t h o f t h e Y a n a - O m o l o i i n t e r f l u v e , U.S.S.R., a n d t h e d e v e l o p m e n t of t h e r m o - k a r s t ( a l a s ) f o r m s o f r e l i e f . Ramp t o n

( 1 9 7 4 ) b e l i e v e s t h a t m a n y o f t h e t h e r m o k a r s t f e a t u r e s o f t h e W e s t e r n A r c t i c C o a s t , C a n a d a h a v e d e v e l o p e d d u r i n g t h e p o s t g l a c i a l warm p e r i o d w h i c h c u l m i n a t e d a b o u t 8 , 0 0 0 y e a r s a g o . R a m p t o n a n d W a l c o t t ( 1 9 7 4 ) h a v e u s e d g r a v i t y p r o f i l e s a c r o s s i c e - c o r e d t o p o g r a p h y t o d e t e r m i n e t h e a m o u n t o f e x c e s s i c e a n d p r o b a b l e t h e r m o k a r s t s u b s i d e n c e i f t h e a r e a were t h a w e d .

REGIONAL G E O C R Y O L O G Y

A l p i n e P e r m a f r o s t

A l p i n e p e r m a f r o s t w i t h l i m i t e d a m o u n t s o f g r o u n d i c e e x i s t s i n many t e m p e r a t e m o u n t a i n o u s a r eas o f t h e n o r t h e r n a n d s o u t h e r n h e m i s p h e r e a n d even i n t h e t r o p i c s , s u c h as H a w a i i (Woodcock 1 9 7 4 ) . F u j i i a n d H i g u c h i ( 1 9 7 8 ) h a v e a t t e m p t e d t o map t h e d i s t r i b u t i o n o f a l p i n e p e r m a f r o s t i n t h e n o r t h e r n h e m i - s p h e r e a n d h a v e s u g g e s t e d t h a t t h e l o w e r limit o f a l p i n e p e r m a f r o s t c o r r e s p o n d s t o t h e a l t i t u d e w h e r e t h e m e a n a n n u a l a i r t e m p e r a t u r e i s i n t h e r a n g e o f -1 t o -3OC. A l t h o u g h s u c h a c o r r e l a t i o n b e t w e e n mean a n n u a l a i r t e m p e r a t u r e a n d p e r m a f r o s t may e x i s t i n some a r e a s , o t h e r f a c t o r s , p a r t i c u l a r l y s n o w c o v e r ( H a e b e r l i 1 9 7 8 1 , make c o r r e l a t i o n b e t w e e n m e a n a n n u a l a i r t e m p e r a t u r e s a n d p e r m a f r o s t d i s t r i b u t i o n o n a w o r l d s c a l e d i f f i c u l t .

C o n s i d e r a b l e r e s e a r c h h a s b e e n c a r r i e d o u t o n a l p i n e p e r m a f r o s t i n t h e P a r n i r a n d T i e n S h a n . G o r b u n o v ( 1 9 7 6 , 1 9 7 8 ) h a s f o u n d s o m e r e g u l a r i t y i n t h e f o r m a t i o n o f p e r m a f r o s t a n d t h e c r y o g e n i c s t r u c t u r e s i n m o u n t a i n e n v i r o n m e n t s . G o r b u n o v h a s d i s t i n g u i s h e d t h r e e m a i n t y p e s o f l a y e r e d p e r m a f r o s t i n m o u n t a i n - o u s a r e a s o f t h e w o r l d , n a m e l y a s i n g l e - l a y e r o f p e r m a f r o s t ( t h a w i n g a n d d e g r a d - i n g ) ; t w o - l a y e r e d p e r m a f r o s t ( t h a w i n g a n d f r o z e n ) ; a n d a g g r a d i n g p e r m a f r o s t ( s i n g l e - l a y e r e d ) . T h e e x t e n t t o w h i c h G o r b u n o v ' s t h r e e m a i n t y p e s o c c u r e l s e w h e r e i n a l p i n e r e g i o n s s t i l l n e e d s f i e l d c o n f i r m a t i o n .

I n v e s t i g a t i o n s o f a l p i n e p e r m a - f r o s t i n t h e C a n a d i a n Rocky M o u n t a i n s b y Harris a n d B r o w n ( 1 9 7 8 ) s h o w t h a t p e r m a - f r o s t may e x t e n d t o a d e p t h o f 1 0 0 m o r m o r e , t h e u p p e r p o r t i o n h a v i n g a d j u s t e d t o t h e p r e s e n t c l i m a t e a n d t h e l o w e r l a y e r b e i n g r e l i c . B o c k g l a c i e r s ( B a r s c h 1 9 7 8 ; C o r t e 1 9 7 8 ) a r e a l s o l o c a l i n d i - c a t o r s o f p e r m a f r o s t . I n g e n e r a l , e x c e p t f o r t h e i c e i n r o c k g l a c i e r s , g r o u n d i c e i n a r e a s o f a l p i n e p e r m a f r o s t is p r o b a b l y n e g l i g i b l e b e c a u s e o f t h e a b u n d a n c e o f b e d r o c k a t d e p t h .

10

S u b m a r i n e P e r m a f r o s t

C o n s i d e r a b l e p r o g r e s s h a s b e e n made i n t h e d e l i n e a t i o n a n d n a p p i n g o f s u b m a r i n e ( o f f s h o r e ) p e r m a f r o s t s i n c e 1 9 7 3 b u t c o m p a r a t i v e l y l i t t l e i s known a b o u t t h e c o n t a i n e d g r o u n d i c e . A c c o r d i n g t o Are ( 1 9 7 6 , 1 9 7 8 ) o f f s h o r e p e r m a f r o s t e x t e n d s o v e r t h e g r e a t e r p a r t o f t h e s h e l f o f Asia a n d t h e A r c t i c B a s i n . H e h a s i d e n t i f i e d t w o z o n e s o v e r t h e b o t t o m o f t h e A r c t i c B a s i n , v i z . a d e e p w a t e r z o n e w i t h t e m p e r a t u r e s b e l o w D O C a n d a z o n e b e t w e e n 200 a n d 9 0 0 m w i t h wa te r s a b o v e O ° C . T h e s e a w a t e r t e m p e r a t u r e i n t h e a b y s s a l t r o u g h s i t u a t e d b e t w e e n t h e L o m o n s o v R i d g e a n d t h e B a r e n t s - K a r a s h e l f i s a t a b o u t - 0 . 7 t o - l . O ° C , t h i s s u g g e s t i n g p e r m a f r o s t u n d e r t h e b o t t o m o f t h e t r o u g h . T h e b o t t o m d e p o s i t s p r o b a b l y d o n o t c o n t a i n i c e , i . e . t h e d e p o s i t s a r e n o t i c e - b o n d e d . P e r m a f r o s t , a c c o r d i n g t o A r e , i s a b s e n t i n t h e u p p e r p o r t i o n o f t h e c o n t i n e n t a l s l o p e , i n t h e d e e p e s t p a r t s o f t h e a r c t i c s e a s , a n d p r o b a b l y a l s o i n t h e z o n e o f w a r m i n g o f l a r g e r i v e r s w h e r e d e p t h s a r e l e s s t h a n 2 0 m . R e l i c p e r m a f r o s t c a n o c c u r i n t h a t p a r t o f t h e s h e l f w h i c h w a s e x p o s e d d u r i n g t h e l a s t g l a c i a l s ea l e v e l l o w e r i n g . I n t h e s e a r e a s , g r o u n d i c e m i g h t o c c u r a t d e p t h a s i t d o e s i n s o m e n e a r b y l a n d a r e a s . D e t a i l e d l a r g e - s c a l e s t u d i e s o f s u b m a r i n e p e r m a f r o s t o f t h e V a n k i n a Guba (Bay) i n t h e L a p t e v Sea s h o w t h a t t h e p e r m a f r o s t c o n d i t i o n s a r e c o m p l e x ( Z h i g a r e v a n d P l a k h t 1 9 7 4 ) . K u d r y a v t s e v e t a l . ( 1 9 7 8 ) g i v e a map s h o w i n g s u b m a r i n e p e r m a f r o s t f o r E u r a s i a . N u m e r o u s i n v e s t i g a t i o n s h a v e b e e n c a r r i e d o u t on o f f s h o r e p e r m a f r o s t a l o n g t h e N o r t h A m e r i c a n W e s t e r n A r c t i c C o a s t ( e g . H u n t e r e t a l . 1 9 7 8 ; I s k a n d a r e t a l . 1 9 7 8 ) . S e i s m i c a n d d r i l l i n g r e c o r d s h a v e s h o w n t h a t i c e - b o n d e d p e r m a f r o s t may o c c u r b e n e a t h non i c e - b o n d e d s e d i m e n t s w h o s e s a l i n e p o r e w a t e r i s b e l o w O ° C . I n s o m e a r e a s , i n i t i a l l y i c e - b o n d e d p e r m a f r o s t h a s h a d t h e i n t e r s t i t i a l f r e s h - w a t e r i c e d i s s o l v e d b y s a l i n e w a t e r a t a n e g a t i v e t e m p e r a t u r e ( I s k a n d a r e t a l . 1 9 7 8 ) .

PALEOCRYOLOGLCAL STUDIES

P a l e o c r y o l o g i c s t u d i e s h a v e b e e n d e v e l o p e d t o t h e g r e a t e s t e x t e n t i n t h e U.S.S.B. I n N o r t h A m e r i c a , a s u b s t a n t i a l p e r c e n t a g e o f t h e a r e a now w i t h p e r m a f r o s t w a s b e n e a t h g l a c i e r i c e o n l y 1 5 , 0 0 0 y e a r s a g o a n d s i n c e n e a r s u r f a c e b e d r o c k i s w i d e s p r e a d , o l d u n d e r g r o u n d i c e i s n e c e s s - a r i l y d i f f i c u l t t o i d e n t i f y o r g e n e r a l l y a b s e n t . T h e h i s t o r y o f p e r m a f r o s t i n t h e e a s t e r n p a r t o f t h e B o l s h e z e m e l s k a y a T u n d r a , U . S . S . R . , a n d t h e r e l a t i o n b e t w e e n t h e c r y o g e n i c s t r u c t u r e a n d t h e t h e r m a l r e g i m e o f p e r m a f r o s t h a s b e e n s t u d i e d b y T u m e l ( 1 9 7 7 ) . S h e h a s d r a w n i n t e r e s t i n g c o n c l u s i o n s on t h e l o n g t e r m e f f e c t o f t h e t h e r m a l r e g i m e o f t h e g r o u n d o n t h e f a b r i c

o f g r o u n d i c e ( c r y o g e n i c s t r u c t u r e ) i n p e r m a f r o s t i n t h e r e g i o n . T h e p a l e o - c r y o g e n i c r e c o n s t r u c t i o n s h o w s t h a t p e r m a f r o s t g r e w i n t h e p a s t i n d i f f e r e n t s u b s u r f a c e mater ia l s b u t u n d e r s imilar g r o u n d t h e r m a l r e g i m e s . Hence t h e e p i g e n e t i c a l l y f r o z e n p e r m a f r o s t a l t h o u g h o f d i f f e r e n t a g e s h a s a similar c o m p o s i - t i o n , w a t e r c o n t e n t , a n d c r y o g e n i c f a b r i c . T u m e l h a s a l s o s h o w n t h a t t h e a s s o c i a t i o n o f t h e c r y o g e n i c f a b r i c o f t h e u p p e r p a r r o f p e r m a f r o s t w i t h t h e m o d e r n mean a n n u a l g r o u n d t e m p e r a t u r e a t t h e d e p t h o f z e r o a n n u a l t e m p e r a t u r e c h a n g e o r w i t h o t h e r m o d e r n t e m p e r a t u r e v a l u e s i s a b s e n t i n t h e s u r f a c e l o a m s o f t h e B o l s h e z e m e l s k a y a T u n d r a .

G r a v i s e t a l . ( 1 9 7 4 ) i n a r e c e n t l y c o - a u t h o r e d p u b l i c a t i o n o n " G e n e r a l G e o c r y o l o g y " h a s d i s c u s s e d t h e p r o c e s s e s o f i c e s e g r e g a t i o n o f f i n e - g r a i n e d s o i l s u n d e r c o n d i t i o n s o f e p i g e n e t i c f r e e z i n g . He d i s t i n g u i s h e s t h r e e h o r i z o n s o f i c e f o r m a t i o n w h i c h a r e , f r o m t o p t o b o t t o m : 1 ) t h e h o r i z o n o f i c e f o r m a t i o n w i t h i c e l e n s e s ( c r y o g e n i c f a b r i c o f a s e g r e g a - t i o n a l t y p e ) w h e r e t h e water w h i c h m i g r a t e s t o t h e f r e e z i n g f r o n t i s u n d e r a s u c t i o n ; 2 ) t h e h o r i z o n o f i c e f o r m a t i o n w i t h i n j e c t i o n o r i n t r u s i v e i c e ( c r y o g e n i c f a b r i c o f a n i n j e c t i o n t y p e ) w h e r e t h e w a t e r w h i c h m i g r a t e s t o w a r d s t h e f r e e z i n g f r o n t i s u n d e r p r e s s u r e ; a n d 3 ) t h e h o r i z o n o f p a s s i v e i c e f o r m a t i o n w i t h t h e c r y o g e n i c f a b r i c r e f l e c t i n g t h a t o f t h e h o s t m a t e r i a l * A c c o r d i n g t o G r a v i s , i f t h e r e a r e s e v e r a l d e e p - l y i n g w a t e r b e a r i n g h o r i z o n s w i t h w a t e r u n d e r p r e s s u r e , s e v e r a l h o r i z o n s w i t h c r y o g e n i c f a b r i c s o f a n i n j e c t i o n a l t y p e w i l l b e f o r m e d . T h e t h r e e h o r i z o n s , d i s c u s s e d b y G r a v i s , were o b s e r v e d b y h i m i n M o n g o l i a ( G r a v i s 1 9 7 4 ) . T h e e x t e n t t o w h i c h t h e t h r e e h o r i z o n s c a n b e r e c o g - n i z e d e l s e w h e r e remains t o b e d e t e r m i n e d . F o r e x a m p l e , t h e o c c u r r e n c e o f h o r i z o n two i s p r o b a b l y a b s e n t i n many r e g i o n s w h e r e n o b u i l d u p o f w a t e r p r e s s u r e was p o s s i b l e . K a t a s o n o v ( 1 9 7 5 ) h a s a t t e m p t e d t o a s s o c i a t e t h e c o n t e m p o r a n e o u s c r y o g e n i c f o r m s o f r e l i e f w i t h t h e g e n e s i s o f u n d e r g r o u n d i c e a n d t h e e n c l o s i n g d e p o s i t s .

S t u d i e s o f t h e r e l i e f f e a t u r e s d u e t o u n d e r g r o u n d i c e ( c r y o g e n i c f o r m s o f r e l i e f ) i n t h e a r e a o f o l d p e r m a f r o s t ( p a l e o c r y o g e n i c a r e a ) o f t h e R u s s i a n P l a i n h a v e c o n t i n u e d to d e v e l o p . B e r d n i - k o v ( 1 9 7 6 ) h a s d i s c u s s e d i n d e t a i l t h e g e o m o r p h o l o g i c a l c h a r a c t e r i s t i c s o f t h e r e l i c c r y o g e n i c r e l i e f i n t h e U p p e r V o L g a B a s i n a n d h e h a s d i s c u s s e d s o m e c h a r a c - t e r i s t i c f e a t u r e s o f t h e m o r p h o l o g y o f w e d g e - l i k e f e a t u r e s a n d a s y m m e t r i c a s p e c t s o f t h e i r s t r u c t u r e . K o r e i s h a ( 1 9 7 6 ) h a s s h o w n t h e i m p o r t a n c e o f p a l e o g r a p h i c a l r e s e a r c h i n h i s a n a l y s i s o f t h e g r o u n d i c e i n t h e e x t r e m e N o r t h e a s t

a r e a o f t h e U . S . S . R . w h e r e t h e c o n c e n t r a - t i o n o f u n d e r g r o u n d i c e i s t h e g r e a t e s t f o r t h e e n t i r e p e r m a f r o s t a r e a o f E u r a s i a . T h e N o r t h e a s t a r e a c o m p r i s e s o n l y 2 5 p e r - c e n t o f t h e w h o l e p e r m a f r o s t z o n e b u t u p t o 4 0 p e r c e n t o f t h e t o t a l u n d e r g r o u n d i c e i s c o n c e n t r a t e d t h e r e . T h i s i s a r e g i o n w h e r e t h e g r e a t r a n g e a n d c l o s e i n t e r - r e l a t i o n s h i p s o f d i f f e r e n t u n d e r g r o u n d . i c e t y p e s ( v e i n e d , s e g r e g a t i o n , a n d i n j e c t i o n ) a n d s u r f a c e i c e t y p e s ( i c i n g s , g l a c i e r s , e r c . ) a r e e x p o s e d t h e m o s t v i v i d l y , K o r e i s h a h a s s h o w n , i n a g e n e r a l w a y , t h e r e l a t i o n s h i p b e t w e e n u n d e r g r o u n d a n d s u r f a c e i c e o f t h e Nor t h e a s t a n d t h e c l imare , a l t i t u d i n a l z o n e s , a n d t e c t o n i c d e v e l o p m e n t .

T h e r e c o n s t r u c t i o n o f p a l e o c l i m a t e f r o m p r e s e n t d a y g e o t h e r m a l d a t a c a n b e o f c o n s i d e r a b l e a s s i s t a n c e t o p a l e o c r y o l o g i c a l s t u d i e s ( B a l o b a e v 1 9 7 8 ; S h a r b a t y a n a n d S h u m s k i y 1 9 7 4 ) . By u s i n g g e o t h e r m a l d a t a f o r d i s e q u i l l b r l u m p e r m a f r o s t t h a w i n g f r o m b e l o w , B a l o b a e v ( 1 9 7 8 ) h a s c o n c l u d e d t h a t d u r i n g t h e l a s t c o l d p e r i o d ( g l a c i a t i o n ) i n t h e n o r t h e r n p a r t o f t h e A s i a t i c c o n t i n e n t , a b o u t 2 0 , 0 0 0 y e a r s a g o , t h e c l i m a t e w a s c o l d e r b y a b o u t lo to 13OC.

C R Y O G E N I C W E A T H E R T N E

One o f t h e m o s t i m p o r t a n t p r o b l e m s i n v o l v i n g i c e o n a m i c r o s c a l e i s t h e d e g r e e t o w h i c h t h e r e a r e c o m p o s i t i o n a l a n d t e x t u r a l c h a n g e s i n d i f f e r e n t t y p e s o f m a t e r i a l s w h e n t h e y u n d e r g o f r e e z e a n d t h a w . A s e c o n d a n d r e l a t e d p r o b l e m i s t h e d e g r e e t o w h i c h c h a n g e s may t a k e p l a c e t h r o u g h g e o l o g i c t ime a t b e l o w O°C temp- e r a t u r e s . I n f i n e - g r a i n e d s o i l s w h i c h can h a v e c o n s i d e r a b l e u n f r o z e n p o r e w a t e r b e l o w O°C, t e m p e r a t u r e f l u c t u a t i o n s I n t h e b e l o w O°C t e m p e r a t u r e r a n g e c a n c a u s e c h a n g e s i n t h e c r y o g e n i c f a b r i c , i c e j w a t e r c o n t e n t , f r o s t h e a v e , a n d h y d r a u l i c c o n - d u c t i v i t y . K o n l s h c h e v ( 1 9 7 7 , 1 9 7 8 ) h a s i n v e s t i g a t e d t h e i n t e r a c t i o n o f w a t e r w i t h d i f f e r e n t s t r u c t u r a l g r o u p s o f r o c k - f o r m i n g m i n e r a l s a n d h a s s u g g e s t e d a t h e o r e t i c a l m o d e l o f m i n e r a l s t a b i l i t y w i t h r e s p e c t t o f a c t o r s o f r o c k w e a t h e r i n g . A c c o r d i n g t o t h e m o d e l , t h e r e s i s t a n c e o f common r o c k - f o r m i n g m l n e r a l s , s u c h a s q u a r t z , f e l d s p a r a n d mica f o r m a s e r i e s . E x p e r i m e n t a l s t u d i e s o f t h e r e s i s t a n c e o f p r i m a r y a n d c l a y m i n e r a l s h a v e c o n f i r m e d t h e t h e o r e t i - c a l m o d e l ( K o n i s h c h e v e t a l . 1 9 7 4 , 1 9 7 8 ) . I n t h e e x p e r i m e n t s , t h e l e s i s t a n c e o f q u a r t z was l o w e r t h a n t h a t o f n o n - w e a t h e r e d f e l d - s p a r s . T h u s , f o r e x a m p l e , t h e l o w e r p a r t i c l e s i z e l i m i t f o r d i s i n t e g r a t i o n b y f r e e z i n g o f q u a r t z i s f r o m 0 . 0 5 t o 0 . 0 1 mm, a n d t h a t f o r f e l d s p a r from 0 . 1 t o 0 . 0 5 m m . C o n s e q u e n t l y , t h e u l t i m a t e g r a i n s i z e d i s t r i b u t i o n f o r t h e b a s i c r o c k - f o r m i n g m i n e r a l s i n a c o l d a r ea w i t h f r e e z e - t h a w c y c l e s a r e o p p o s i t e t o t h a t o f a w a r m a r e a

w i t h o u t t h e c y c l e s . K o n i s h c h e v e t a l . ( 1 9 7 3 ) h a v e a l s o s h o w n t h a t c e r t a i n m i c r o s t r u c t u r e s o f f i n e g r a i n e d s o i l s c a n f o r m i n r e s p o n s e to r e p e a t e d f r e e z e - t h a w c y c l e s .

W h i t e ( 1 9 7 6 ) h a s r a i s e d t h e q u e s t i o n a s t o w h e t h e r s o m e p r o d u c t s a t t r i b u t e d t o f r o s t a c t i o n may n o t b e t h e r e s u l t o f h y d r a t i o n s h a t t e r i n g w h e r e t h e p r e s s u r e o f a b s o r b e d w a t e r ( h y d r a t i o n ) may g e n e r a t e f o r c e s s u f f i c i e n t t o f r e e g r a i n s a n d d i s i n t e g r a t e r o c k . T h e p r o c e s s , e x p e r i m e n t a l l y s u p - p o r t e d , may b e s i g n i f i c a n t e v e n w i t h o u t f r e e z i n g .

N e w a n d i n t e r e s t i n g d a t a h a v e r e c e n t l y b e e n p u b l i s h e d o n c r y o g e n i c w e a t h e r i n g b e n e a t h g l a c i e r s e S u b g l a c i a l r e g e l a t i o n w e a t h e r i n g w i t h o u t a n y t e m p e r - a t u r e c h a n g e h a s b e e n d i s c u s s e d b y T r o i t s k y e t a l . ( 1 9 7 5 ) a n d M o s k a l e v s k y ( 1 9 7 8 ) . H a l l e t t ( 1 9 7 8 ) h a s d i s c u s s e d c r y o g e n i c c h e m i c a l d e p o s i t s w h i c h can f o r m i n f r e e z i n g s o i l s . The s t u d y o f c r y o g e n i c w e a t h e r i n g a n d r e l a t e d f e a t u r e s c a n s e rve a s a n a i d i n u n d e r s t a n d i n g p r e s e n t p r o c e s s e s a n d t h e i n t e r p r e t a t i o n o f p a l e o c r y o l o g i c c o n d i t i o n s .

CRYOLITHOGENESIS

The term " c r y o l i t h o g e n e s i s " r e f e r s t o t h e g e n e s i s o f p e r m a f r o s t mater- i a l s w i t h s o m e i c e c o n t e n t . T h e w o r d d e r i v a t i o n i s f r o m l i t h o g e n e s i s , t h e o r i g i n a n d f o r m a t i o n o f r a c k s , e s p e c i a l l y s e d i m e n t a r y r o c k s . P o p o v ( 1 9 7 3 , 1 9 7 6 ) u s e s t h e term i n a b r o a d c o n t e x t t o i n c l u d e t h e c o m p l e x i n t e r r e l a t e d g e o l o g i c a n d a s s o c i a t e d p r o c e s s e s i n v o l v e d i n t h e s t u d y o f f r o z e n g r o u n d t h r o u g h s p a c e a n d t ime. By way o f c o n t r a s t , G a s a n o v ( 1 9 7 6 , 1 9 7 8 ) r e s t r i c t s t he term t o s e d i m e n t a r y p r o c e s s e s o f a h y d r o t h e r m a l t y p e . P o p o v , R o z e n b a u m a n d V o s t o k o v a ( 1 9 7 7 , 1 9 7 8 ) h a v e c o m p i l e d a c r y o l i t h o l o g i c a l map o f t h e U . S . S . R . on a s c a l e o f 1 :4,000,000. The c r i t e r i a for t he map l e g e n d a r e b a s e d u p o n a r e c o g n i t f o n o f t h e m a j o r g e n e t i c t y p e s o f p e r m a f r o s t , t h e s p a t i a l a s s o c i a t i o n s o f t h e g e n e t i c t y p e s , a n d t h e p r o c e s s e s b y w h i c h t h e g e n e t i c t y p e s were f o r m e d . The map c l e a r l y shows t h e r e g i o n a l o c c u r r e n c e o f t h e two main g e n e t i c t y p e s o f p e r m a f r o s t , e p i g e n e t i c a n d s y n g e n e t i c . T h e map a l s o s h o w s w h e t h e r t h e f r o z e n g r o u n d i s c o m p o s e d p r i m a r i l y o f i c e ( i . e . a c r y o l i t e s u c h a s t h e i c e c o r e o f a p i n g o o r w e d g e i c e ) o r i s f r o z e n g r o u n d w i t h some i c e ( e g . a c r y o l i t i t e s u c h a s f r o z e n s a n d s or f r o z e n p e a t s ) . T h e map p r o v i d e s a w e a l t h o f i n f o r m a t i o n on c r y o g e n i c t e x t u r e s , t h e e s t i m a t e d a g e o f t he f r o z e n g r o u n d , a n d t h e r e l a t i o n b e t w e e n t h e d i s t r i b u t i o n o f f r o z e n g r o u n d a n d t h e

12

t y p e o f c r y o l i t h o g e n e s i s . T h e c r y o l i t h o - l o g i c a l map i s a n e x c e l l e n t e x a m p l e o f t h e a p p l i c a t i o n o f t h e o r y t o t h e g e n e r a l i - z a t i o n o f e x t e n s i v e g e o c r y o l o g i c d a t a f o r t h e U . S . S . R . V t y u r i n ( 1 9 7 8 ) a d v o c a t e s t h e g e n e t i c a p p r o a c h i n t h e c r y o l i t h o l o g i c a l r e g i o n a l i z a t i o n o f p e r m a f r o s t a r e a s ; i . e . t h e d i s t r i b u t i o n s h o u l d b e m a p p e d , b o t h a r e a l l y a n d a t d e p t h , a c c o r d i n g t o g e n e t i c t y p e s .

I n t h e o p i n i o n o f t h e r e v i e w e r s , t h e s t u d y o f c r y o l i t h o g e n e s i s i n t h e b r o a d s e n s e i s t h e i n t e g r a t i n g f a c t o r i n o u r u n d e r s t a n d i n g o f t h e g e o l o g i c c o n t r o l s o f t h e o r i g i n , c h a r a c t e r i s t i c s , a n d d i s - t r i b u t i o n o f g r o u n d i c e , t h e t h e m e o f t h i s r e v i e w p a p e r .

REFERENCES

AGUIRRE-PUENTE, J . 1 9 7 8 . $ t a t a c t u e l d e s r e c h e r c h e s s u r l e g e l d e s r o c h e s e t d e s m a t d r i a u x d e c o n s t r u c t i o n . P r o c . T h i r d I n t ' l . C o n f . P e r m a f r o s t , V o l . 1. N a t . R e s . C o u n c i l C a n a d a , Ot tawa, p p . 5 9 9 - 6 0 7

0 AHMAN, R . 1 9 7 3 . T h e p i n g o s i n A d v e n t

V a l l e y a n d R e i n V a l l e y , S p i t s b e r g e n . ( I n S w e d i s h ) . S v e n s k G e o g r a f i s k a r s b o k 4 9 , p p . 1 9 0 - 1 9 7 .

Xhman, R . 1 9 7 7 . P a l s a s i n N o r t h e r n N o r w a y . ( I n S w e d i s h ) . T h e R o y a l u n i v e r s i t y o f L u n d , S w e d e n , D e p t . o f G e o g r a p h y P u b l . 7 8 , 1 6 5 p .

A L L E N , C . R . , O ' B R I E N , R . M . G . , a n d SHEPPARD, S .M.P . 1 9 7 6 . T h e c h e m i c a l a n d i s o t o p i c c h a r a c t e r i s t i c s o f s o m e n o r r h e a s t G r e e n l a n d s u r f a c e a n d p i n g o w a t e r s . A r c t i c a n d A l p i n e R e s e a r c h 8 , p p . 297-317 .

ANDERSON, D . M . 1 9 7 7 . G e n e r a l a s p e c t s o f t h e p h y s i c a l s t a t e o f water a n d w a t e r movement i n f r o z e n s a i l s . F r o s t A c t i o n i n S o i l s . I n t ' l . S y m p o s i u m , U n i v e r s i t y of L u l e z , S w e d e n , V o l . 2 , p p . 2 - 1 6 .

ANISOMOVA, N . P . 1 9 7 8 . H y d r o c h e m i c a l i n v e s t i g a t i o n s i n p e r m a f r o s t s t u d i e s . P r o c . T h i r d I n t ' l . P e r m a f r o s t C o n f . V o l . 1. N a t . Res. C o u n c i l C a n a d a , O t t a w a , p p . 4 8 9 - 4 9 4 .

A R E , F . E . 1 9 7 6 . On t h e s u b a q u e o u s c r y o l i t h o z o n e o f t h e A r c t i c O c e a n . In: R e g i o n a l and t h e r m a l - p h y s i c a l s t u d i e s o f f r o z e n r o c k s i n S i b e r i a , Y a k u t s k Book P u b l i s h i n g H o u s e , p p . 3 - 2 7 , Y a k t u s k .

A R E , F . E . 1 9 7 8 . O f f s h o r e p e r m a f r o s t i n t h e A s i a t i c A r c t i c . P r o c . T h i r d I n t ' l . C o n f . P e r m a f r o s t , V o l . 1. Nat. Res. C o u n c i l C a n a d a , O t t a w a , p p . 3 3 5 - 3 4 0 .

B A D U Yu . E . a n d TROFIMOV, V . T . 1 9 7 4 ~ The m a i n r e g u l a r i t i e s o f t h e c r y o g e n i c s t r u c t u r e o f p e r e n n i a l l y f r o z e n r o c k s i n t h e Y a m a l P e n i n s u l a . I n : P r o b l e m s o f C r y o l i t h o l o g y , V o l . I V , p p , 1 2 5 - 1 4 8 , Moscow U n i v e r s i t y P r e s s , M o s c o w .

B A L K W I L L , H . R . , R O Y , K . J . , HOPKINS, W . S . and SLITER, W.V. 1 9 7 4 . G l a c i a l f e a t u r e s a n d p i n g o s , Amund R i n g n e s I s l a n d , A r c t i c A r c h i p e l a g o . C a n . J. E a r t h S c i . 11, p p . 1 3 1 9 - 1 3 2 5 .

BALOBAEV, V . T . 1 9 7 8 , R e c o n s t r u c t i o n o f p a l e o c l i m a t e f r o m p r e s e n t - d a y g e o - t h e r m a l d a t a . P r o c . T h i r d I n t '1. C o n f . P e r m a f r o s t , V o l . 1. N a t . R e s . C o u n c i l C a n a d a , O t t a w a , pp . 10 -1 .4 .

BARSCH, D. 1 9 7 8 . A c t i v e r o c k g l a c i e r s a s i n d i c a t o r s f o r d i s c o n t i n u o u s a l p i n e p e r m a f r o s t . An e x a m p l e f r o m t h e S w i s s A l p s . P r o c . T h i r d T n t ' l . C o n f . P e r m a f r o s t . Na t . Res . C o u n c i l C a n a d a , O t t a w a , p p . 3 4 8 - 3 5 3

B A S T I N , B . , J U V I G N 6 , !$., PISSAXT, A . , a n d T H O R E Z , J . 1 9 7 4 . E t u d e d ' u n e c o u p e d6gagGe a t r a v e r s u n r e m p a r t d ' u n e c i c a t r i c e d e p i n g o d e l a B r a c k v e n n . A n n a l e s d e l a S o c i Z t E G d o l o g i q u e d e B e l g i q u e 9 7 , p p . 341-358 .

B E R D N I K O V , V . V . 1 9 7 6 . T h e p a l e o c r y o g e n i c m i c r o r e l i e f o f t h e c e n t r e o f t h e R u s s i a n P l a i n . N a u k a P u b l i s h i n g H o u s e , Moscow.

BLACK, R . F . 1 9 7 6 . P e r i g l a c i a l f e a t u r e s i n d i c a t i v e o f p e r m a f r o s t : i c e a n d s o i l w e d g e s . Q u a t e r n a r y R e s e a r c h 6 , p p . 3 - 2 6 .

B L A C K , R . F . 1 9 7 8 . F a b r i c s o f i c e w e d g e s i n c e n t r a l A l a s k a . P r o c . T h i r d I n t ' l . C o n f . P e r m a f r o s t . Nat . Res. C o u n c i l C a n a d a , O t t a w a , p p . 2 4 1 - 2 5 3 .

BLETCH, K . E . 1 9 7 4 . On t h e f o r m a t i o n o f p i n g o s i n t h e M a c k e n z i e D e l t a , N . W . T . ( I n G e r m a n ) . P o l a r f o r s c h u n g 4 4 , p p . 6 0 - 6 6 .

BROWN, R . J . E . 1 9 7 4 . G r o u n d i c e a s a n i n i t i a t o r o f l a n d f o r m s i n p e r m a f r o s t r e g i o n s , R e s e a r c h i n P o l a r a n d A l p i n e G e o m o r p h o l o g y (B.D. F a h e y and R . D . T h o m p s o n , E d s . ) . N o r w i c h , E n g l a n d , U n i v e r s i t y o f E a s t A n g l i a , p p . 2 5 - 4 2 .

BROWN., R.J.E. a n d K U P S C H , W . O . 1 9 7 4 . P e r m a f r o s t t e r m i n o l o g y . Na t . R e s . C o u n c i l C a n a d a , Ass. Com. G e o t e c h . Res. , Ottawa, T e c h . Men. No. 111, 6 2 p .

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CLAPPERTON, C . M . 1 9 7 5 . T h e d e b r i s c o n t e n t o f s u r g i n g g l a c i e r s i n S v a l b a r d a n d I c e l a n d . J . G l a c i o l o g y 1 4 , p p . 3 9 5 - 4 0 6 .

c O R T E , A . E . 1 9 7 8 . R o c k g l a c i e r s a s p e r m a - f r o s t b o d i e s w i t h a d e b r i s c o v e r a s a n a c t i v e l a y e r . A h y d r o l o g i c a l a p p r o a c h . A n d e s o f M e n d o e a , A r g e n t i n e . P r o c . T h i r d I n t ' l . C o n f . P e r m a f r o s t , V o l . 1. Na t . Res. C o u n c i l C a n a d a , Ot tawa, p p , 2 6 2 - 2 6 9 .

D A I L Y , B . a n d COOPER, M.R. 1 9 7 6 . C l a s t i c w e d g e s a n d p a t t e r n e d g r o u n d i n t h e L a t e O r d o v i c i a n - E a r l y S i l u r i a n t i l l i t e s o f S o u t h A f r i c a . S e d i m e n t o l o g y 2 3 , p p . 2 7 1 - 2 8 3 .

DOSTOVALOV, B . H . 1 9 5 2 . A b o u t t h e p h y s i c a l c o n d i t i o n s o f f o r m a t i o n o f f r o s t - c a u s e d f i s s u r e s a n d d e v e l o p m e n t o f f i s s u r e i c e i n u n c o n s o l i d a t e d r o c k s . I n : S t u d i e s o f P e r m a f r o s t i n t h e Y a k u t i a n R e p u b l i c , V o l . 3 , p p , 1 6 2 - 1 9 4 , A c a d e m y o f S c i e n c e s o f t h e U . S . S . R . P u b l i s h i n g H o u s e , Moscow.

ERSHOV, E . D . 1 9 7 7 . T h e m e c h a n i s m o f m i g r a t i o n - s e g r e g a t i o n a l i c e e x p u l s i o n i n f r e e z i n g a n d t h a w i n g d i s p e r s e d g r o u n d s . H e r a l d o f Moscow U n i v e r s i t y , S e r i e s o f G e o l o g y , N o . 3 , p p . 9 7 - 1 0 8 . Moscow.

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EVSEEV, V . P . 1 9 7 6 . M i g r a t i o n a l h u m m o c k s o f h e a v i n g i n t h e n o r t h e a s t o f t h e E u r o p e a n p a r t o f t h e U . S . S . R . a n d W e s t e r n S i b e r i a . I n : P r o b l e m s o f c r y o l i r h o l o g y , V o l . V , Moscow.

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FOTIEV, S .M., D A N I L O V A , N . S . , a n d SHEVELEVA, N . S . 1 9 7 4 . The g e o c r y o l o g i - c a l c o n d i t i o n s o f C e n t r a l S i b e r i a . I n s t . o f G e o c r y o l o g y , S i b e r i a n B r a n c h , Academy o f S c i . o f t h e U . S . S . R . , Moscow.

FRENCH, H . M . 1 9 7 4 . A c t i v e T h e r m o k a r s t p r o c e s s e s , e a s t e r n B a n k s I s l a n d , W e s t e r n C a n a d i a n A r c t i c , Can . J . E a r t h S c i . 11, p p . 7 8 5 - 7 9 4 .

FUJTT, Y . a n d H I G U C H I , K . 1 9 7 8 . Dis t r i - b u t i o n o f a l p i n e p e r m a f r o s t i n t h e n o r t h e r n h e m i s p h e r e a n d i t s r e l a t i o n t o a i r t e m p e r a t u r e . P r o c . T h i r d I n t ' l . C o n f . P e r m a f r o s t , V o l . I. Na t . Res, C o u n c i l C a n a d a , O t t a w a , p p . 3 6 6 - 3 7 1 .

FYODOROV, I.S. a n d I V A N O V , N . S . 1 9 7 4 . E n g l i s h - R u s s i a n g e o c r y o l o g i c a l d i c t i o n - a r y . Y a k u t s k S t a t e U n i v e r s i t y , Y a k u t s k , U . S . S , R . , 1 2 6 p .

GASANOV, S.S. 1 9 7 6 . E x t r e m e r e c u r r e n t - v e i n i c e . I n : S e a s o n a l l y a n d P e r e n - n i a l l y f r o z e n r o c k s , p p . 3 1 - 4 1 . V l a d i v o s t o k .

GASANOV, S . S . 1 9 7 7 . S u b l i m a t i o n a l r e d i s - t r i b u t i o n o f m a t t e r s i n r e c u r r e n t - v e i n i c e . I n : P r o b l e m s o f C r y o l i t h o - l o g y , V o l . VI, p p . 2 2 4 - 2 2 9 , M O S C O W U n i v e r s i t y P r e s s , Moscow.

G A S A N O V , S h . S h . 1 9 7 8 . C r y o l i t h o g e n e s i s a s a n i n d e p e n d e n t h y d r o t h e r m a l t y p e o f s e d i m e n t a r y p r o c e s s . P r o c . T h i r d I n t ' l . C o n f . P e r m a f r o s t , V o l . 1. Na t . Res . C o u n c i l C a n a d a , O t t a w a , p p . 2 7 0 - 2 7 6 .

G A T T O , L.W. a n d ANDERSON, D . M . 1 9 7 5 . A l a s k a n t h e r m o k a r s t r e r r a i n a n d p o s s i b l e M a r t i a n a n a l o g . S c i e n c e 1 8 8 , p p . 2 5 5 - 2 5 7 .

G E L L , W . A . 1 9 7 8 . T h e r m a l c o n t r a c t i o n c r a c k s i n m a s s i v e s e g r e g a t e d i c e , T u k t o y a k t u k P e n i n s u l a , N . W . T . , C a n a d a . P r o c , T h i r d I n t ' l . C o n f . P e r m a f r o s t , V o l . 1. N a t . R e s . C o u n c i l C a n a d a , O t t a w a , p p . 2 7 7 - 2 8 1 .

GOLDSHTEIN, M,N. 1 9 5 2 . M e c h a n i c a l p r o p e r - t i e s o f g r o u n d s . G o s s t r o i i z d a t ( S t a t e B u i l d i n g P u b l i s h e r s ) , M o s c o w .

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G O R B U N O V , A . P . 1 9 7 6 . T h e c r y o s p h e r e o f t h e E a r t h ' s c r u s t i n t h e m o u n t a i n o u s r e g i o n s . I n : P r o b l e m s o f t h e C r y o l o g y o f t h e E a r t h , p p . 3 8 - 4 8 , N a u k a P u b l i s h - i n g H o u s e , M o s c o w .

G O R B U N O V , A . P . 1 9 7 8 . P e r m a f r o s t i n t h e m o u n t a i n s o f C e n t r a l A s i a . P r o c . T h i r d I n t ' l . C o n f . P e r m a f r o s t , v o l . 1. Na t . Res. C o u n c i l C a n a d a , O t t awa , p p . 3 7 2 - 3 7 7 .

GRAVIS, G.F. 1 9 7 4 . T h e c r y o g e n l c s t r u c - t u r e o f p e r e n n i a l l y f r o z e n r o c k s . I n : T h e g e o c r y o l o g i c a l c o n d i t i o n s I n t h e M o n g o l i a n P e o p l e ' s R e p u b l i c . N a u k a P u b l . H o u s e , M o s c o w .

GRAVIS, G . F . , POPOV, A . I . a n d T O L S T I K H I N , N.T. 1 9 7 4 . U n d e r g r o u n d i c e , c r y o g e n i c s t r u c t u r e a n d c r y o g e n i c - f a c i e s a n a l y s i s o f f r o z e n r o c k s . C h a p t e r VII. I n : G e n e r a l G e o c r y o l o g y , p p . 1 3 5 - 1 6 0 , N a u k a P u b l i s h i n g H o u s e , S i b e r i a n b r a n c h , N o v o s i b i r s k .

GRAVIS, G . P . 1 9 7 8 . C y c l i c n a t u r e o f t h e r m o k a r s t o n t h e Mari t ime P l a i n i n t h e u p p e r P l e i s t o c e n e a n d H o l o c e n e . P r o c . T h i r d T n t ' l . C o n f . P e r m a f r o s t , V o l . 1. Nat . R e s . C o u n c i l C a n a d a , O t t a w a , pp . 282-287 .

G R E C H I S H C H E V , S . E . 1 9 7 5 . An a p p r o a c h t o t h e e s t i m a t i o n o f c r y o g e n i c f i s s u r e d e p t h s a n d o f s i z e s o f t h e p o l y g o n s o f c r a c k i n g i n s o i l s . I n : G e o c r y o l o - g i c a l i n v e s t i g a t i o n s . P r o c . V S E G I N G E O , V O l . 8 7 , Moscow.

G R E C H I S H C H E V , S.E. 1 9 7 6 . Some p r o b l e m s o f t h e t h e r m o r h e o l o g y o f f r o z e n g r o u n d . In: P r o b l e m s o f t h e C r y o l o g y o f t h e E a r t h , N a u k a P u b l i s h i n g H o u s e , M o s c o w .

GRECHISHCHEV, S . E . 1 9 7 8 . Some a s p e c t s o f t h e m e c h a n i c s o f f r o s t f r a c t u r i n g o f s o i l s i n t h e p e r m a f r o s t z o n e . P r o c , T h i r d I n t ' l . C o n f . P e r m a f r o s t , V o l . 1. N a t . Res. C o u n c i l C a n a d a . O t t a w a , p p . 2 8 8 - 2 9 4 .

G U Y M O N , E . L . a n d L U T H I N , J . N . 1 9 7 4 . a c o u p l e d h e a t and m o i s t u r e t r a n s p o r t m o d e l f o r a r c t i c s o i l s . Water R e s o u r c e s Res. 1 0 , p p , 9 9 5 - 1 0 0 1 .

H A E B E R L I , W . 1 9 7 8 . S p e c i a l a s p e c t s o f h i g h m o u n t a i n p e r m a f r o s t m e t h o d o l o g y a n d z o n a t i o n i n t h e A l p s . P r o c . T h i r d I n t ' l . Conf. P e r m a f r o s t , V o l . 1. Nat. Res. C o u n c i l C a n a d a , O t t a w a , p p . 3 7 8 - 3 8 4 ,

H A L L E T , B . 1 9 7 8 . S o l u t e r e d i s t r i b u t i o n i n f r e e z i n g g r o u n d . P r o c . T h i r d I n t ' l . Conf . P e r m a f r o s t , V o l . 1 e Nat . Res. c o u n c i l C a n a d a , O t t a w a , p p . 8 5 - 9 1 .

H A R R I S , S . A . a n d BROWN, R . J . E . 1 9 7 8 . P l a t e a u M o u n t a i n : A c a s e s t u d y o f a l p i n e p e r m a f r o s t i n t h e C a n a d i a n R o c k y M o u n t a i n s . P r o c . T h i r d I n t ' l . C o n f . P e r m a f r o s t , VoL. 1. Nat . R e s , C o u n c i l C a n a d a , O t t awa , p p . 3 8 5 - 3 9 1 .

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HILL, D. a n d MORGFNSTERN, N . R . 1 9 7 7 . I n f l u e n c e o f l o a d a n d h e a t e x t r a c t i o n o n m o i s t u r e t r a n s f e r i n f r e e z i n g s o i l s . F r o s t A c t i o n i n S o i l s . I n t ' l . Sympos- i u m , U n i v e r s i t y o f L u l e 8 , S w e d e n , V o l . 1, p p . 7 6 - 9 1 .

H U N T E R , J . A . , N E A V E , K . G . , MAC AUEAY, H , A . , a n d HOBSON, G.D. 1 9 7 8 . I n t e r p r e - t a t i o n o f s u b - s e a b o t t o m p e r m a f r o s t i n t h e B e a u f o r t S e a b y s e i smic m e t h o d s . P a r t 1 S e i s m i c - r e f r a c t i o n m e t h o d s . P r o c . T h i r d I n t ' l . C o n f . P e r m a f r o s t , V o l . 1. Na t . Res. C o u n c i l C a n a d a , O t t a w a , p p . 5 1 4 - 5 2 0 .

ISKANDAR, I . K . , OSTERKAMP, T . E . a n d HARRISON, W . D . 1 9 7 8 . C h e m i s t r y o f i n t e r s t i t i a l water f r o m s u b s e a p e r m a - f r o s t , V o l . 1. Nat . Res. C o u n c i l C a n a d a , O t t a w a , p p . 9 2 - 9 8 .

J A H N , A . 1 9 7 5 . P r o b l e m s o f t h e P e r i - g l a c i a l Z o n e . ( T r a n s . f r o m P o l i s h ) . U . S . D e p t . C o m m e r c e , N a t i o n a l T e c h n i - c a l I n f o r m a t i o n S e r v i c e , S p r i n g f i e l d , V a . T T 7 2 - 5 4 0 1 1 , 2 2 3 p .

J A H N , A . 1 9 7 6 . P a l s a - t y p e f r o s t m o u n d s . ( I n P o l i s h ) . S t u d i a S o c i e t a t i s S c i e n t i a r u m T o r u n e n s i s , G e o g r a p h i a e t G e o l o g i a , V o l . 8 , S e c t i o n C , p p . 1 2 3 - 1 3 9 .

JUMIKIS, A . R . 1 9 7 7 . The c r y o g e n i c s y s t e m s o i l - w a t e r - t e m p e r a t u r e . F r o s t A c t i o n i n Soils. I n t ' l . S y m p o s i u m , U n i v e r s i t y o f L u l e 8 , S w e d e n , V o l . 1, p p . 1 1 2 - 1 2 0 .

KAPLINA, T . N . 1 9 7 6 . T h e s p e c i a l f e a t u r e s o f m o d e r n d e v e l o p m e n t of p o l y g o n a l - w e d g e i c e i n t h e K o l y m a l o w l a n d . I n : P r o b l e m s o f C r y o l i t h o l o g y , V o l . V , p p . 7 9 - 8 6 , M o s c o w U n i v e r s i t y P r e s s , Moscow.

KAPLXNA, T . N . a n d KUZNETSOVA, I . L . 1 9 7 5 . T h e g e o - t e m p e r a t u r e a n d c l i m a t i c m o d e l o f t h e e p o c h o f s e d i m e n t a t i o n o f t h e edoma s u i t e i n t h e P r i m o r s k a y a l o w l a n d o f Y a k u t i a . I n : P r o b l e m s o f t h e r e g i o n a l a n d t h e g e n e r a l p a l e o g e o g r a p h y o f l o e s s i a l a n d p e r i g l a c i a l a r e a s . N a u k a P u b l i s h i n g H o u s e , M o s c o w .

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KAPLYANASKAYA, F .A . and TARNOGRADSKY, V . D . 1 9 7 6 . R e l i c t g l a c i e r I c e in t h e n o r t h o f W e s t e r n S i b e r i a a n d i t s r o l e I n t h e s t r u c t u r e o f r e g i o n s o f t h e P l e i s t o c e n e g l a c i a t i o n o f t h e c r p o l i t h o z o n e , F a r - E a s t e r n S e c t i o n o f t h e A c a d . o f S c i . o f t h e U . S . S . R . , V o l . 2 3 1 , No. 5 . V l a d i v o s t o k .

K A T A S O N O V , E .M. 1 9 7 5 . T h e p r e s e n t c r y o - g e n i c f o r m a t i o n s a n d t h e i r r e l a t i o n t o t h e g e n e s i s o f t h e e n c l o s i n g d e p o s t s . I n : R e g i o n a l a n d t h e m a t i c g e o c r y o l o g l c a l i n v e s t i g a t i o n s , N a u k a P u b l i s h i n g H o u s e , N o v o s i b i r s k .

KONISHCHEV, V . N . 1 9 7 4 . T h e a g e o f u n d e r - g r o u n d i c e i n t h e Y a n a - I n d i g i r k a l o w l a n d . I n : P r o b l e m s o f C r y o l i t h o l o g y , V o l . I V , p p . 1 1 0 - 1 1 4 , M o s c o w U n i v e r s i t y P r e s s . Moscow,

KONISHCHEV, V . N . 1 9 7 7 . G e n e r a l r e g u l a r - i t i e s o f t h e c r y o g e n i c d e s i n t e g r a t i o n o f m i n e r a l s . I n : F r o z e n r o c k s a n d t h e s n o w c o v e r , p p . 3 - 1 6 , N a u k a P u b l i s h i n g House , Moscow.

K O N I S H C H E V , V . N . 1 9 7 8 . M i n e r a l s t a b i l i t y i n t h e z o n e o f c r y o l l t h o g e n e s i s . P r o c . T h i r d I n t ' l . C o n f . P e r m a f r o s t , V o l . 1. Na t . Res. C o u n c i l C a n a d a , O t t awa , p p . 305-311 .

KONISHCHEV, V . N . , FAUSTOVA, M . A . , a n d R O G O V , V . V . 1 9 7 3 . C r y o g e n i c p r o c e s s e s as r e f l e c t e d i n g r o u n d m i c r o s t r u c t u r e . P e r i g l a c i a l B u l l . 2 2 , p p . 2 1 3 - 2 1 9 .

KONXSHCHEV, V . N . , R O G O V , V . V . a n d SHCHURIN, G . N . 1 9 7 4 . T h e i n f l u e n c e o f c r y o g e n i c f a c t o r s on c l a y m i n e r a l s . H e r a l d o f Moscow U n i v e r s i t y , S e r i e s o f G e o g r a p h y , No. 4 , Moscow U n i v e r s i t y P r e s s , M o s c o w .

KONISHCHEV, V . N . a n d R O G O V , V . V . 1 9 7 8 . An e x p e r i m e n t a l m o d e l o f t h e c r y o g e n i c r e s i s t a n c e o f b a s i c r o c k - f o r m i n g m i n e r - a l s . I n : P r o b l e m s o f C r y o l i t h o l o g y , V o l . V I I , Moscow U n i v e r s i t y P r e s s , Moscow.

KOREISHA, W,M. 1 9 7 6 . Some p r o b l e m s o f t h e s t u d i e s o f s u b a e r i a l a n d s u b t e r r - a n e a n i c e o f t h e n o r t h e a s t o f t h e U . S . S . R . I n : P r o b l e m s o f t h e C r y o l o g y o f t h e E a r t h , p p . 1 7 0 - 1 7 3 , N a u k a P u b l i s h i n g H o u s e , M o s c o w .

KOWALKOWSKI, A . 1 9 7 8 . T h e c a t e n a o f p e r m a f r o s t soils i n t h e B a y a n - N u u r i n - K h o t n o r B a s i n , K h a n g a i Mts., M o n g o l i a . P r o c . T h i r d I n t ' l . P e r m a f r o s t C o n f . , V o l . 1 . Nat. Res. C o u n c i l C a n a d a , Ottawa, p p . 413-418 .

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K V L I V I D Z E , V , I . , KISELEV, V.F., K R A S N U S H K I N , A . V . , K U R Z A E V , A . B . a n d U S H A K O V A , L . A . 1 9 7 8 . An NMB s t u d y o f t h e p h a s e t r a n s i t i o n o f water i n m o d e l s a n d i n f r o z e n c l a y s . P r o c . T h i r d I n t ' L . C o n f . P e r m a f r o s t , V o l . 1. Na t . Res. C o u n c i l C a n a d a , O t t a w a , p p . 1 1 3 - 1 1 8 .

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TAKASHI, T . , YAMAMOTQ, H . , O H R A I , T . , a n d MASUDA, M . 1 9 7 8 . E f f e c t o f p e n e - t r a t i o n r a t e o f f r e e z i n g a n d c o n f i n i n g s t r e s s on t h e f r o s t h e a v e r a t i o o f s o i l . P r o c . T h i r d I n t ' l . C o n f . Perrna- f r o s t , V o l . 1. Nat . Res. C o u n c i l C a n a d a , O t t a w a , p p . 736-742 .

T H I B O D E A U , E . a n d CAILLEUX, A . 1 9 7 3 . Z o n a t i o n e n l a t i t u d e d e s t r u c t u r e s d e t h e r m o k a r s t e t d e t o u r b i ' s r e s v e r s 700 o u e s t , QuEbec . Rev . GEogr . M o n t r . 2 7 , p p . 1 1 7 - 1 3 8 .

T P C E , A .B . , BURROUS, C . M . a n d ANDERSON, D . M , 1 9 7 8 , D e t e r m i n a t i o n o f u n f r o z e n w a t e r i n f r o z e n s o i l b y p u l s e d n u c l e a r m a g n e t i c r e s o n a n c e . P r o c . T h i r d I n t ' l . C o n f . P e r m a f r o s t , V o l . 1 . N a t . R e s . C o u n c i l C a n a d a , O t t a w a , p p . 1 4 9 - 1 5 5 .

T O M I R D I A R O , S . V . , BEBCHUN, V , K . a n d T R A V I N , Yu. A . 1 9 7 5 , M a n t l e o c c u r r - e n c e s o f t h e U p p e r P l e i s t o c e n e l o e s s - i c e c o m p l e x e s i n t h e n o r t h e a s t o f As ia a s a n i n d i c a t o r o f t h e i r a e o l i a n - c r y o - g e n i c o r i g i n , K o l y m a , N o . 4 .

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U G O L I N I , F . C . 1 9 7 5 . I c e - r a f t e d s e d i m e n t s a s a c a u s e o f s o m e t h e r m o k a r s t l a k e s i n t h e Noa t a k R i v e r D e l t a , A l a s k a . S c i e n c e 1 8 8 , p p , 5 1 - 5 3 .

V A N E V E R D I N G E N , R , O . 1 Y 7 6 . G e o c r y o l o g i - c a l t e r m i n o l o g y . C a n . J , E a r t h S c i . 1 3 , p p . 8 6 2 - 8 6 7 .

V A N E V E R D I N G E N , R . O . 1 9 7 8 . F r o s t m o u n d s a t B e a r R o c k , n e a r F o r t N o r m a n , N o r t h - wes t T e r r i t o r i e s , 1 9 7 5 - 1 9 7 6 . C a n . J . E a r t h S c i . 1 5 , p p . 2 6 3 - 2 7 6 .

18

VELTKOTSKY, M . A . 1 9 7 4 . A b o u t t h e r o l e o f t e c t o n i c j o i n t i n g i n t h e d e v e l o p m e n t o f r h e r m o k a r s t i n t h e n o r t h o f t h e Y a n a - O m o l o i i n t e r f l u v e . I n : P r o b l e m s o f C r y o l i t h o l o g y , V o l . IV, p p . 244-251 , Moscow U n i v e r s i t y P r e s s , M o s c o w .

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VTYURIN, B . T . 1 9 7 5 . U n d e r g r o u n d i c e i n t h e U . S . S . R . N a u k a P u b l i s h i n g H o u s e , Moscow.

V T Y U R I N , B . K . 1 9 7 8 . P r i n c i p l e s o f c r y o - l i t h o l o g i c a l r e g i o n a l i z a t i o n o f t h e p e r m a f r o s t z o n e . P r o c . T h i r d I n t ' l . C o n f . P e r m a f r o s t , V o l . 1. Na t . Res . C o u n c i l C a n a d a , Otrawa, p p . 4 4 5 - 4 4 9 .

VTYUBINA, E . A . 1 9 7 4 . T h e c r y o g e n i c s t r u c t u r e o f r o c k s i n a s e a s o n a l l y t h a w i n g l a y e r . N a u k a P u b l . H o u s e , Moscow.

WASHBURN, A . L . G e o c r y o l o g y : A S u r v e y o f P e r i g l a c i a l P r o c e s s e s a n d m e n t s . L o n d o n , E d w a r d A r n o l d

E n v i r o n - ( i n p r e s s ) .

WATSON, E . 1 9 7 7 . T h e p e r i g l a c m e n t o f G r e a t B r i t a i n d u r i n g D e v e n s i a n , P h i l . T r a n s . Roy B 2 8 0 , p p . 1 8 3 - 1 9 8 .

W H I T E . S.E. 1 9 7 6 . Is f r o s t a c

i a 1 e n v i r o n - t h e

S o t . L o n d .

i o n r e a l l y t o n l y h y d r a t i o n s h a t t e r i n g ? A r e v i e w . A r c t i c a n d A l p i n e Res . 8 , p p . 1 - 6 .

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WILLIAMS, P . J . 1 9 7 7 . T h e r m o d y n a m i c c o n - d i t i o n s f o r i c e a c c u m u l a t i o n i n f r e e z i n g s o i l s . F r o s t A c r i o n i n S o i l s . I n t ' l . S y m p o s i u m , U n i v e r s i t y o f L u l e g , S w e d e n , p p . 4 2 - 5 3 .

W O O D C O C K , A . H . 1 9 7 4 . P e r m a f r o s t a n d c l i m a t o l o g y o f a H a w a i i v o l c a n o c r a t e r . A r c t i c a n d A l p i n e Res. 6 , p p . 4 9 - 6 2 .

Y O U N G , G . M . a n d L O N G , D . G . F . 1 9 7 6 . I c e - w e d g e c a s t s f r o m t h e H u r o n i a n R a m s a y L a k e . F o r m a t i o n ( > 2 , 3 0 0 m . y . o l d ) n e a r E s p a n o l a , O n r a r i o , C a n a d a . P a l a e o g e o - g r a p h y , P a l a e o c l i m a t o l o g y , P a l a e o e - cology 1 9 , p p . 191-,2OO.

Z H E S T K O V A , T . N . a n d GUZHOV, V . G . , 1 9 7 6 . Some e x p e r i m e n t a l d a t a o n t h e d y n a m i c s o f c r y o g e n i c t e x t u r e s i n a f r e e z i n g g r o u n d . I n : C r y o g e n i c S t u d i e s , V o l . 1 5 , p p . 2 1 5 - 2 2 5 , Moscow U n i v e r s i t y P r e s s . Moscow.

ZHESTKOVA, T . N . 1 9 7 8 , R e s u l t s o f e x p e r i m e n t a l s t u d i e s o f t h e f r e e z i n g p r o c e s s i n v e r y f i n e - g r a i n e d soils. P r o c . T h i r d I n t ' l . C o n f . P e r m a f r o s t , Vol. 1. Nat. Res. C o u n c i l C a n a d a , O t t a w a , p p . 1 5 6 - 1 6 2 .

Z H I G A R E V , L . A . a n d PLAKHT, I . R . 1 9 7 4 . C h a r a c t e r i s t i c s o f t h e s t r u c t u r e , d i s t r i b u t i o n a n d f o r m a t i o n o f t h e s u b a q u e o u s c r y o g e n i c r o c k s e r i e s . I n : P r o b l e m s o f C r y o l i t h o l o g y , V o l . I V , p p . 1 1 5 - 1 2 4 , M o s c o w U n i v e r s i t y P r e s s , Moscow.

19

MEP3J'IOTHO-~A~POPEO~O~HW3CKOE PAfiOHHPOBAHME BOCTO~HOR cumm

n.M.MenbHnKOB HM CO AH CCCP

0 .H .ToncTnxuH - BCEMHI'EO

20

1. ~ O C T O V H O - C H 6 n p C K a R apTe3naHCKaR 06- naCTb no reonoruvecKnM y c n o s u x ~ npencTasnR-

21

23

25

26

27

28

4. KaWaTCKO-KOpaKCKaK rnnporeonorwecxau cKnansaTaR obnac~b npocrapaeTcH H a TeppnTo' pum BOCTOYHOR Cu6upu c~oeR CeBepHoR, KOPFIK

29

30

11. COJIOBbeBa n.H. MopQonorna KpHOJ'IHT030Hhf Camo-BaftKanbcKaB oBnacTn. H O B O C H ~ H P C K , HJA-BO "HayKa" , CnBnpcxoe oTneneHHe, 1 9 7 6 , 126 c . 1 2 . A@aHaceHxo B.E., HaftMapK A.A. Hanenoob- pa30BaHNe H HeOTeKTOHWKa MOMCKQft PU@TOBOi3 06JIaCTU (CeBepO-BOCTOK CCcP). COBeTCKaFl reo-

1 3 . AQaHaCeHKO B.E.# MopKoBKNna H.K. 0 B03-

CeneHHSIXCKOR HaJlOJKRteHHOft BlIaAHHH. "BBCTHHK

norm, 1 9 7 7 , H 4 , c.66-77.

pame nome~~rdx 8on xpe6~a Tac-XaRxTax a

MrY, cep.reon.", 1 9 7 3 , N 5 , c.105-109. 1 4 . ranporeonoran CCCP, T . XXVI, Cesepo- BOCTOK CCCP.M., u3n-BO "Henpa", 1972, 2 9 5 c.

31

VEGETATION AND REEGETATIO!I WITHIN PEWROST TERRAIPI

L . C . Bl iss, Depar tment o f Botany

U n i v e r s i t y o f A1 be r ta , Edmonton*

INTRODUCTION

Permafrost , both cont inuous and d iscont inuous, cove rs vas t a reas w i th in c i r cumpo la r l ands . All o f t h e a r c t i c t u n d r a , p o l a r s e m i - d e s e r t s and p o l a r deser ts a re under la in by con t inuous permaf ros t (F ig . 1 ) . To t h e s o u t h , t h e f o r e s t - t u n d r a t r a n s i t i o n and t h e n o r t h e r n p o r t i o n o f t h e open f o r e s t , g e n e r a l l y a spruce- l ichen woodland i n N o r t h America and a l a rch - l i chen wood land i n S ibe r ia , occu r on con t inu - ous permaf ros t . The n o r t h e r n p o r t i o n o f t h e t a i g a o r c l o s e d b o r e a l f o r e s t i s a l s o u n d e r l a i n b y c o n - t inuous permaf ros t . Much o f t h e r e m a i n i n g t a i g a i s f ound on d i scon t inuous pe rmaf ros t , espec ia l l y i n up lands and poor ly dra ined areas.

The r e l a t i o n s h i p o f v e g e t a t i o n t o p e r m a f r o s t on a macro-sca le and p lan t communi t ies to depth o f the a c t i v e l a y e r on a mic ro-sca le , has been of i n t e r e s t t o e c o l o g i s t s f o r a number o f y e a r s . S t u d i e s o f v e g e t a t i o n i n r e l a t i o n t o p e r m a f r o s t and t e r r a i n have taken on a new meaning w i th t he i nc reased pace of northern development.

The o b j e c t i v e o f t h i s p a p e r i s t o d e s c r i b e t h e v e g e t a t i o n p a t t e r n s w i t h i n t h e t a i g a , Low, and H igh A r c t i c as t h e y r e l a t e t o t o p o g r a p h y and dra inage as i n f l uenced by pe rmaf ros t and depth o f t h e a c t i v e 1 ayer +

The r o l e o f s p e c i e s u s e f u l i n r e h a b i l i t a t i n g s u r f a c e d i s t u r b e d n o r t h e r n l a n d s will also be d i s - cussed i n r e l a t i o n t o northern development.

VEGETATION OF SUBARCTIC AND ARCTIC LANDS TAIGA

I n t r o d u c t i o n

The t a i g a or borea l fo res t covers an es t imated 9.9 x 106 km2 c i rcumpolar . O f t h i s t o t a l , 2.5-3.0 x 106 km2 compr i se t he f o res t - tund ra and open boreal woodland (Weck and Wiebecke 1961). Here, as i n t h e A r c t i c , t h e f o r e s t l a n d s a r e s u b d i v i d e d i n t o zones (Tab le 1 ) . As will be d iscussed be low, th is i s l a r g e l y based upon t r e e d e n s i t y , p l a n t g r o w t h form o r physiognomy, and species present. The t a i g a has been c l a s s i f i e d i n v a r i o u s ways, r e s u l t - i n g i n c o n f u s i o n f o r e c o l o g i s t s , l e t a l o n e e n g i n e e r s un less the te rms a re c lea r l y de f i ned . Zona t ion systems o f c l a s s i f i c a t i o n were discussed by

Bl i i thgen (1970) , Hust ich (1970) , and Tikhomirov (1970) a t t h e symposium on "Eco logy o f t he Sub- a r c t i c Regions" i n H e l s i n k i . The c l a s s i f i c a t i o n used here fo l lows Hare and Ri tchie (1972). The f o r e s t - t u n d r a ( l e s o t u n d r a ) c o n s i s t s o f i s o l a t e d o r smal 1 clumps o f de fo rmed t rees se t i n a tundra landscape, genera l l y shrub tundra o r co t tongrass- heath tundra. These areas grade into open wood- l a n d i n w h i c h s c a t t e r e d u p r i q h t t r e e s o c c u r w i t h a ground cover o f l i chens o r sh rubs . The l i c h e n woodlands o f O n t a r i o , Quebec, and Newfoundland typi fy these communit ies (Hare 1951, Hust ich 1951, A h t i 1951, Rouse and Kershaw 1971, Kershaw 1978). TO t h e s o u t h t r e e d e n s i t y i n c r e a s e s u n t i l c l o s e d bo rea l f o res t i s encoun te red . T ree l i ne occu rs a t t h e n o r t h e r n edge of f o r e s t - t u n d r a and f o r e s t l i n e a t t h e n o r t h e r n edqe o f t h e c l o s e d f o r e s t . An anno ta ted b ib l i og raphy on t h e r e l a t i o n s h i p o f v e g e t a t i o n , w i l d l i f e , and land fo rm to pe rmaf ros t c o v e r s t h e e a r l i e r 1 i t e r a t u r e ( R o b e r t s - P i c h e t t e 1972).

C1 osed Forest

The c l o s e d b o r e a l f o r e s t c o n t a i n s r e l a t i v e l y f e w p l a n t and an imal spec ies, s ing le t ree spec ies o f ten dominat ing the landscape for many square k i l omete rs . The f o r e s t s , u s u a l l y o f c o n i f e r s , o f ten have an u n d e r s t o r y o f f e a t h e r mosses and a few sca t te red he rbs and low shrubs. The f o r e s t e d p a t t e r n i s b r o k e n i n p o o r l y d r a i n e d l a n d s w h e r e fens and bogs are common (Hus t i ch 1957, R i t c h i e 1959, S j i j r s 1959, 1965a, Osvald 1970, Vitt and Slack 1975). Fig. 2 dep ic ts the genera l vegeta- t i o n p a t t e r n i n r e l a t i o n t o t o p o g r a p h y , s o i l s and depth o f t h e a c t i v e l a y e r n e a r Sans Sau l t Rap ids , NWT.

Most o f t h e c l o s e d f o r e s t l i e s s o u t h o f d i s - con t inuous permaf ros t . Wi th in the d iscont inuous zone o f p e r m a f r o s t i n Canada, f o r e s t s o f Picea mariunu predominate. Th is spec ies is most common i n p o o r l y d r a i n e d l a n d s , b u t t o t h e n o r t h and west, b l a c k s p r u c e i s f o u n d i n u p l a n d s as w e l l . PCcea gZuuca i s more common on warmer and more deep ly thawed s o i l s , t h o u p h w h i t e s p r u c e i s f o u n d a t h ighe r e leva t i ons t han b lack sp ruce i n A laska ( B r i t t o n 1957) and the Yukon, f u r t h e r n o r t h a l o n g a r c t i c f l o w i n g r i v e r s (Drew and Shanks 1965, H e t t i n g e r e t a l . 1973, H e t t i n g e r and Janz 1974), and i n more ex t reme mar i t ime cond i t i ons i n t he Hudson Bay Lowland (R i tch ie 1957, Hust ich 1957) .

32

Table 1. Genera l c lass i f i ca t i on o f Ta iga , Tundra , and Po la r Deser t

Nor th Amer ica (B l i ss 1979) USSR (A1 eksandrova 1970)

Ta iga c losed fo res t Taiga woodland Forest-Tundra

Low A r c t i c Tundra

t a l l , low, sub shrub, Hummocky (cot tongrass)-sub shrub, wet sedge-moss

H i g h A r c t i c Tundra

wet sedge-moss ( m i r o r )

Polar semi-deser t cushion plant, moss-herb, l i chen -he rb

Polar Deser t herb (few cryptogams)

Trees o f l e s s e r i m p o r t a n c e i n c l u d e Abies bulsmerx i n e a s t e r n and cent ra l Canad ian fo res ts , Pinus banksiana i n sandy s o i l s and d ry rocky so i l s wes t t o t he Grea t Bear Lake reg ion and Laria: %ari.cina scat te red th roughout . The l a t t e r s p e c i e s r e a c h e s i t s maximum importance i n t h e Hudson Bay Lowland where it forms pure stands i n p o o r l y d r a i n e d s o i l s (Hus t i ch 1957, Rowe 1972).

The dec iduous t ree spec ies Pc~puZus trerrmZoides, P. ba l smi f e ra , and Betula p a p y r i f w a comprise a r e l a t i v e l y m i n o r p o r t i o n o f these nor thern borea l f o res ts . These species grow best where the act ive l a y e r i s r e l a t i v e l y deep and t h e s o i l s a r e b o t h warmer and b e t t e r d r a i n e d t h a n i n n e a r b y s i t e s w i t h Picea mariann. (Rowe 1972).

I n A laska, V ie reck (1975) has c lass i f ied ta iga vegetat ion a long temperature and mois ture gradients . Here, Piem gZuuca r a t h e r t h a n P. mnarinm d e l i n e a t e s t h e t a i g a . The l a t t e r s p e c i e s i s g e n e r a l l y f o u n d i n p o o r l y d r a i n e d s o i l s w i t h a s h a l l o w a c t i v e l a y e r . Lapix Zaricina i s more l i m i t e d i n i t s d i s t r i b u t i o n and importance as a fo res t spec ies . I t i s r a r e i n t h e r e l a t i v e l y warm Yukon R i v e r V a l l e y ( V i e r e c k 1975). As i n Canada, Populus tremu2nide.s i s found i n areas o f h igher degree-day accumulat ion. Pinus and Abies a r e n o t p a r t of t hese no r the rn f o res ts .

Only d iscont inuous permafrost extends across northern Fennoscandia, mainly i n t h e m o u n t a i n s . The c l o s e d f o r e s t c o n s i s t s m o s t l y of P i e m exceZLsa w i t h open stands o f ~ i n u v s iZucstr is and Betula tortuosa a t h i g h e r e l e v a t i o n s ( S j o r s 1965b, Rune 1 9 6 5 ) , t h e l a t t e r f o r m i n g t r e e l i n e a t 600 t o 800 i n Lappmark.

T a i g a f o r e s t Taiaa woodland Lesotundra

A r c t i c

Tundra Zone Subarc t i c - Southern

fo res t - tund ra shrub tundra

Subarc t i c - Nor thern sub shrub tundra hummocky ( co t tong rass )

sedge-moss tundra , cush ion p lan t t und ra

herb-moss, moss sedge

A r c t i c - Southern

A r c t i c - Nor thern

Po lar Deser t Zone Southern and Nor thern herb-moss. herb- l ichen

The most ex tens ive reg ions o f d iscont inuous and c o n t i n u o u s p e r m a f r o s t i n a s s o c i a t i o n w i t h c l o s e d b o r e a l f o r e s t a r e i n E u r a s i a ( F i g . 1 ) . F o r e s t s o f P i m a obovata, Pinus sibirica, and Abies sibirtcn extend f rom eastern Europe across S iber ia w i t h Picen dominat ing vast areas o f cont inuous p e r m a f r o s t t e r r a i n . Abies s,ibirica i s i m p o r t a n t i n t h e t a i g a o f e a s t e r n Europe t o 63-65'N. I n t h e more c o n t i n e n t a l l a n d s , e a s t o f the Yenisey River , Abies i s i m p o r t a n t i n t h e f o r e s t s s o u t h o f 60-62' N (Hust ich 1966); most o f t h i s a r e a i s u n d e r l a i n by d iscont inuous permafrost . On b e t t e r d r a i n e d s o i l s , o f t e n w i t h o u t p e r m a f r o s t , pinus s i l v e s t r i s and P. sibirica predomina te ; t he l a t te r spec ies having a d i s t r i b u t i o n p a t t e r n more l i k e Abies sibiricu.

I n N o r t h A m e r i c a c l o s e d f o r e s t s o f l a r c h a r e uncommon, most stands o f Lariz Zaricinn o c c u r r i n g i n f e n s as sparse and open grown fo res ts (Hus t ich 1957, Rowe 1972, R i t c h i e 1960, 1962). I n c o n t r a s t , Larix fo rms vas t c losed fo res ts across eas tern S i b e r i a a n d i t i s an important genus i n t h e c l o s e d f o r e s t s o f European and c e n t r a l S i b e r i a . Luriz si.biriea predominates i n European USSR, L . sibirica and I,. duhurica (= L . p e Z i n i i l i n western and c e n t r a l S i b e r i a and L . dahurica w i t h o u t P i m a and Abies i n e a s t e r n S i b e r i a ( H u s t i c h 1 9 6 6 ) .

The p rev ious d i scuss ion has centered on t h e l a r g e s c a l e p a t t e r n o f v e g e t a t i o n i n r e l a t i o n t o l a r g e s c a l e p e r m a f r o s t c o n d i t i o n s . L e t us l o o k b r i e f l y a t a meso- o r m i c r o - s c a l e r e l a t i o n s h i p o f topography, permafrost features, and vegetat ion.

33

Near the southern limit of discontinuous permafrost , palsas ( ice mounds) typically form where surface peats dry i n summer, effectively reducing thermal conductivity. W i t h f a l l cooling and precipitation, the peats become saturated which increases thermal conductivity. This annual cycle resu l t s i n more winter cooling than summer heating, the net result being a negative heat balance resulting i n ice formation and preservation (Brown 1970, T.yrtikov 1959). These palsas w i t h their elevated peats are better drained and often thinly treed (Zoltai 1972. Zoltai and Pettapiece 1974, Zoltai and Tarnocai*l975). The relationship of permafrost and annual soil temperature regime t o a successional pattern o f forest vegetation (15 t o 20 - 250 yr) has been presented for central Alaska (Viereck 1970a, b ) . Viereck (1965) also discussed the relationship of Picea gZauca t o the local occurrence of ice lenses t h a t develop w i t h canopy closure. Similar cycles of vegetation in relation t o perma- f ros t have been described by Benninghoff (1952) a n d Drury (1 956).

These northern closed forests are low in biological production, except in the specialized habitats o f r iver terraces , del tas , and wetlands near lakes. Muskrats, beaver, moose, and waterfowl are the most productive animals; a l l of these in wetlands. The closed forests produce limited numbers of woodland caribou, wolf, fox, wolverine, marten, hare, and birds.

Open Woodland and Forest-Tundra

As climate becomes more severe poleward, perma- f ros t becomes more continuous and the rooting zone less favorable for t ree growth; fo res t s a re more open grown and t rees a re of lower stature. This region of "subarctic" forest stretches i n a broad arc across Canada, varying in width from ca.150 t o 5 5 0 h (Rowe 1972). In Newfoundland and Quebec, open stands of black spruce-lichen predominate in uplands. P-i.cca gZauca and Abies baZsamea occur locally as closed forests. Lowlands and poorly drained so i l s are generally covered w i t h stunted P7:caa rnr*r<r*na; Lar-i-x lar-i-&na forms s t r ip s along lake shores and streams. carex dominated fens and shrub dominated bogs with scattered black spruce cover many square kilometers (Hustich 1951, Sjijrs 1959). Similar ereas of lichen-woodland occur west of Hudson Bay, nor th of Great Slave Lake t o Great Bear Lake and to the lower delta area of the Mackenzie River (Hustich 1957, Ritchie 1959, Maikawa a n d Kershaw 1976, Kershaw 1978).

Fire plays a major ro le in these lichen-woodlands and forest-tundras (Rowe and Scotter 1973, Mai kawa and Kershaw 1976, Black and Bliss 1978). Without f i r e , a closed canopy fores t w i t h a feather moss understory develops in 200 yr . Following f l ' re , woodlands dominated by the lichens CZaclonia stcZZaris or Stereocaulon puschaZc develop. Exten- sive lichen mats reduce soil temperature t o levels t h a t may l imit t rue root g r o w t h , thus conserving the open nature of the woodlands. These lichen mats a l so reduce water flux and thus maintain soil water levels favorable t o t r ee growth where so i l s m i g h t otherwise be too dry t o support these open stands

(Kershaw 1978). The development of 1 ichen mats plays a key role i n maintaining these open stands of P i m a mariana.

In the lower Mackenzie River region, lichen- woodland i s more res t r ic ted due to the longer time required for lichen cover t o develop (150-2004 y r ) , the domination of low shrubs in the understory for many years due t o f iner t ex tured t i l 1 soi 1 s , and the presence o f cold so i l s due to permafrost (Black and Bliss 1978) ( F i g . 3 ) . Active layer depths averaged 1002 1 7 cm in "stands" 8 yr following f i r e , 51+ 22 cm in stands 30-115 y r , 437 4 cm i n stands 130-190 y r and 52+ 19 cm i n stands 240-285 y r a f t e r burning. Repeated f i r e s within these subarctic woodlands have l i t t l e e f f e c t on the understory vascular plant composition b u t a major impact on the lichens and mosses fo r many years (Black and Bliss 1978). Fire also plays a major role in the l ife history of Piem mariana by preparing a seed bed (Ahlgren 1959), opening the semi-serotinous cones (Vincent 1965), and al ter ing the thermal regime o f the soil (Rouse and Kershaw 1 9 7 1 ) . Fire i n the forest-tundra can eliminate tree establishment provided the general c l imate is in a cooling cycle (Nichols 1975, Black a n d Bliss 1978). Black (1977) calculated that only a 6-7 yr "window" occurs for seedling establishment following f i r e near tree l ine. Since re la t ive ly h i g h surface temperatures are necessary fo r seed germination, seedling establishment can be prevented d u r i n g cooler climatic periods (Black 1977). Massive f i r e s could effect ively force t ree l ine 50-100 km south, which helps to explain fores t and t ree l ine osc i l la t ion i n addition t o fores t advance during the warmer Hypsithermal Interval and the cooler climates which have followed (Ritchie and Hare 1971, Ritchie 1974). More recently, Ritchie (1978) has described vegetation change since deglaciation near Inuvik, NWT t h a t i s based upon sequential invasion of species (plant succession) rather than regional cl imatic change. Additional research i s needed i n order t o determine the relative roles of the fa i lure of t ree re - establishment following f i r e vs. cl imatic oscil la- tion in explaining post forest and t ree l ine boundaries i n the North.

In many areas the transition from forest-tundra to shrub t u n d r a resul ts in only the loss of ~icaa gluuca i n better drained uplands and r iver terrace locations (Drew and Shanks 1965) or the eventual f a i lu re of ~ i c e u n~rirzna t o maintain i t s e l f i n more poorly drained, cold soils with a shallow active layer (Larson 1965, 1971, 1972; Black and Bliss 1978). Because of this patterning, Sovl'et ecologists have generally considered shrub tundra a past of the subarctic (Andreev 1966, Aleksandrova 1970) or hypoarctic (Yurtsev 1966, 1972).

The transit ion from closed forest t o t u n d r a in Alaska i s complicated by the Brooks Range in the north t h a t prevents the normal transit ion t o open woodland and forest-tundra. a n d the low net radiation values o f western Alaska when a broad band o f t undra occurs where general climate indicates t h a t fo res t should be present (Hare and Ritchie 1 9 7 2 ) .

34

I n the no r the rn moun ta ins and up land p la teaus o f Fennoscandia, Betula kortuosa predominates i n t h e fo res t - tund ra . Open grown Pinus s i zves t r i s genera l l y occu rs as t he nex t l ower e leva t i on woodland (R6nning 1960, S j o r s 1965b, B luthgen 1970, Ka l l i o 1975) . Pe rmaf ros t p lays a m i n o r r o l e i n vege ta t i on pa t te rn , excep t i n mires where palsas occu r , p rov id ing e leva ted and somewhat d r i e r h a b i - t a t s ( R o s s w a l l e t a1 . 1975).

I n European USSR, t h e f o r e s t - t u n d r a ( l e s o t u n d r a ) i s formed by communities of RetuZa tortuosa and Pima excclsa (wes tern sec t ion) and P, obovata and L u r k s ibir ica i n t h e e a s t e r n s e c t i o n ( T i k h o m i r o v 1970). On t h e w e s t e r n s l o p e s o f t h e p o l a r U r a l - Mountains Betula to r tuma dominates wi th an under- s t o r y o f Juniperus s ibir ica, Rosa acicuZarCs, BetuZa nana, SaZix glauca, S. arhscuZa and var ious dwarf shrub heath species. To the sou th Pinus obovtxta dominates a t t r e e l i n e (700-800 m) w i t h l e s s e r amounts o f BetuZa tortuasa and Abies sibirica (Gorchakovsky and Shiyatov 1978).

L a r k danhurica dominates i n western and cent ra l S i b e r i a . On t h e e a s t e r n s l o p e s o f t h e U r a l s , L . s ibir ica vnr . sukuczewii predominates wi th an u n d e r s t o r y s i m i l a r t o t h a t o f t h e open fo res ts on the western s lope (Gorchakovsky and Shiyatov 1978) . The n o r t h e r n limit o f t r e e s o c c u r s n e a r Ary-Mas a long t he Novaya River (7Z030'N) on the Taimyr Penninsula (Nor in and Ignatenko 1975) . In t h i s con t inen ta l c l ima te ( January mean -33.80, J u l y mean 13.1OC), open l a r c h woodland (redkolesja), and very open woodland ( red ina ) occu r on t he va l l ey s lopes w i t h bog and spo t ted t und ra ( so i l - bo i l s ) on r i d g e s and p o o r l y d r a i n e d s l o p e s . A c t i v e l a y e r d e p t h s a r e c l o s e l y c o r r e l a t e d w i t h nano- and m i c r o - r e l i e f and p l a n t communi ty pa t te rns . In open l a r c h thaw averages 50-70 cm i n l a t e August, 30-50 cm under t rees, and 40 cm (cracks and depressions) t o 65 cm ( b a r e s o i l ) i n t h e s p o t t e d t u n d r a ( N o r i n and Igna- tenko 1975).

I n e a s t e r n S i b e r i a ~ a r i x dahurica ( L . ctxZcxnderil predominates except i n T r a n s l e n i a n S i b e r i a where t h e l o w s t a t u r e Pinus pmih occurs on mountain s lopes and the dec iduous t rees Chnsenin mncroZepis and ~ o p 1 ~ Z . u ~ s~avenZens i n v a l l e y s ( H u s t i c h 1966, Tikhomirov 1970). I n t h e m o u n t a i n s o f Kamchatka t h e t r e e l i n e i s dominated by Betula ermani a t elevat ions of 700-850 m. I n p l a c e s t h e r e a r e some Larix dnnhuricu and Hocu jezoensir: t r e e s t o a h e i g h t o f 8 - 1 6 m. The s h r u b l a y e r c o n s i s t s o f Pinus p m i Z a , Sorbus sambucifolia, A h u s f ru t icnsa , A . kmtoschat ica and &oziperus sibirica (Gorchakov- sky and Shiyatov 1978).

Within the open woodland and f o r e s t - t u n d r a , w i l d - l i f e i s even more r e s t r i c t e d , due t o t h e r e d u c e d p l a n t p r o d u c t i o n base. The m o s t c h a r a c t e r i s t i c an ima ls a re bar ren g round car ibou and r e i n d e e r w h i c h o v e r w i n t e r i n t h e open fo res ts where there i s an abundance of l ichens, sedges, and low shrubs. R i v e r d e l t a s a r e p r o d u c t i v e i n water fowl , muskra ts , moose, and beaver.

ARCTIC


H i s t o r i c a l l y , A r c t i c has r e f e r r e d t o t h o s e l a n d s beyond t h e n o r t h e r n c l i m a t i c limit o f t r e e g r o w t h . S c a t t e r e d i s l a n d s o f t r e e s may occur 20 t o 100 km poleward on southern s lopes and a l o n q r i v e r s w h e r e s o i l s a r e somewhat warmer and t h e a c t i v e l a y e r i s deeper i n summer.

C l a s s i f i c a t i o n o f t h e A r c t i c has been based upon zonal concepts i n t h e USSR (Aleksandrova 1970) and North America (Polunin 1951). Whi le tones o f c l i m a t e and assoc iated veaetat ion are more pronounced i n t h e S o v i e t Union (Andreev and Aleksan- drova 1979) because o f g r e a t e r c o n t i n e n t a l i t y than i n N o r t h Amer ica, more recent s tud ies i n t h e Canadian A r c t i c r e v e a l a m o s a i c p a t t e r n ( B l i s s 1975, 1977). The m o s a i c r e s u l t s f r o m d i f f e r e n c e s i n summer s o l a r r a d i a t i o n and r e s u l t a n t tempera- tu re reg ime , t he amount o f w a t e r r e t a i n e d o n t h e land fo l low ing snowmel t , and s o i l t e x t u r e and so development as inf luenced by bedrock geology.

I n mainland North America and presumably acros Eurasia, the boundary between forest and tund ra c o i n c i d e s w i t h t h e summer p o s i t i o n o f t h e A r c t i c

il

S

Front (Bryson 1966). Another important component o f t h e b i o c l i m a t e o f t h e N o r t h i s n e t r a d i a t i o n . The n o r t h e r n limit o f f o r e s t o c c u r s n e a r t h e 75- 80 kJ cm -2 i s o l i n e i n Canada and t h e 65-70 kJ cm -2 i so l i ne i n A laska (Hare and R i t ch ie 1972) . Ne t r a d i a t i o n f o r t h e g r o w i n g season dec rease i rap id l y i n g o i n g f r o m c l o s e d b o r e a l , e v e n w i t h s p r i n g l a n d , and f i n a l l y t o t u n d r a , The low albedo o f c l o s e d fo res t , even w i th sp r ing snow, vs . the tundra and t h e s t r u c t u r e o r r o u g h n e s s o f v e g e t a t i o n ( f o r e s t v s . s h r u b t u n d r a ) , a l l i n f l u e n c e t h e r a d i a t i o n b a l a n c e and t h e r e f o r e t h e b i o c l i m a t e p o t e n t i a l f o r p l a n t g rowth and ne t p lan t p roduc t ion (Hare and R i tch ie S 972).

For purposes o f t h i s p a p e r , t h e A r c t i c i s d i v i d e d i n t o Low and H igh Arc t i c based upon c l imat ic d i f f e rences , pe rmaf ros t cha rac te r i s t i cs , vege ta t i on s t r u c t u r e . and w i l d l i f e d i v e r s i t y ( T a b l e 2 ) .

Low A r c t i c

The Low A r c t i c i s c h a r a c t e r i z e d b y c l o s e d v e g e t a - t i o n o f shrubs, herbs, mosses, and l i c h e n s ; b a r e ground i s g e n e r a l l y a m i n o r f e a t u r e . In most p lan t communi t ies there i s some component o f woody vege ta t i on , rang ing f rom ta l l sh rubs (2 -5 m h i g h ) o f SaZk> RetuZa, and AZnus along streams and steep banks t o d w a r f s h r u b s ( 5 - 2 0 cm h i g h ) o f Lcdum, Vaecin-im, Salix, and Empetrum on e levated s i t e s w i t h l i t t l e w i n t e r snow cover . The dwar f shrubs also occur as a component w i t h i n c o t t o n - grass tussock communit ies and l o w shrub lands . These landscapes w i t h t h e i r c o n t i n u o u s o r n e a r cont inuous cover o f v a s c u l a r p l a n t s and crypotogams, o f t e n w i t h a strong component o f t a l l t o dwar f sh rubs , a re genera l l y ca l l ed t und ra (F ig . 4 ) .

C h a r a c t e r i s t i c

Mean annual temperature ("C) J u l y mean temperature (OC) Length of growing season (months) Accumulated degree days (OOC) Mean a n n u a l p r e c i p i t a t i o n (mm) Mean annual temperature of permaf ros t

A c t i v e l a y e r d e p t h - g rave ls (m)

P lan t cove r - tundra (%)

F lower ing p lan ts (#spec ies ) Mammals ( # species) Breed ing B i rds ( # spec ies)

( - I O t o -2Om)

- peat and c l a y (m)

p o l a r d e s e r t s (%)

Tal l Shrub Tundra

L a r g e r i v e r s i n a r c t i c A l a s k a , m a i n l a n d Canada, southern Greenland, and mainland Eurasia have sand and grave l bars as w e l l as s teep s lopes tha t a re t y p i c a l l y c o v e r e d w i t h t a l l s h r u b s . SaZix almens fs predominates i n w e s t e r n Canada and Alaska on coarse g rave ls and sands (B1 i s s and Cantlon 1957, Drew and Shanks 1965, Gill 1973). Associated shrubs on f i n e t e x t u r e d s o i l s , a n d o f t e n as an unders to ry to the f e l t l e a f w i l l o w , i n c l u d e S a l i x Zanata, S. r7:chard- sonii , S. gLauca, Betula glandulosa, and AZnus c r i s p . These Communities a r e s t r o n g l y c o r r e l a t e d w i t h warmer s o i l s i n summer, s o i l s w i t h b e t t e r d ra inage and deeper ac t i ve l aye rs (1 -2m) . These communities have deep w i n t e r snow t h a t m e l t s e a r l y i n s p r i n g . T h e r e i s o f t e n a r i c h u n d e r s t o r y of grasses and herbs. Moose and a r c t i c ground s q u i r r e l s as w e l l as p tarmigan and arc t ic hare are commonly found i n t h i s l u s h a r c t i c v e g e t a t i o n .

35

Table 2. P h y s i c a l a n d b i o l o g i c a l c h a r a c t e r i s t i c s o f t he Low and H igh Arc t l ' c

Communities of t a l l shrubs (hyoarc t i c shrubs) a re a c o n s p i c u o u s f e a t u r e a l o n g r i v e r s and steep s lopes w i t h i n t h e S i b e r i a n and Chukotka provinces or d i v i s i o n s o f t h e A r c t i c ( A n d r e e v and Nakhabtseva 1974, Andreev and Aleksandrova 1979). I n t h e Yara- Ind ig i r ca subprov ince , Betula exqizis, S a Z k gZauca, S. Zanata, and AZnus fruticosa o c c u r a l o n g r i v e r s . I n t h e Kolyma subprov ince w i th inc reas ing snow cover, shrub communit ies o f BetuZa exiZis and A h u s f m t i c o s a o c c u r a l o n g r i v e r s i n t h e s o u t h e r n s e c t i o n w h i l e w i l l o w s c r u b o f SaZix ataxensis, S, puZchra, S, gZuuca, and S, lunata predominate i n t h e m i d d l e sec t i on . SaZCx puZchra, S. alaxensis and RctuZa exiZis a r e common i n t h e f a r e a s t e r n p r o v i n c e o f C h u k o t k a . N o t e t h e s t r o n g f l o r i s t i c t i e s i n t h e tund ra vege ta t i on of nor theas te rn As ia and Alaska, t he T ransber ing ian f l o r i s t i c e lemen t (Yu r t sev 1972) .

Low Shrub Tundra

W i t h i n t h e f o r e s t - t u n d r a , b i r c h and w i l l ow sh rubs 40-60 cm i n h e i g h t a r e common. Beyond t h e limit o f trees, low shrub tundra predominates as t h e f i r s t t y p e o f t u n d r a v e g e t a t i o n i n many u p l a n d s i t e s . I n western A laska and the Mackenzie River Del ta reg ion o f Canada, va r ious comb ina t ions o f BetuZa nana ssp. exiZis, SaZix gZauca, S. puZchra and S. Zanata ssp.

Low A r c t i c H i g h A r c t i c

-12 t o -9 -19 t o -16 7 t o 10 3 t o 6 3 t o 4 1 t o 2 . 5

300 t o 1000 150 t o 600 150 t o 350 50 t o 200

-4 t o -2 -13 t o - 1 0 1 t o 2 0.7 to 1 .2

0.3 t o 0.6 0 .2 t o 0.6 80 t o 100 80 t o 100 """ 0 t o 10

300 t o 600 50 t o 150 6 t o 20 3 t o 8

40 t o 70 5 t o 30

ri.cFmclsnnii p r o v i d e an open canopy. I n te rspe rsed are c lumps o f Carex bigeZntiii, Erfophorum vaqqinatwn, scat te red g rasses and fo rbs . Wi th in the moss and l i chen mat , vary ing amounts o f dwarf (sub-shrubs) shrubs (10-20 cm h igh) . most ly heath spec ies, are common. These i n c l u d e Vuacefnium vitis-idaeu, V . uZiginosum, k n p e t m m hermaphroditwn, E . nigrwn, Ledum paZustra Ssp. decumbens, Arctnstnphglou m h a , A. aZpina, Caasfope tetragonn, Rubus chnrme- moms and saZis ssp. (Hanson 1953, H e t t i n g e r e t a l . 1973, Corns 1974). These communit ies are common on moderately wel l drained uplands and s lopes where t h e r e i s t y p i c a l l y 25-50 cm of snow cover. With a t h i c k v e g e t a t i o n m a t , t h e a c t i v e l a y e r i s s e l d o m more than 35-50 cm deep by August.

I n t h e c e n t r a l and eas tern Canad ian Arc t i c , low shrub tundra i s l e s s common, t h e r e s u l t of t h i n n e r snow c o v e r a n d s t r o n g a b r a s i v e w i n d s i n w i n t e r (Sav i l e 1972) . The predominate shrubs are BetuZa qZanduZosa and Sa2-i-x qLauca a long w i th t he dwar f shrub heath spec ies as i n the west. These shrub communit ies are found on steep warm s lopes w i th 0.5-1 m o f snow c o v e r i n t h e C h e s t e r f i e l d I n l e t area west o f Hudson Bay, no r the rn Quebec, and s o u t h e r n B a f f i n I s l a n d ( P o l u n i n 1 9 4 8 ) . S i m i l a r shrub communit ies dominated by BetuZa gZanduZosa and seve ra l spec ies o f SaZix e x t e n d t o 74ON i n west Greenland, but on ly to 62"N i n eas t Green land , due t o i t s c o l d e r c l i m a t e away from the Labrador Current (Bocher 1959, Sdrensen 1943).

Across the USSR, low shrub tundra i s common i n the ro l l i ng up lands beyond fo res t - tund ra ( sub - arctic zone). Low shrubs (50-60 cm) of BetuZa m a , SaZiz Zanata, S. glauca, and S. phyZicf foZ<a and many o f the dwar f shrub heath spec ies p rev ious- l y descr ibed for Nor th Amer ica predominate . (Andreev and Aleksandrova 1979). Since these communit ies of the southern tundras are dominated by species common t o t h e b o r e a l f o r e s t , S o v i e t s c i e n t i s t s r e f e r t o t h e s e s h r u b and r e l a t e d communi t ies as compr is ing the subarct ic (A leksan- drova 1970, 1971, Andreev and Nakhabtseva 1974). Species common t o t h e b o r e a l f o r e s t and tundra a re re fe r red t o as hypoarct ic spec ies (Yur tsev 1966) .

36

Throughou t t he range o f l ow sh rub t und ra re in - dee r o r ca r ibou a re common i n summer. These lands a r e a l s o i m p o r t a n t h a b i t a t f o r s m a l l r o d e n t s ( m i c r o t i n e ) and many spec ies o f g round nes t ing b i r d s i n c l u d i n g p t a r m i g a n .

Cottongrass Tussock - Sub Shrub Tundra

Across western North America and Siber ia there a re vas t a reas o f t h i s community. I n t h e USSR t h e s e a r e c a l l e d hummocky tundra and i n N o r t h America tussock tundra. Eriophomm vaginaturn tussocks a re genera l l y 15-30 cm high, 15-25 cm across, and spaced 15-60 cm apar t . Large areas of western and northern Alaska (Hanson 1953, Church- h i l l 1955, B l i s s 1956, B r i t t o n 1957, Johnson e t a l . 1966), and 1 im i ted a reas o f t h e N o r t h w e s t T e r r i t o r y (Larsen 1965, Corns 1974) are covered with t h i s community. These communit ies are commonly found on r o l l i n g t o p o g r a p h y and smal l basins and val ley f l o o r s where s o i l d r a i n a g e i s i n t e r m e d i a t e and the a c t i v e l a y e r i n A u g u s t i s 30-50 cm deep. P r o s t r a t e shrubs o f Betula nana s s p . e x i l i s are common a long w i t h numerous dwarf shrubs o f v a r i o u s s p e c i e s o f heath (Ledm, Empal-rum, Vaecin.l:um, Fmptruml. MOSS- es i n c l u d i n g Sphagnum species and l ichens form a dense carpet between the tussocks. The sedges Carex higaZnwi i and C. lugans are common a l o n g w i t h t h e a r c t i c g r a s s Arctucyrostis 2atI;foZia and numerous species o f f o rbs .

These communities are some of t h e r i c h e s t i n p l a n t s p e c i e s d i v e r s i t y . They a r e a l s o f a v o r i t e f e e d i n g grounds i n e a r l y summer f o r c a r i b o u and re indeer w h i c h r e l i s h t h e t e n d e r and n u t r i e n t r i c h new shoots o f ~riophorum. Arc t ic m ice ( lemming) , and vo les a re common to t hese a reas , as are severa l spec ies o f g round nes t i ng b i rds .

Ac ross S ibe r ia Eriophorurn vaginatun! hummocky t u n d r a s a r e r e s t r i c t e d t o t h e s o u t h e r n s u b a r c t i c zone (Andreev and Aleksandrova 1979). I n t h e K o l y - ma subprovince o f t h e S i b e r i a n P r o v i n c e and i n t h e Chukotka Province carex Zugcns i s an impor tan t component as are the dwarf heath shrubs.

Sedge-Moss and Sedge-Grass-Moss Tundra

The F inn i sh word t und r i and the Soviet word tundra were o r ig ina l l y used to descr l 'be wet land areas dominated by sedges and grasses. Only limited w e t l a n d s o c c u r i n t h e m o u n t a i n s and upper foot- h i l l s o f a r c t i c A l a s k a and the Yukon T e r r i t o r y ( B r i t t o n 1957, H e t t i n g e r e t a l . 1973). They domina te on t h e C o a s t a l P l a i n i n A l a s k a ( B r i t t o n 1 9 5 7 , Webber and Walker 1975) and the coastal areas of t h e Yukon T e r r i t o r y and the Mackenzie Del ta o f t h e N o r t h w e s t T e r r i t o r y ( H e t t i n g e r e t a l . 1973, Corns 1974). Eastward across the NWT, wet sedgelands o c c u r , b u t w i t h t h e dominance o f rocky Precambrian l a n d s , t h i s t u n d r a t y p e i s l o c a l i z e d ( L a r s e n 1965, 1972). Where d r a i n a g e i s impeded, deep peats 2-10 m develop and on these sur faces Caras aquatiZis, c, chordorrhiza, C. rarifZora, C. rotunda, C. memmbran- mea , E r i o p h o m angustifolium and E. scheuchzeri predominate. The grasses f l r c tapws t i s ZatifoZia, Poa arctica and ncschampsia cacspitosa o c c u r i n t h e b e s t d r a i n e d s i t e s , Dupontia f i s h m i and Alapecums

aZpinus i n m o i s t s i t e s t o s h a l l w a t e r and Arw5?phila fu l va i n s t a n d i n g w a t e r . Common herbs i nc lude Cultha pa2ustrri.s ssp. arctica, ChrysospZe- n i m tatrandrwrc, Pedicularis sudetlka, Petusites f r i g i d u s and severa l spec ies of Saxifraga and Pinyuioula ( B r i t t o n 1957, Corns 1974).

The shal low waters o f lakes and ponds c o n t a i n Menyanthes tri:foZ?hba, Equisetum variegatum, Poten- t i l l a palus tr i s , AretophiZa fuZva and Hippuris vulgaris wi th spec ies o f Carex and Epiaphorwn where water i s on ly 10-20 cm deep.

These sedge and grass wet meadows have a n e a r l y cont inuous cover o f mosses i nc lud ing seve ra l spec - i e s e a c h o f ,Sphagnum, Drepanocladus, Alacnmnium, r:a%%iargon and ni-lrichwrr. Other common mosses a re Mcesia triquetra and Tornenthypnurn nitens; l i c h e n s seldom occur other than Peltigeru aphthosa on hummock tops .

I n many a r e a s , r a i s e d c e n t e r o r r a i s e d rim po ly - gons occur. The t roughs ( t o p o f ice-wedges) are dominated by sedges and the elevated si tes ( 3 0 - Z O O cm) are covered w i th dwar f shrub heath spec ies , and p r o s t r a t e o r l o w s h r u b s o f SaLix and Betula. S p e c i e s d i s t r i b u t i o n v a r i e s g r e a t l y o v e r s h o r t d i s t a n c e s i n r e l a t i o n t o s o i l w a t e r c o n t e n t , so71 a e r a t i o n , a c t i v e l a y e r d e p t h , and d e p t h o f w i n t e r snow cover.

Across S iber ia there a re vas t wet lands o f sedges. In the Ob-Yen ise i subprov ince , wet lands (mi res) are dominated by arc.^ yZobuZaris i n t h e s o u t h e r n p o r t i o n , C. ratundata i n t h e m i d d l e , and I:. chordnrrkizae i n t h e n o r t h e r n p o r t . i o n o f the sub- a r c t i c zone. To t h e n o r t h i n t h e a r c t i c zone where woody v e g e t a t i o n i s m i n o r , Carex stuns dominates. To the wes t i n t he Yana- Ind ig i r ka sub - province, mires are dominated by Carm s*ans and Er*iophorum anpst i jbl%um. I n many areas Arcto- p h i h fuZva occurs i n s h a l l o w w a t e r s o f l akes and ponds (Andreev and Aleksandrova 1979).

These wet lands are very important feeding and n e s t i n g s i t e s f o r numerous species o f w a t e r f o w l and sho re b i rds . They a r e a l s o i m p o r t a n t summer range f o r car ibou. Because o f t h e w e t s o i l s , t h i c k moss cover and deep sa tura ted peats , the a c t i v e l a y e r i s seldom more than 20-30 cm deep by l a t e August.

Cushion Plant-Herb-Lichen

I n t h e m o u n t a i n s o f t he Yukon T e r r i t o r y and Alaska, wind-swept s lopes and r idges are of ten dominated by R~yas octopetala, 1). integrifnZ7:a, numerous grasses, sedges, and small clumps or r o s e t t e s o f s p e c i e s o f Draba, Saxi fraga, Arenaria, and Carastiurn ( B r i t t o n 1957, Drew and Shanks 1965, Johnson e t a1 . 1966, H e t t i n g e r e t a1 . 1973). Species o f the l i chen genera Cetraria, Cornicu- laria, and Alectorin a r e a1 so impor tan t . P lan t cover i s much l e s s as i s p l a n t p r o d u c t i o n when compared w i th the p rev ious communi t ies . Dryas dominated communities i n u p l a n d g r a n i t i c r o c k a r e common i n t h e u p l a n d s o f the Booth ia and M e l v i l l e pen insu las o f t h e N o r t h w e s t T e r r i t o r i e s , Canada.

37

I n t h e U r a l M o u n t a i n s and o ther no thern mounta in systems o f t h e USSR, nryas and l i chen dominated communit ies are common. The a r c t i c zone i s o f t e n charac ter ized by hummocky tundra w i t h Carex ens?:- f o l i a ssp. arctfs<bCrica, Dryas octopetaZa, mosses, and l ichens in the Ob-Yenise i Subprov ince (Andreev and Aleksandrova 1979). I n t h e Kolyma Subprovince Diapensia obovata, SaZfx poZaris, /?pyas punctata, and Alopecurus aZpinus a long w i th smal l herbs , mosses, and l i c h e n s a r e common. On the Taimyr Pen insu la ex tens ive a reas a re covered w i th a moss- Dryas-sedge tundra i n a " f r o s t - b o i l " o r " s p o t t e d tundra" pat tern (Matveyeva 1972, Pospelova 1972, Nor in and Ignatenko 1975) .

These communities dominated by Dryas, d r y s i t e s p e c i e s o f Carex, and p r o s t r a t e s h r u b s o f SaZix, mosses, and l i c h e n s f o r m one o f the most common communit ies i n t h e H i g h A r c t i c as discussed below.

H i g h A r c t i c

I n c o n t r a s t w i t h t h e c o n t i n u o u s c o v e r o f vegeta- t i o n o f t h e Low A r c t i c , t h e H i g h A r c t i c i s c h a r a c - t e r i z e d by i t s l i m i t e d p l a n t c o v e r , s p a r s e n e s s of w i l d l i f e e x c e p t i n l o c a l i z e d a r e a s ; a general appearance o f b io log i ca l ba r renness (Tab le 2 . ) . The H i g h A r c t i c , m o s t l y i n Canada (F ig . l ) , can be d i v i d e d i n t o s m a l l a r e a s of tundra (sedge-moss, dwar f shrub heath, and cot tongrass tussock) , large areas o f spa rce vege ta t i on (po la r semi -dese r t ) and l a r g e a r e a s o f l i t t l e o r no v e g e t a t i o n ( p o l a r dese r t ) (B1 i s s e t a1 . 1973, 51 i ss 1975) . As a r e s u l t o f less p lan t cover , the pa t te rned g round fea tu res (Washburn 1956) of a permafrost dominated t e r r a i n ( s o r t e d and non-sor ted po lygons and s t r ipes , so l i f l uc t i on t e r races , mass ive i ce -wedge pa t te rns , and s o i l hummocks) a r e a more conspicuous feature.

Tundra

On ly smal l a reas o f sedge-moss t u n d r a o c c u r i n t h e Queen E l i z a b e t h I s l a n d s (> 2 % ) (Babb and B l i s s 1974). Lowlands with impeded drainage and coastal a reas w i th se r ies o f ra i sed beaches re ta in snow m e l t w a t e r s , t h i s p e r m i t s t h e e x t e n s i v e g r o w t h o f t h e sedges C a r m stuns, C. memhmnacea, Eriopharm scheuchzcri and E. e r i s t e (Po l un in 1948, Savi l e 1964, Brassard and Longton 1970, Muc 1977, B l i s s and Svoboda 1979a, b ) . Mosses o f t he genera Distichwn, Jhiwn, Ditrichwn, Tomenthypnwn, Drqmno- cZadu.s, AuZacomnim and ~ y p n u m are abundant (Vitt 1975, Vitt and Pakar inen 1977). L ichens are very m ino r i n t hese we t lands . W i th sa tu ra ted , pea ty s o i l s , t h e a c t i v e l a y e r i s more shal low i n these areas (Fig. 5). These meadows, b i o l o g i c a l l y t h e mos t p roduc t i ve s i t es i n t h e H i g h A r c t i c , s u p p o r t muskox, Peary's caribou, brown lemming i n t h e s o u t h e r n a r c t i c i s l a n d s , and numerous species o f water fowl and shore b i rds.

Small meadows of grasses, sedges, and mosses occur on Sval bard (Rdnning 1965). Herb-grass meadows of Poa aZpigena, Azopecurus alpinus, Luzula confusa, and severa l spec ies o f s w i f r a g a i n i n t e r - f l u v e Communities and sedges i n s t ream va l l eys a re p resen t i n t he no r the rn Ta imyr Pen insu la , USSR (Elatveyeva e t a l . 1975).

Dwarf shrub heath communi t ies wi th var ious com- b i n a t i o n s o f Cussiope Getragom, Vaeciniwn uZigin- osum, Rhododendron lapponiaum, SaZix arctica, and myas in t egAfoZ ia o c c u r t o 72'-73ON i n e a s t Green- l and and t o 75'-760N i n west Greenland (Sieden- faden and Sdrensen 1937, Sdrensen 1943, Oosting 1948). Heath communit ies are species poor i n t h e Canad ian H iah A rc t i c , t yp i ca l l y domina ted by L'msiopc tetragons and l e s s e r amounts of SaEx arctica, Dryus integrifoZia, and Carex misandpa (Brassard and Longton 1970, Beschel 1970, B l i s s e t a l . 1 9 7 7 ) . These communities occur where snow me l t s 1-2 weeks l a te r t han ave rage and on warmer south o r wes t - fac ing s lopes (F ig . 5 ) .

Polar Semi-desert

Plant communit ies dominated by cushl 'on plants

about 55% o f the Canadian mainland High Arct ic and ( ~ r y a s , SaZix, iymi fraga oppositifoZial. cover

t h e s o u t h e r n a r c t i c i s l a n d s . Cover o f f l o w e r i n g p lan ts genera l l y ave rages 10 t o 20%; l i chens and mosses prov ide an a d d i t i o n a l 30 t o 50% cover. These communities occur on r o l l i n g s l o p e s and exposed uplands where wjnter snow cover i s s h a l l o w a n d t h e s o i l s i n summer a r e w e l l t o i m p e r f e c t l y d r a i n e d ( B l i s s and Svoboda 1979b).

I n t h e e a s t e r n a n d c e n t r a l Queen E l i z a b e t h Islands, areas dominated by nryas integri fol iu , SaZi..?: arctica, S m i f r a g a oppos-i.tifoZia, Carer m y ' - dina, and l i chens occu r on sandy and g r a v e l l y r a i s e d beaches near the sea and on warmer s lopes w i t h w i n t e r snow c o v e r o f 50-100 cm ( S a v i l e 1964, Brassard and Longton 1970, Beschel 1970, Babb and B l i s s 1974, Svoboda 1977).

Dryas dominated communit ies occur on Svalbard (78'N) i n w i n d e x p o s e d s i t e s and i n areas o f deep-

petula occur (Rbnni np 1965) . e r snow Cussiope, Susalix polarlk, and Dryas octo-

Al though these communi t ies a re less p roduc t ive than t he t und ra sedqe and grass meadows, they do suppor t Peary 's car ibou and l i m i t e d numbers o f muskox, co l la red lemming, and a few spec ies o f n e s t i n g b i r d s .

I n t h e w e s t e r n Queen E l i zabe th I s lands where s i l t y loam t o c l a y loam so i l s p redominate , moss- l ichen-herb communi t ies predominate (F ig . 6 ) . The number o f s p e c i e s i s r e d u c e d , as i s p l a n t h e i g h t . Much more open ground i s p r e s e n t and c rus tose l i c h e n s become more i m p o r t a n t ( B l i s s and Svoboda 1979a). The domina te f l ower ing p lan ts i nc lude LuzuZa conjinsa, L . nivaZis, Papaver' rad ica tm , A Zopecurus alp-inus, Cerastiurn urct;icum, Iianunculus snbinei, and numerous species o f Dr>ubu and $mi- fruLga. The f o r b s a r e m o s t l y t i n y c l u m p s o r r o s - e t t e s w i t h compact stems and f l o w e r s w i t h i n 1-2 cm o f t h e s o i l s u r f a c e . The woody species saliz arctica and Drljus in t egr i fo l ia a r e r e s t r i c t e d t o on l y t he warmes t s i t es . A l thouqh to ta l p lan t cover i s l i m i t e d ( > 20% f l ower ing , 50-70%, l i c h e n s and mosses) i n b i o m a s s , t h e a c t i v e l a y e r i s as deep as i n many tundra communit ies of t h e Low A r c t i c (compare Figs. 4 and 6 ) .

Vegeta t ion somewhat s i m i l a r t o t h i s has been

d e s c r i b e d f o r Cape C h e l y u s k i n a t t h e t i p o f t h e Taimyr Peninsula (77O 43'N) (Matveyeva and Chernov 1976) . These authors termed the area po lar deser t though i t i s r i c h e r i n s p e c i e s t h a n m o s t a r e a s examined t o d a t e i n t h e Canadian High Arct ic .

Polar Deser ts

The most bar ren landscapes o f sandy s o i l s , a l k a - l i n e c l a y f l a t s , c o a s t a l and up land s i t es w i th massive sor ted po lygons and s t r ipes have 1-5% t o t a l p l a n t c o v e r . I n many areas vascu la r ( f lower - i ng ) p lan ts a re spaced 1 -5 m a p a r t and each p l a n t i s 0.5-2cm i n s u r f a c e a r e a . The most common spec ies a re Papaver rudicaturn, Cerastim arcticum, Draba corymbusa, Saxi fraga ccmua, S, o p p s - i t i f u l i a , Phippsia algidu, Al.opecums alpinus, and PuccineZZia angustatu. Only i n small areas (1-2ha) below snow- banks are there mats o f moss (10-30% c o v e r ) w i t h 8-12 species o f f l o w e r i n g p l a n t s ( F i g . 7 ) ( B l i s s e t a l . 1979) . E leven spec ies o f f lower ing p lan ts were r e c o r d e d a t 350 m on Somerset Island and 10 species a t 900 m a t Lake Hazen, E l l esmere I s land (Sav i l e 1959).

A t 26 s i t e s sampled on f i v e i s l a n d s w i t h i n t h e Cen t ra l H igh A rc t i c , vascu la r p lan ts ave raged 2% cover , l i chens 0.9%, and bryophytes 0.3%. Only i n s n o w f l u s h s i t e s was t o t a l p l a n t c o v e r more than 0.5 t o 5%. P lan t cove r was more s i m i l a r t o semi- deser t lands , vascu la r p lan t cover lo%, l i c h e n s lo%, and bryophytes 12% (Bl iss e t a l . 1979). Polar d e s e r t s w i t h t h e i r s p a r c e p l a n t c o v e r have been d e s c r i b e d f o r Novaya Zemlya (Aleksandrova 1959) and t h e n o r t h e r n p o r t i o n s o f F r a n z J o s e f Land and t h e New Siber ian Is lands (Severnya Zemlya) (A leksan- drova 1970).

Under such bar ren cond i t ions insec ts a re g rea t ly reduced and b i r d s and lemming a re ra re , a l t hough a few do occur nea r snowf lush s i t es . Peary ' s ca r ibou , muskox, a r c t i c f o x and o t h e r l a r g e r mammals a re found on ly as they move across these barrens seek- ing a reas o f h i g h e r b i o l o g i c a l p r o d u c t i o n . The a c t i v e l a y e r i s o f t e n 50-60 cm i n depth by mid-

A u g u s t , t h e r e s u l t o f r e l a t i v e l y w e l l d r a i n e d so l i t t l e o r no p l a n t c o v e r and o r g a n i c m a t t e r accur, l a t i o n , y e t s o i l s t h a t a r e o n l y 2O-3'C a t -10 cm.

Summary

From t h i s d i s c u s s i o n i t shou ld be apparent tha t s u b a r c t i c and a rc t i c l ands have a low d i v e r s i t y of species and a low b i o l o g i c a l p r o d u c t i o n . T h e r e i s a v e r y s i g n i f i c a n t p o l e m r d r e d u c t i o n i n l a n t p r o - duc t i on w i th in t hese vas t a reas (Tab le 37. With r e d u c e d b i o l o g i c a l p r o d u c t i o n t h e r e i s a co r res - p o n d i n g r e d u c t i o n i n t h i c k n e s s o f t h e o r g a n i c l aye r . A l though the po la r semi -dese r t s and p o l a r deser ts o f t he H iqh A rc t i c have l ess ene rgy i npu t and c o l d e r s o i l s i n summer, depth o f t h e a c t i v e l a y e r i s as g r e a t as i n t h e Low A r c t i c . Some p l a n t c o m m u n i t i e s ( t a l l s h r u b t u n d r a , i s o l a t e d f o r e s t s t a n d s ) . c a n b e c o r r e l a t e d w i t h a deeper a c t i v e l a y e r , b u t i n g e n e r a l a r c t i c p l a n t communi- t i e s seem t o be p o o r l y c o r r e l a t e d w i t h d e p t h of t h e a c t i v e l a y e r .

REVEGETATION OF SUBARCTIC AND ARCTIC LANDS


Revege ta t i on and genera l rehab i l i t a t i on o f d i s - t u rbed l ands have been p rac t i ced f o r yea rs i n temperate regions. It i s o n l y w i t h i n t h e l a s t 8- 10 y e a r s t h a t a corresponding technology has begun t o be deve loped to res to re no r the rn l ands . Th i s r e s u l t s m a i n l y f r o m p e t r o l e u m e x p l o r a t i o n a n d p r o - duct ion, though more recent ly some min ing opera- t i o n s , r o a d and a i r s t r i p c o n s t r u c t i o n , and commun- i t y development are beginning to use these tech- n iques. A l though the 1 i t e r a t u r e on r e v e g e t a t i o n i n t h e t a i g a and tundra i s no t l a rge , two rev iews on North American research have been prepared (Johnson and Van Cleve 1976, Peterson and Peterson 1977). The annotated b ib1 ioqraphy on permaf ros t , vege ta t i on and w i l d l i f e ( R o b e r t s - P i c h e t t e 1 9 7 2 ) con ta ins re fe rences t o some o f t h e e a r l y s t u d i e s .

To da te , the most success fu l res to ra t ion p rograms

P l a n t Community

Table 3. N e t p r i m a r y p r o d u c t i o n f o r d i f f e r e n t A r c t i c E n v i r o n m e n t s . Data are aboveground est imates only

Ne t p lan t p roduc t i on (g m-')

R o s e t t e p l a n t

Moss-herb Cushion plant-moss

Wet sedge-moss Cottongrass-dwarf heath Low shrub-dwarf heath

Vascular P lants Bryophytes Tota l

Po la r Deser t 0.1-1 il

Polar Semi-desert 3-1 5 1-30 5-35 5-50 1-20 5-50

A r c t i c Tundra 35-1 00 15-1 00 50-1 50 40-75 30-1 30 100-1 75 75-1 50 30-50 100-200

39

have s ta r ted by de te rm in ing t he ro le of n a t i v e spec ies i n p lan t success ion , and where p o s s i b l e i n c o r p o r a t i n g some o f t h e s e s p e c i e s i n t h e seed mixes. As will be seen, the use o f nat ive spec ies i s i m p o r t a n t i n t h e n o r t h e r n b o r e a l f o r e s t and fo res t - tund ra , and becomes more i m p o r t a n t i n t h e t u n d r a s o f t h e Low A r c t i c and the po la r semi -dese r t s o f t h e H i g h A r c t i c .

The p r i m a r y o b j e c t i v e s o f t h e s e s t u d i e s h a v e been to de termine : 1 ) what spec ies and species m i x will p r o v i d e an adequate cover t o h o l d t h e s o i l , 2 ) s u c c e s s f u l l y o v e r w i n t e r and regrow i n successive years ; and 3 ) ma in ta in popu la t ions o f the spec ies through natura l reseeding. Seeding and f e r t i l i z e r l e v e l s have a1 so been determined.

Taiga

W i t h i n t h e n o r t h e r n c l o s e d b o r e a l f o r e s t and open woodland, the grasses CaZamagrostis canadensis, Arctagrostis ZatifoZia, sedge species o f Carex and E r i o p h n m , f i reweed (EpiZnbizurt anplstiJoZizm) h e d m groenZandicum and ArctostaphyZos mbra and the shrubs AZnuv crisp, SaZix ssp. are the t y p i c a l p i o n e e r s p e c i e s i n d i s t u r b e d l a n d s ( R e i d 1977, Hernandez 1974). Culmqrost is canadensis fo rms ex tens ive g rass lands in sou th cen t ra l A laska (M i t che l l and Evans 1966) and in wes te rn A laska (Hanson 1951 ) .

R e v e g e t a t i o n s t u d i e s w e r e i n i t i a t e d a t e i g h t s i t e s w i t h i n f o r e s t e d l a n d s n o r t h o f Fairbanks, Alaska i n 1970 and 1971 (Van Cleve 1973), and a t t h e b u r i e d h e a t e d p i p e l i n e t e s t s i t e a t F a i r b a n k s i n 1970 (McCowan 1973) . I n Nor the rn Canada s i m i l a r research was i n i t i a t e d a t Norman Wells, NWT i n 1971 (Wein 1971, Hernandez 1973a), a t Sans Sau l t , NWT i n 1971 (Dabbs e t a l . 1974, Younkin 1976), and a t I n u v i k , NWT i n 1971 (Younkin 1971, 1976).

A f te r two summers o f growth, the grasses Arctared and Boreal creeping red fescue (Festuca rub& and Nugget Kentucky bluegrass ipoa pratensis) grew best on t h e berms o f co ld ( -9 .5 C ) and ho t (18OC) s imu la ted gas p i p e l i n e s a t t h e t e s t f a c i l i t i e s a t Norman Wells (65O17'N) (Hernandez 1973a). The t e s t s a t t h e Sans S a u l t s i t e (65O40 'N) a lso w i th in the bo rea l f o res t , abou t 90 km n o r t h o f Norman Wel ls showed t h a t a f t e r f i v e y e a r s t h e g r a s s e s D u r a r sheep fescue (Festuca ovina) , Meadow f o x t a i l (flZapecums pratensis), F r o n t i e r r e e d c a n a r y - grass (PhaZuris armndinacea), Meadow fescue (Festuca ezat ior) , Borea l c reep ing red fescue (Festuca rubru) Kentucky, b luegrass (Poa pratensis), and Fowl b luegrass (Poi paZuetris) grew best (Younkin 1976) (Tab le 4 ) .

A t t h e end o f t he seven th g row ing season a t h i c k m a n t l e o f g r a s s e s c o v e r e d t h e t e s t p l o t s a t Norman Wel ls . The most abundant grasses were the fescues and t h e n a t i v e b l u e j o i n t g r a s s (~aZmugrastis canadensis).

The r e v e g e t a t i o n p l o t s a t I n u v i k , NWT (68O20'N) showed t h e f o l l o w i n g r e s u l t s a f t e r t h r e e summers o f growth. P lant cover was greatest (65-85%) for Boreal creeping red fescue, Meadow f o x t a i l , A r c t a r e d creeping red fescue, and Nugget Kentucky b luegrass.

Engmo t imo thy (PhZeum pratense) and Slender wheat- grass (Agropyron trachycuuZonl produced about 50% or more cover (Hernandez 1973a). This sl ' te i s near the nor thern limit o f t h e open woodland (B lack and B l i ss 1978) .

D a t a f r o m t h e s i m u l a t e d h o t o i l p i p e l i n e s t u d y a t Fa i rbanks , A laska (64O49 'N) ind ica ted tha t Manchar brome (Brows inerws), Boreal creeping red fescue, Engmo t imothy , and Nugget Kentucky b luegrass g rew we l l and surv ived a t leas t one w i n t e r b o t h o v e r t h e h e a t e d l i n e and a t a d i s - tance o f 10-13 m f r o m t h e c e n t e r o f t h e p i p e (McCown 1973).

F e r t i l i z e r s t u d i e s a t Sans S a u l t and I n u v i k showed t h a t i n t h e s e c o l d , n u t r i e n t d e f i c i e n t s o i l s , phosphorus and n i t rogen a re most l im i t ing (Younk in 1972, 1976, Hernandez 1973a, Dabbs e t a1 . 1974). The recommended l e v e l s o f a f e r t i l i z e r mix were 112:235 kg/ha o f N and P2O5 n e a r I n u v i k and 39:79: 79 kg/ha f o r a N:P:K m i x a t Sans Sau l t (see Younkin 1976). A f o l l o w - u p f e r t i l i z a t i o n p r o g r a m t h e second o r t h i r d y e a r a p p e a r s n e c e s s a r y t o m a i n t a i n h i g h e r r a t e s o f p l a n t g r o w t h . W i t h i n t h e b o r e a l f o r e s t a species ml'x o f B o r e a l c r e e p i n g r e d fescue, F ron t ie r reed canarygrass and Sheep f e s c u e ( r a t i o 1 :1 :1 ) was recommended f o r h i g h e r o - d i b i l i t y s i t e s ( 5 6 kg/ha) and Borea l c reep ing red fescue, Meadow f o x t a i l , and F r o n t i e r r e e d c a n a r y - g r a s s ( r a t i o 1 : 2 : 2 ) f o r s i t e s o f l o w e r o d i b i l i t y (28 k g / h a ) . I n t h e f o r e s t - t u n d r a , a 2:2:1 r a t i o o f Nugget Kentucky b luegrass, Arc tared creeping red fescue and Meadow f o x t a i l (28 kg/ha) was recommended f o r h i g h and low e r o d i b i l i t y s i t e s respec t ive ly (Younk in 1976) .

Johnson (1978) has r e c e n t l y shown t h a t where a r a p i d c o v e r i s d e s i r e d t o p r e v e n t e r o s i o n , a n n u a l r ye p lan ted a lone i s best . However, i f a perenn- i a l g r a s s c o v e r i s d e s i r e d , t h e b e s t b i o m a s s was ach ieved by p lan t ing Canada b l u e j o i n t a l o n e w i t h a h i g h l e v e l o f N:P:K (228:57:114 kg/ha) rather than a m ix tu re o f A rc ta red c reep ing red f escue and b l u e j o i n t . Where annua l rye and fescue were mixed, biomass was h i g h e r t h e second y e a r f o r f e s c u e where 114 r a t h e r t h a n 228 kg/ha o f N was used. These r e s u l t s i n d i c a t e t h a t t h e s e l e c t i o n o f s p e c i e s a s w e l l a s f e r t i l i z e r l e v e l i s i m p o r t a n t i n r e v e g e t a t i o n p r o g r a m s , a t l e a s t i n t h e F a i r - banks, Alaska area.

The c o m b i n a t i o n o f r e s u l t s f r o m t h e s e s t u d i e s and the successful reseeding work by Alyeska Pipe- l i n e Co. w i t h i n t h e f o r e s t t o n e shows t h a t s o i l s can be s t a b i l i z e d and t h a t w i t h t i m e , t h e perma- f r o s t t a b l e may be s t a b i l i z e d t h r o u g h a d e t a i l e d revegetat ion program.

Low Arc t i c Tundra

P r i o r t o p e t r o l e u m e x p l o r a t i o n i n t h e A r c t i c , t he re had been 1 i t t l e i f any technology developed for r e h a b i l i t a t i o n o f d i s t u r b e d s u r f a c e s . Revege- t a t i o n s t u d i e s w e r e i n i t i a t e d a t Prudhoe Bay, Alaska (70D15'N) i n 1969 and a t T u k t o y a k t u k , N.W.T. (69'25'N) i n 1970, Sedge-moss tundra predominates a t Prudhoe Bay and low shrub-dwarf shrub heath tundra near Tuktovaktuk. Most of the species

40

Region

Table 4 . Boreal agronomic and native boreal and a rc t ic spec ies

permafrost lands, North America poten t ia l ly useful i n revegetation o f disturbed soi ls i n

Taiga closed forest

Forest-tundra

Species Agronomic Species - northern var ie t ies

Low Arctic Low s h r u b and cottongrass tundra

High Arctic Sedge-moss tundra

Cushion plant polar semi-desert

Polar Desert

Taiga fo re s t - Forest t u n d r a Low Arctic

High Arctic Tundra Polar semi-desert Polar Desert

18 species tested - Sans Saul t , NWT Durar sheep fescue Meadow foxta i l Frontier reed canarygrass Meadow fescue Boreal creeping red fescue Kentucky bluegrass Fowl bluegrass 16 species tested - Inuvik, NWl

Nugget Kentucky bluegrass Arctared creeping red fescue Meadow foxta i l Boreal creeping red fescue Engmo timothy

16 species tested - Tuktoyatuk, NWT Nugget Kentucky bluegrass Arctared creeping red fescue Boreal creeping red fescue

planted were the same as i n the northern boreal forest si tes, agronomically developed va r i e t i e s o f northern boreal grasses.

Of the 60 grass species and var ie t ies es tabl ished by ARC0 (1972) a t Prudhoe Bay, creeping red fescue seemed the most promising. Other studies a t Prud- hoe Bay by Mitchell e t a1 . (1973) and by Wein (1971) and Hernandez (1973a) i n the Mackenzie Delta region showed t h a t Arctared and Boreal creeping red fescue and Nugget Kentucky bluegrass grew well and survived the longest. Some species grew fo r one or two years, then suffered severe winter kill (red- top, Reed canarygrass, meadow f o x t a i l , Engmo timothy, Durar sheep fescue, Canada bluegrass).

A t t he c l ima t i ca l ly l e s s s eve re s i t e a t Tuktoyak-

100 species and va r i e t i e s t e s t ed

Arctared creeping red fescue Nugget Kentucky bluegrass 10 species and var ie t ies t es ted -

none none

Canada bluejoint Canada bluejoint Tal l arct icgrass

Bay Alaska

Melville Island, NWT

Native Species

- Prudhoe

. Kea P t . ,

Tall arcticgrass, dwarf hairgrass Alpine f o x t a i l , ~ h i p p s i a aZgida none

t u k , only Arctared creeping red fescue and Nugget Kentucky bluegrass showed good growth fo r t h ree summers (Hernandez 1973a). These two agronomic grasses were selected and developed by the Agricul- tural Research S ta t ion , Palmer Alaska; Nugget originated from a s e l e c t i o n a t Hope, Alaska (Hodg- son e t a l . 1971) and Arctared from the Matanuska River Valley, Alaska. For many s i t e s w i t h i n the open woodland, forest-tundra, and shrub tundras, the native grasses calmnagroutis camdensis (blue- j o i n t ) and Arctagrustis ZatifoEia ( t a l 1 a r c t i c - grass) grow well. Agronomic aspects of these two species have been studied by Klebesadel (1965, 1969) and ecological aspects by Younkin (1974). CaZmagrostis canadensis i s more common t o the northern boreal forest and Arctagrostis 2atifoZ.i.a

41

t o t h e Low Arc t i c . Bo th spec ies a re common p ioneer s p e c i e s o f s e i s m i c l i n e s and abandoned w in te r roads and w e l l s i t e s i n t h e Mackenzie Delta and uplands t o t h e e a s t (Hernandez 1973b).

Seed mixes have proven successful i n seed ing o ld w e l l . s i t e s and w in te r roads i n t he t und ra (Younk in 1976). The f i r s t seed mixes contained Nugget Kentucky b luegrass, Boreal creeping red fescue, Cl imax t imothy, Front ier reed canarygrass, and Pro- l i f i c s p r i n g r y e i n a 2 : 2 : 2 : 1 : 1 r a t i o o f 56 kg/ha (Younkin 1976), More recent mixes used Nugget Kentucky b luegrass, Arct ic creeping red fescue, and Engmo t i m o t h y i n a r a t i o o f 2:2:1 o r 2:5:2. These mixes d id no t inc lude the na t ive g rasses because o f l a c k o f seed, though i n many s i t e s t h e y began t o e s t a b l i s h t h e second year provided a l o c a l seed source was a v a i l a b l e . F e r t i l i z e r l e v e l s used by ARC0 (1972) a t Prudhoe Bay, Alaska were 56:161:165 kg/ha o f elemental N:P205:K20. M i t c h e l l and McKendrick (1975) recommended 112:66:101 kg/ha of N:P:K a t Prudhoe Bay and Younkin (1976) recommended 56:112:56 kg/ha o f N:P:K in the genera l Mackenz ie D e l t a r e g i o n . I n s i t e s o f medium t o h i g h e r o d i b i - l i t y , reseeding and r e f e r t i l i z a t i o n i n one o r two years i s recommended (Younkin 1976).

F o l l o w i n g t h e e x p e r i m e n t a l f i e l d p l o t s t u d i e s , 22 o l d w e l l s i t e s and winter roads were seeded i n 1973- 1975 f rom the outer reaches o f the Mackenzie Del ta "in low shrub tundra to open f o r e s t and f o r e s t - tundra on the Peel Plateau, ca. 320 km t o t he sou th . The r e s u l t s showed tha t seed ing on g r a v e l d r i l l pads resu l t s i n ve ry l ow g rass es tab l i shmen t (<1%) . Engmo t imo thy , t hough no t w in te r -ha rdy i n t he t und ra , prov ided 40 t o 50% o f t h e p l a n t c o v e r t h e f i r s t year. Nugget Kentucky bluegrass and Boreal creeping red fescue became wel l estab l ished the second and t h i r d y e a r ; e s p e c i a l l y when t h e l a t t e r two species were sown i n 1 : l mix. Both seed mixes and f e r t i l i z - e r can be success fu l l y sp read w i th a S l i ng -K ing seed bucket hung from a h e l i c o p t e r f l y i n g a t 48 km/ h r . Th i s seeds a t t h e r a t e o f 0.6 ha/min f o r seed and 1.25 ha/min f o r f e r t i l i z e r (Younkin 1976). The na t ive g rasses Arctagpostis Za t i fo l ia and CaZamapostis canadensis will e s t a b l i s h n a t u r a l l y where less winter-hardy species such as t imo thy a re used. The na t ive g rasses do n o t e a s i l y i n v a d e a we l l es tab l i shed cover o f b luegrass and red fescue.

The s e l e c t i o n o f a seed mix i s dependent upon t h e p a r t i c u l a r s i t e r e q u i r e m e n t s . Where e ros ion con t ro l i s needed, mixes high i n Engmo t imothy should be app l i ed . Where a s l o w e r e s t a b l i s h i n g and longer l i v e d c o v e r i s needed, Nugget Kentucky bluegrass or Arctared creeping red fescue sown s e p a r a t e l y o r 5n combination i s recommended. I f rap id es tab l i shmen t and l o n g e r l i v e d c o v e r i s d e s i r e d , the 2:2:1 mix o f b luegrass, red fescue, and t i l l o t h y i s best . I n t he b o r e a l f o r e s t t h e p r o p o r t i o n o f t i m o t h y can be i n - creased because there i s l e s s w i n t e r k i l l ( Y o u n k i n 1976).

Sh rub cu t t i ngs t es ted ove r a th ree-year per iod show a h i g h s u r v i v a l (> 95%) f o r SaZ.i:r rxlazens-is and 5 . nrhuscuZoides, 40% s u r v i v a l f o r AZnus incara and no s u r v i v a l f o r A . crfspn. These p l a n t i n g 5 a t Sans Sau l t , N.W.T. g i v e p r o m i s e f o r r e p l a n t i n g a t l eas t l im i ted a reas t o sh rub vege ta t i on (Younk in

1976). A lyeska P ipe l ine Serv ice Co. i s c u r r e n t l y t e s t i n a t h e f e a s i b i l i t y o f p l a n t i n g r o o t e d c u t t i n g s o f S a l k aLmensis on g rave l and sand bars i n nor thern A laska.

The n a t u r a l r e g r o w t h o f l o w and dwarf shrubs on s i t e s t h a t were hand or machine-c leared o f t rees and shrubs p r i o r t o c o n s t r u c t i n g t e s t s n o w - i c e w i n t e r r o a d s , a t t e s t s t o t h e f e a s i b i l i t y o f u s i n g t h i s t e c h n i q u e f o r p i p e l i n e c o n s t r u c t i o n on perma- f r o s t t e r r a i n (Adams and Hernandez 1977, Younkin and Het t inger 1978) . The r e g r o w t h o f sedges, grasses, and low shrubs on the w in te r snow- ice roads used f o r s e v e r a l y e a r s i n t h e sedge-moss, cot tongrass tussock and low shrub tundras northeast o f I n u v i k , NWT a l s o shows t h e p o t e n t i a l f o r n a t u r a l recovery (Campbell and 61 iss -unpub l i shed da ta) . I n these areas the 10-15 cm pea t l aye r p rov ides c o n s i d e r a b l e i n s u l a t i o n w i t h t h e r e s u l t t h a t permafrost me1 t seldom occurs, provided vehicles do n o t s t a r t snow r o a d c o n s t r u c t i o n t o o e a r l y i n t h e w i n t e r n o r o p e r a t e t o o l a t e i n s p r i n g when t h e sur face begins to thaw.

There i s a c o n s i d e r a b l e b o d y o f l i t e r a t u r e on the genera l impact o f indus t r ia l deve lopment in the Soviet North (Brown and Grave - t h i s volume, Andrews 1977, 1978). However, few o f these papers g ive d e t a i l e d i n f o r m a t i o n on res to ra t i on p rocedures beinp used. Andreev (1979) has o u t l i n e d i n g e n e r a l terms the l i t e r a t u r e on t h e i n f l u e n c e o f human f a c t o r s , i n c l u d i n g t h e i m p a c t o f r e i n d e e r g r a z i n a , on tundra veaetat ion. Revegetat ion on go ld m in ing spo i l s requ i res 8 -10 yea rs and graminoids become e s t a b l i s h e d i n v e h i c l e t r a c k s i n 3-4 years. Weedy species have increased i n t h e N o r t h due t o l a n d c l e a r i n g and i n c r e a s e d t r a n s p o r t a t i o n r o u t e s (Dorogostaiskaya 1972). She repo r ted 298 weedy species o f d is turbed so i ls around towns, a long ra i lways , and m i n i n g s i t e s from a r c t i c and sub- a r c t i c l a n d s . O f these, 2 spec ies are in t roduced weeds o f a g r i c u l t u r a l l a n d s and 42 species have t h e p o t e n t i a l f o r s p r e a d i n g more w i d e l y as human a c t i v i t y i n c r e a s e s . I n t h e w e s t e r n T a i m y r Pen insu la a t the se t t lement o f Kres ty , Matveyeva (1978) has descr ibed nat ive spec ies that invade d i s t u r b e d s o i l s . O f t h e l o c a l f l o r a (-. 200 species) o f v a s c u l a r p l a n t s , 89 species occupy disturbed hab i ta ts . Yur tsev and Korobkov (1978) l i s t species o c c u p y i n g d i s t u r b e d s o i l s n e a r t h e v i l l a g e of Yanrakynnot on the Chukotka Peninsula.

The r e s u l t s o f t hese va r ious s tud ies , i nc lud ing t h e u n i f o r m i t y o f r e s u l t s u s i n g n a t i v e w i l d and northern aaronomic species, show tha t cons ide rab le success i n s t a b i l i z i n g s o i l can be achieved under a r c t i c c o n d i t i o n s ( T a b l e 4 ) . L imited success i n r e s e e d i n g t h e a r c t i c p o r t i o n o f -the Alyeska Pipe- l i n e has occurred, though a program o f reseedina and r e f e r t i l i z i n g f o r a number o f y e a r s i s p r o b a b l y necessary.

High Arct ic Polar Semi-Deser ts

More than 50 w e l l s have been d r i l l e d i n t h e Western Canadian A r c t i c A r c h i p e l a g a . I n r e l a t i o n to we l l c l ean -up ope ra t i ons and p re l im ina ry p lans f o r a gas p i p e l i n e on M e l v i l l e I s l a n d , a l i m i t e d revegetat ion program was i n i t i a t e d . Three s i t e s

42

were estab l ished on M e l v i l l e I s l a n d and one on E l l e f R ingnes I s land . A f te r f i ve yea rs o f wo rk t he main conclusions are: 1) none o f t h e 10 agronomic spec ies tes ted surv ived over w in te r ; 2 ) hydro- seeding was more successful than broadcast seeding; and 3 ) f e r t i l i z e r ( r a t i o 1 : 4 : 4 ) a p p l i e d a t t h e r a t e o f 245 kg/ha st imulated growth o f na t ive spec ies as we l l as the agronomic species under test ( M c G i l l i v r a y 1976). These s t u d i e s v i v i d l y demon- s t r a t e t h e f u t i l i t y o f p l a n t i n g b o r e a l f o r e s t spec ies we l l beyond the i r c l imat ic limit.

I n a separate study, CuLmagrostCs canadmsis and nrctagrostis ZatifoLia n a t i v e t o t h e T u k t o y a k - t u k and Inuv i k a reas were p lan ted a t t he T rue love Lowland, Devon I s l a n d (75'N) and on K i n g C h r i s t i a n I s l a n d (78'N). There was l i m i t e d seed germinat ion and p l a n t e s t a b l i s h m e n t f o r a t l e a s t f o u r years on the Truelove Lowland. Survival was much g r e a t e r i n AretagrostLe. A t t h e more severe s i t e w i t h i t s shor te r g rowing season on K i n g C h r i s t i a n I s l a n d , o n l y a few seeds germinated and no plants survived o v e r w i n t e r ( B l i s s and B e l l - unpubl ished data). A t t h e l a t t e r s i t e Phippsiu aZgidia and Alopecums aZpinus seeded i n n a t u r a l l y i n t h e f e r t i l i z e d p l o t s , i n d i c a t i n g a g a i n t h e p r a c t i c a l i t y o f u s i n g nat ive species rather than agronomic races o f s p e c i e s p h y s i o l o g i c a l l y a d a p t e d t o d i f f e r e n t environments.

Unless there are major breakthroughs in our knowledge o f h i g h a r c t i c s p e c i e s , t h e r e seems l i t t l e o r no hope o f r e v e g e t a t i n g t h e t r u e p o l a r dese r t s . The shortness of season, low sol1 temp- e ra tu res , and d r y s u r f a c e s o i l s seem to negate success. Only very l imited success appears p o s s i b l e i n r e v e g e t a t i o n work i n t h e n o r t h e r p o l a r semi-deserts (Table 4 ) .

Summary

The d a t a a v a i l a b l e i n d i c a t e t h a t n o r t h e r n r a c e s o f agronomic species are well adapted f o r use i n r e - vegeta t ing nor thern borea l fo res t lands . A few of these species and two grasses nat ive to the nor th- e r n f o r e s t s and tundra have been used with reasonable success i n t h e Low A r c t i c . Few s tud ies have been done t o d a t e on r e v e g e t a t i o n i n t h e H i g h A r c t i c , b u t t h e l i m i t e d r e s u l t s show l i t t l e promise f o r r e s e e d i n g s u r f a c e d i s t u r b e d s o i l s . All s o i l s a r e n u t r i e n t d e f i c i e n t and r e q u i r e h i g h a p p l i c a - t i o n s o f n i t r o g e n and phosphorus (100-200 kg/ha). There are examples o f s u c c e s s f u l r e v e g e t a t i o n i n these nor thern permaf ros t lands , bu t those nor th of 72' ho ld less p romise f o r s o i l s t a b i l i z a t i o n through seeding programs.

ACKNOWLEDGMENTS

The f inanc ia l suppor t o f the Nat iona l Research Counc i l o f Canada, t h e A r c t i c Land Use Research Program, and member companies o f t h e A r c t i c P e t r o - leum Operators Associat ion, and t h e l o g i s t i c s u p p o r t o f t h e P o l a r C o n t i n e n t a l S h e l f P r o j e c t a r e g r a t e f u l l y acknowledged. Without the f inancial suppor t o f these agencies to the author and t o o ther nor thern researchers and comparable agencies i n t h e U n i t e d S t a t e s and the Sov ie t Un ion , our knowledge of these nor thern lands would be min imal .

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POSPELOVA, E.B. 1972. Vegeta t ion of t h e Agapa s t a - t i o n a n d p r o d u c t i v i t y o f t h e m a i n p l a n t communi- t i e s . I n : Proceed ings IV. I n t e r n a t i o n a l M e e t - i n g o n t h e B i o l o g i c a l P r o d u c t i v i t y o f T u n d r a . (F.E. W i e l g o l o s k i a n d T. Rosswal l Eds. ) . Tundra Biome Steer ina Commit tee. Stockholm. 320 p .

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157-184.

45

RITCHIE, J.C. 1959. The v e g e t a t i o n o f n o r t h e r n Manitoba 111. S t u d i e s i n t h e s u b a r c t i c . A r c t i c I n s t . N . A . Tech. Pap. 3, pp. 1-56.

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ZOLTAI,S.C. 1972. Palsas and peat plateaus in

28-43.

F I G U R E CAPTIONS

Fig. 1. Permafrost distribution based on recent revisions by T.L. ~ B w e ' and the boundaries of the Low and High Arctic.

Fig. 2. Pattern of forest, fen, and mountain tundra in r e l a t ion to topography, s o i l s , and depth of the active layer, Norman Wells, NWT, Canada *

46

Fig. 3. Pattern of forest and iundra wit1 in the lichen-woodland open forest near Inuvik, NWT, Canada.

Fig. 4 . Idealized pattern o f low arct ic tundra communities in relation to topography, soils, and depth of the active layer in the Foot- hill province of the North Slope Alaska.

Fig. 5 . Pattern of dwarf shrub and sedge moss tundra communities and cushion plant communities o f man polar semi-desert a r e a s , Truelov Lowland, Devon Island, Canada.

Fig. 6. Pattern of moss-herb communities and limited areas of dwarf shrub heath and sedge-moss tundra, wit; in a polar semi-desert landscape Rea Pt. , Melville Island, NWT, Canada.

Fig. 7 . Limi ted pattern of "plant communities" in relation to soil: active layer , and topography witk in the p o l a r desert landscape, ne Resolute, Cornwallis Island, NWT, Canada.

47

180"

.r permafrost zone

2000 km '.,-, "" 1% . L" ,, '. \ 1. ,/ \

90"

Figure 1

48

?" Low Shrub and Cushion Plant tundra

Soils well drained - Regosols.

Active layer 7 5 - 1 5 0 c m

-" -- 1 " White Spruce - pH 6 . 7

Sedge-Moss Fen

Soils poorly Black Spruce. dralned . Balsam Poplar Open Forest Flbrtsols. Closed Forest pH 5 - 6.5 Soils imperfectly Actlve layer Soils imperfectly drained - 40.60 cm drained - Gleysols to

Gleysols. Fibrisols.

White and Black Spruce Soils well drained. Regosols to Brunisols, pH 5 . 6.5 Active layer 100 - 150 cm

pH 6.5 . 7.5 Active layer 75. 150 cm

pH 5 - 6.5 Active layer 40 - 60 cm

Figure 2

Blrch-Moss Open For@st

Soils well to imperfectly Whlte Spruce - drained. Sedge-Moss Open Fore8t Brunisols to Fen

Balsam Poplar

Regosols. ' Closed Forest

Actwe layer drainsd -

Soils poorly to

drained - pH 5 - 6.5 Soils poorly Soils well to imperfectly

80. 100 cm Fibrisols. pH 5 - 6.5 imperfectly dralned ~

Gleysols to Regosols. pH 5 - 6.5 Active layer 40 - BO cm

Active layer Brunisols, pH 5 - 6.5 40.70 cm Active layer

50 - 100 cm

Low Shrub and Cushion Plant Tundra

Soils well drained - Brunisols. p H 6 - 7 Active layer 50 ~ 100 cm

Regosois to

F i g u r e 3

49

r , - - - =

Cushion Plant. Moss/Lichen

Winter snow 1 0 - 2 0 c m Soils well drained.

Brunisols. Regosols to

Active layer 50 - 70 cm

pH 5 - 6.5

Cottongrass

Dwarf Shrub TUSSOCk - Heath-Moss

Winter snow 30 - 60 cm Soils imperfectly drained. Gleysols.

Active layer 40- 50 cm

PH 5 . 6.5

Figure 4

".

Tall Shrub Tundra

Winter snow 2 - 3 m Soils imperfectly

GIeysols. drained -

pH 5 - 6.5 Active layer 40- 60 cm

Wet Sedge Tundra

Wlnter snow 50-100m Soils poorly drained. Fibrisols, pH 4 - 5.5 Active layer 25.35 cm

Cottongrass

h a r t Shrub Heath-Moas

Winter snow 30 - 60 cm

drained - Soils imperfectly

Gleysols. pH 5 . 8.5 Active layer 40 - 50 cm

TuSJock -

h a r l Shrub neath Cushion Plant

Lichen Frost-Boil

40 - 150 cm Winter snow Sedge-Moss Hummocky

Wlnfer snow Tundra Soils well to

Sedge-Moss Cushion Plant 1 0 - 2 0 c m

imperfectly Soils well Wlnter snow Tundra

drained drained Regosols to Brunisols. pH 7 - 8 Active layer 35 - 40 cm

Lichen

Wmter snow Sedge-Moss Hummocky 1 0 - 2 0 c m Wlnter snow Tundra

Cushion Plant

30.50 cm Wlnter snow Moss

dralned So~ls poorly Soils well Sedge-Moss

Frost-Boll

Regosols. Soils poorly 30 - 50 cm

Actwe layer Gleysols, dramed drained 80 - 100 cm pH 6.5 . 7.5 Gleysols to

pH 7 - 8 5 0 - 1 5 0 c m Soils well to Winter snow

Active layer Fibrlsols, Regosols. imclerfectb 30 - 50 cm Winter snow

45 . 55 cm pH 6.5 - 7.5 Active layer Bruntsols. drained drained Soils Poorly 30. 50 cm

Active layer 80 - 100 Cm pH 7 . 8 Soils poorly 25.35 cm Gleysols, drained

Tundra

pH 7 - 8

Actwe layer PH 6.5 . 7.5 Gleysols to 4o - 70 cm Active layer Flbrlsols, 4 5 . 5 5 cm pH 6.5 - 7 5

Figure 5

50

1 - MOSS-Herb

War t Sh rub Winter snow Heath

Winter snow 50 -100cm Winter snow Soils imperfectly 20 30 cm drained ~ Soils poorly Regosols to drained - GIeysoIs. Gleysols lo

Active layer pH 5.5 . 7 30.50 cm Active layer

25.35 cm

Tundra Sedge*Moss 1 0 - 2 0 c m

Soils imperfectly drained - Gleysols. pH 6 ~ 7.5 Active layer 30 - 50 cm

p l l 6 - 7.5 Fibrisols,

Figure 6

Winter snow 5 - 1 0 c m Solls well drained - Regosols.

Active layer 25 - 40 cm

pH 6. 7.5

Snowbank .,

Snowflush Moss-Herb

Winter snow 50 - 150 cm Soils Imperfectly drained - Gleysols. Regosols to

pH 5 . 5 . 7.0 Active layer 25 - 40 cm

Barrens

Winter snow

Soils well 1 0 - 2 0 c m

drained . Regosols, pH 6 - 7.5 Active layer 25 40 cm

Figure 7

PHYSICAL AND THERMAL DISTURBANCE AND PROTECTION OF PERMAFROST*

J. Brown' and N.A. Crave'

' U . S . Army Cold Regions Research and Engineering Laboratory Hanover, New Hamp.shire, USA

'Permafrost Institute, Siberian Branch, Academy of Sciences of I ~ P USSR, Yaku tsk , USSR

INTRODUCTION

Since 1973 the trans-Alaska pipeline has been constructed, the limits of subsea perrnafrost in the Beaulort Sea have been investigated, the route has been selected for a large-diameter natural gas line running south from northern Alaska, construction of the Baikal-Amur Railroad (HAM) has progressed, and exploration for oil, gas, coal and other resources has continued throughout the mid- and high-latitude circumpolar regions. Those who have undertaken these massive construction and planning projects have considered many of the environmental impacts and harards associated with permafrost and the problems involved in protecting and restoring the terrain (for instance Berger l977a, b, Eddy 1974, Lysyk 1977, Mel'nikov 1976, National Energy Board 1977, Weller and Norton 1977).

Disturbance of the terrain, whether by natural or artificial causes, is bound to result in an acceleration of natural processes (Jahn 1976). Most factors that tend to disturb the natural environmental equilibrium are assoc ia ted w i th human ac t i v i t y . Hut na tura l catastrophes occur as well: torrential rainfall, earthquakes, and fires. Terrain disturbance tends to increase the mean annual surface temperature. The active layer may become thicker and the thickness of the permafrost may decrease. The increase in thaw rnay be a few centimeters and be of little practical consequence, or we rnay observe gully formation, thermokarst development, landslides, and other forms of mass wasting. The magnitude of the disturbance depends mostly on the amount and type of buried ground ice, its proxitnity to the surface, the sediment type, and the time since disturbance.

This paper reviews the major findings of site and regional investigations dealing with human-induced and natural disturbances. Since the review paper by Bliss in

this volume discusses the distribution and characteristics of arctic and subarctic vegetation, its relationship to permafrost, and natural and artificial revegetation, this review deals extensively with the physical and thermal aspects of terrain disturbance. A recently publlshPd paper by Webber and Ivcs (1978) discusses many aspects of tundra damage and recovery. It has not bcen possible to reference or discuss all available literature. In general, the references cited were published since 1974, although there are some earlier citations where considered pertinent.

Closely associated with terrain disturbance are subjects related to ground temperature regimes. Cold and I x h e n b r u c h (1973) presented a major review on thermal conditions in the permafrost of North America. An up- date on ground temperature literature, mainly from North America, and associated microclimatic, energy cx- change, and computer modeling studies are summarized in Appendix I . Microcl imatic studies were an integral part of the investigations at the International Blological Program Tundra Biome sites at Harrow (Alaska), I.levon Island (Canada), Niwot Kidge (Colorado) and several Scandinavian countries (Rosswall and Heal 1975). These studies, and the interest in modeling thermal processes associated with heated oil pipelines and proposed refrigerated gas pipelines and embankments, gave rise to many publications on computer modeling of soil thermal regimes and coupled heat and mass transfer processes (see, for instance, American Geophysical Union 1975, 197h). Specific aspects of the Soviet literature on ground thermal regime are presented in the text.

The first half of this report deals with literature from North American and other circumpolar regions, ex- cluding the Soviet Union. The second half of the report contains the discussion of the Soviet literature.

5 2

REGIONAL STUDIES, MAPPING AND TERRAIN SENSITIVITY IN NORTH AMERICA

Environmental assessments and design considerations associated with large regional projects such as oil and gas pipelines have resulted in several major programs t o study their potential impact upon permafrost. In Canada these efforts were accompanied by government-and industry-sponsored terrain and ecological investigations of the Mackenzie Valley and the Arctic Islands. The Mackenzie investigations began in the early 1970's and during the period of this survey a large numbcr of government reports have been published in several series (reports of the Task Force on Northern Oil Development, Arctic I.and Use Kesearch (A.L.UK.) and the t nv i ronmen ta l S tud ies Series). In Alaska, preconstruction terrain mapping along the trans-Alaska pipeline was undertaken by industry (Kreig 1977). The Prudhoe Bay oil field provided an opportunity for developing a mapping scheme for evaluating various types of impacts (Everett et ai. 1978).

Strang's (1973) study on the effects of disturbance at a wide range of sites in the Macken7ie Valley differen- tiated between rwn-damaging and detrimental changes. Change W A S deemed darnaging if its effect extended beyond the area of initial impact. A change in floristic composition, a shallow depression, or a slight lowering of the permafrost table was rated not damaging. Ac- celerated bank erosion, siltation of a stream bed, and other outward spreading of a disturbance were considered harmful. Surface disturbance increased the average active layer thickness in the Mackenrie Plain by 23 cm, in the Peel Plateau by 21 cm, and in the O l d Crow area b y 10 ctn. Causes of serious damage were the exposure of subsurface frozen soil on sloping ground (>5%), the intersection and diversion of drainage channels, travel on unfrozen wet ground, and the reuse of old roads or seismic lines. Several conclusicms from these observations are: 1) sites underlain by ice-rich strata close to the surface are most vulnerable to disturhance, 2) any activity which modifies or destroys the organic layer causes some degree of damage, 3) sites undergoing recoloniLation are vulnerable to further disturbance, and 4) i t i s during the thaw season that the surface is most susceptible to disturbance.

A series of reports and maps describe the surficial deposits and landforms in the Mackenzie Transportation Corridor, They include rankings of the susceptibility of various terrain units to thermokarst, slope failure, gully erosion and other hazards (Hughes et al. 1973, Rarnpton 1974, Rutter et al. 1973, Zoltai and Pettapiece 1973). The distribution of terrain hazards related to thermokarst gullying and slope failure is controlled by the occurrence of high ice materials and massive ice beds. The hydraulic and thermal erosion resulting from the concentration of drainage along or adjacent to pipelines

and roads constitutes a major hazard. The till plains af- ford the best potential routing and the glacio-lacustrine plains the most difficult, hecause of potential thermokarst conditions and highly unstable slopes. Slope failures are attributed to the thawing of frozen sediments, either due to thickening of the active layer or the undercutting of a slope. In the southern portion of the Mackenzie Corridor, areas of thick organic matter consisting o f unfrozen fenland and ice-rich bogland pose the most significant problems in pipeline construction.

Kurfurst (1973) prepared preliminary terrain sensitivity maps of the Norman Wells area based on observations of terrain response to natural and human-induced disturbances. These included fire and removal of trees, surface vegetation and soils. Many of these activities were associated with exploration and drilling. t ie emphasized that the susceptibility of the terrain to disturbance is controlled by ground ice or moisture content, material type, slope, and relief. Bedrock, sands and gravels are least susceptible, till and organic sediments moderately susceptihle, and clay and clayey silts most susceptible.

The results of many of these Mackenzie Valley investigations have been compiled and synthesized into two terrain sensitivity maps (1:l,OOO,OOO) in a report of the Environmental-Social Committee on Northern Pipe- lines (1975). The maps show surficial deposits, ecoregion, terrain sensitivity, disturbance level, and t.ype of reac- tion, An ecoregion consists of land characterized by a distinctive regional climate. Terrain sensitivity was divided into seven classes based on the degree of reac- tion to terrain disturbance, and is dependent on ground ice, slope, material, and insulating cover. The mapped sensitivity ratings are indicative of maximum deteriora- t ion response. The presence or absence of permafrost and the type of ground are the two most important factors, Based on soil data from over 11,600 bore holes in the Mackenzie Valley, Heginbottom et al. (1978) concluded that the major factors controlling permafrost conditions were location (latitude) and soil texture.

An interdisciplinary mapping scheme for terrain characterization and evaluation was developed by Barnett et al. (1977) and illustrated for eastern Melville Island. The map scale is 1:250,000 and data are presented on a photomosaic base at three levels of detail: I ) landscape type (regional), 2) geobotanical facies (intermediate), and 3) terrain units (local). The subdivision into terrain units is based on criteria such as soil moisture, surface material, plant community, degree of dissection, and slope. The mapping scheme evaluates ground ice and engineering properties, trafficability, and sensitivity to. overland travel and trenching. The approach provides a mechanism for combining natural subdivisions of the landscape (ecological, geological,

53

pedological) on a single, map and considers surface materials as a key element of potential disturbance. Units are rated for sensitivity to several types of impacts.

Babb and Bliss (1974b) prepared a provisional map of the Queen Elizabeth Islands which emphasized the susceptibility of soils and vegetation t o surface disturbance. Four broad categories were mapped: 1) Polar desert (31 % of the land area), 2 ) Polar semi-desert (25%), 3) Diverse terrain (22%), and 4) Large meadows (<Z%). Precautions or limitations for activities in each unit were presented. Although the Barnett et al. (1975, 1977) and Babb and Bliss (1974b) approaches differ considerably, both present useful information to planners when initial decisions are required for terrain utilization.

A more detailed approach to terrain sensitivity mapping has evolved at Prudhoe Bay which integrates soil and vegetation with respect to landform units at a scale of 1:6000 (Everett e t al. 1978, Webber and Walker 1975). Ten landform units, s ix soil units and thirteen vegetation units are recognized. Soils and vegctation are displayed within the same landform boundaries and the result is referred to as a master map. Master maps provide the basis for generalization or for preparing very specializcd interpretations. Depending upon the w m ' s need, information may be extracted to form a derived map, for instance a map reflecting the thickness of the peat layer or the active layer for use in oil spill clean-ups. The most complex derived map is used to evaluate terrain sensitivity. A scheme for rating the impact of off-road, low pressure balloon-tired vehicles on vegetation was developed which described the type of disturbance and estimated the immediate and long-term impact (Walker et al. 1977). Oil spill sensitivity maps are being field- evaluated in conjunction with controlled and uncon- trolled spills (Walker et al. 1978). Follow-up reports will evaluate the accuracy of the technique, and a terrain atlas of the Prudhoe Bay region is heing prepared at CRREL by the same authors.

Terrain or landform analyses were an integral part of the design and construction of the tramAlaska pipeline. Kreig (1977) and Kreig and Reger (1976) described the terrain unit tnap approach utilized in assessing the occurrence of thaw-unstable permafrost for purposes of locating material sources and evaluating slope stability conditions, and for other design requirements. The maps were prepared on a photomosaic base at a scale of 1:12,000 to show the landforms expected In a 3.5- kilometer-wide strip along the proposed oil pipeline route. Soil data from 3.500 borcholes and numprous field observations were utilized. A 15-rn depth profile was prepared of the geotechnical conditions anticipated along the pipeline centerline. An impc.)rtant contribution of the TAPS landform approach was the computeri7ed data bank of soil and terrain conditions that was developed.

Several relationships governing the distribution of permafrost and the thickness of the active layer were evaluated by Dingman and Kout7 (1974) in a smal l drainage area (1.8 km2) in interior Alaska. A solar radiation index, based on the concept of equivalent latitude

and a function of slope and aspect, was shown to be closely related to vegetation and permafrost distribution. The boundary of permafrost in this region of discontinuous permafrost appears to coincide with an isopleth of 365 calories/cm2-day. The thickness of the active layer correlated significantly with the solar radiation index, Vegetation characteristics appeared to be at least as important in controlling active layer thickness. Also, in interior Alaska, Haugen and Brown (1978) indicated that the lower and cooler tundra-covered slope below timberline also favored the development of cold permafrost. This was associated with fine-grained soils and a shallow active layer (<60 cm as compared to >I m on the upper slopes).

Several other permafrost-related mapping activities were also published. Sellmann et al. (1975), employing Landsat satellite imagery as an aid, developed a classification scheme for the thaw lakes of the Alaskan Arctic Coastal Plain that refined previous descriptions for these oriented lakes. It consists of six lake units and three non-lake units based on size, development of orientation of the elongated axis, lake density (percent water coverage), and controlling pararncters such as regional or local relief and structural control. Methods were also discussed for estimating depth of water and potential maximum depth of thaw settlement and refine- ment of the transgressive history of the region. Using Landsat data, Tarnocai and Kristof (1970) developed a computer-aided classification and map of the terrestrial and aquatic environments on Richards Island, Candda. Spectral data wcrc grouped into 14 terrestrial and 8 aquatic classcs. Lathram (1974) was able to identify vehicular scars at Umiat, Alaska, using enlargements (1:80,000) of Landsat imagery. These tracks, which resulted from drilling activities in the period 1945 to 1952, were examined in the field in 1973. Well- developcd beaded streams have formed on the ice-rich lowlands.

NATURAL PROCESSES

The development of natural thermokarst features has been summarized by Brown (197.3) and Hatnplon (1973). Rampton concluded that thermokarst processes are sti l l active in the Mackenzie-Beaufort region, but have slowed down, possibly reflecting a deteriorating climate in the area over the past 5000 ycars.

French (1974) described activc thermokarst processes in eastern Banks Island. Broad and shallow ground ice slumps with a regional density of 0.5/kmz are retreating at 6.0 to 8.0 tn/yr. I t is estimated that the \lumps become stabillzed within 30-50 summers. In the same area, thcr- mal melting and erosion along ice wedges are resulting in the development of badland terrain (haydzhurakh). Since the climate is probably not undergoing an unusual general warming, it was concluded that the active thrr- mokarst is the result of local, nonclimatic factors.

Mackay (1078) measured radiant surface temperature data for thawing headwalls in ice-rich permafrost on

54

Gary Island. Headwall retreat had been active from 1963 to 1971 at a rate of 6 m/yr. All temperatures on the thawing headwall were above O°C under bright sunshine. Sur- face temperatures increased rapidly as muddy water flowed downslope, rising 5 O to 1OoC in less than one minute.

Thie (1974), using aerial photography acquired over a 20-year period, measured the degradation of permafrost in the southern part of the discontinuous permafrost zone in Manitoba. The observations were based on peripheral and central collapse in palsas and peat plateaus. Retreat due to edge collapse was as much as 20 m. Up to 60% of the land portion of this area once contained permafrost; now only 15% does. This degradation apparently has been active over the past several centuries.

Priesnitz and Schunke (1978) reported on the permafrost of central Iceland, where both degradation and aggradation processes are or have been active. The permafrost i s up to 6 m thick. ‘Thermokarst depressions, valleys and mounds are described as degradation forms. Over 1200 palsas have been mapped and are considered to be indicators of aggrading permafrost.

Ugolini (1975) described an unusual form of therrnokarst along the Noatak River Delta in Alaska. t i e suggested that upon melting, ice-rafted sediments deposited a layer of mud on the permafrost terrain, which in turn resulted in increased thawing, subsidence and subsequent pond formation.

The quickest way to measure thaw i s to force a small- diameter rod into the s o i l to the point of refusal. However, these determinations of thaw depth are subject to error. Mackay (1977a), using a temperature probe and metal probes of varying diameters, evaluated the results obtained this way under different s o i l and ice conditions on the 1 uktoyaktuk Peninsula. Firm resis- tanre to probing corresponded to the O°C isotherm in icy, organic soils, ice-bonded coarse-grained soils, and ice-lensed fine-grained soils. But in fine-graincd soils free of ice lenses, probes could usually be pushed beyond the O°C frost table. The large unfrozen pore wdter content of silty clay and clay soils can lead to overestimates of several decimeters in the depth of the frost table. In such soils, larger diameter probes may give a better physical estimate of the O°C isotherm.

The depth of thaw along the coast of northt.rn Alaska has’ been investigated at several sites, e.g. F’eard Bay (Harper et a l . 1978, Owens and Harper 1977) and Vingok Island (Fisher 1977). Thaw measurements along four profiles across a 55-m-wide barrier pit and a beach backed by a tundra bluff revealed that the spit exporienced the greater thaw. In the gravel of the spit the rate of thaw increased during late summer, with 0.6 to 0.7 cmiday heing measured as opposed to the more usua l rates of 0.2 to 0.4 cm/day in soils. This greater rate was attributed t o the nesrshore water with its higher heat capacity and salinity. Total mean seasonal thaw ranged from 03 to 131 cm across the four profiles.

In a related detailed investigation of thaw depths on Pingok Island in the Beaufort Sea o f f Alaska, the normal

exponential seasonal decrease in thaw was noted (Fisher 1977). Here the base of the active layer generally conformed to surface polygon configuration. An inversion of surface topography developed beneath hummocks and over the ice wedges that were close to the surface. Slope exposure was found to affect the thickness of the active layer significantly, whereas moisture content and sediment size had only minor effects. The southwest slopes had thicker active layers than the southeast slopes, which were about the same as the north-facing slopes. The vegetation cover was the dominant factor in inf luencing the thickness of the act ive layer; unvegetated sites had over 100 cm of thaw, while vegetated areas had 30-60 cm.

Brown et al. (1975) presented thaw data for major soil conditions at Prudhoe Bay: <30 cm for dry organic soils, 40 cm for silty dry meadow tundra, 60 cm for sandy dry meadow tundra, and >90 cm for sandy upland tundra. From the same area, Walker and Webber (1979) reported thaw increases as a function of distance from the cold bay: 22 cm near the bay and 3 3 cm inland. A strong summer air temperature gradient exists from the shore of the Arctic Ocean inland several tens of kilometers (pers. comm., R.K. Haugen, CRRfL).

Peterson and Billings (1978) investigated the interaction of vegetation patterns and geomorphic processes along sandy hluffs in northern Alaska. Maximum depth of thaw occurs near the edges of the bluffs and exceeds 100 cm. Within 5 0 m of the edge, values decrease to less than 40 em. The sand deposits were observed to be stabilized by the presence of the permafrost table, which rises as vegetational cover increases.

Nicholson and Lewis (1976) investigated the deeper thaw (10-12 m) under drainage lines in Schefferville, Quebec. Normal active layer thicknesses in the region range from 2.4 m under continuous vegetation to X6 rn under bare ground. Nicholson (1Y78b) indicated that permafrost i s actively developing in mine waste dumps (8-10 111 in 10 years) a t Schefferville and that areas deforested by fire and having shallow snow cover may develop 10-20 m of permafrost over a 25-30 year period of revegetation.

Hannell(1973) correlated depth of thaw with the l-cm- deep daily temperature. The emphasis was on slopes of approximately 30° on the southwest coast of Devon Island. Contrary t o accepted principle, active layers on north-facing slopes were consistently 5-10 cm thicker (20-40 cm on the south-facing slopes and 25-45 cm on the north-facing slopes). Active layer thickness increased as the slope of the surface declined, with 52-cm depth found on an 18O slope as opposed to 40-47 cm on a 2 9 O

Ponds and lakes on the Colville Delta, northern Alaska, are dynamic features of that landscape. Walker and Harris (197h) described perched intradunp ponds with depths of up to 1.3 m. The restricted thawing of the active layer insures maintenance of the pond level above the regional ”water table” throughout the summer. Total thaw beneath the pond i s only about 60% of that beneath the exposed sand dunes. Maximum depth

slope.

55

of thaw in the ponds is about 110 cm. These ponds are relatively short-lived as either filling by the blowing sand or drainage by headward erosion leads to their extinc- tion. Walker (1978) describes the process of lake tapping. As the lake enlarges and the river erodes lakeward, thawing of ice wedges creates channels through which the river can overflow. Further erosion results in partial or complete draining of the lake. Other papers on the Alaskan lakes discussed the role of lineament control in lake orientation (Short and Wright 1974) and compared the origin of the Carolina Bays with the Alaskan oriented lakes (Kaczorowski 1977).

Erosion of permafrost along river banks and shorelines is a natural form of terrain disturbance. Cooper and Hollingshead (1973) reported on several cases of bank erosion in the Yukon Territory and emphasized that the active layer annually provides an easily erodable and unstable slope material. Newbury et al. (1978) concluded that shoreline erosion in reservoirs on permafrost occurs through a combination of thermal and mechanical processes that cause a deep niche to form immediately below the waterline, which then leads t o slumping. Ri t - chie and Walker (1974) identified nine forms of river

as an increase in active layer thickness, settlement, and compaction, and 3 ) ecological impact and ability to recover. How (1974), in an assessment of the effects of the proposed gas pipeline construction on the terrain found in the Mackenzie Valley, summarired the major causes of human-induced impacts and the mechanism and consequences of each (Table 1). Brown et ai. (1978) discussed the following causes of tundra disturbance, many of which are found in the western U.S.: grazing, recreation, mining, roads, pipelines, powerlines and reservoirs.

Heginbottom (1973, 1974-75) discussed three main causes of disturbance as being related to human set- tlements, forest fires, and oil and gas exploration activities. Where bulldozers cleared trails in summer by simply pushing over trees and leaving the forest mat in place, thaw conditions under it and the adjacent undisturbed sites remained essentially the same. When the vegetation mat was pushed aside, deep thaw and slumping occurred. Surface disturbance results in compaction of the surface soil, which in turn alters the soil thermal properties, while removal of the surface alters the albedo. The downward flux of heat in summer increases

banks along the Colville River, four of which were ero- following physical disturbance, causing warming of the sional, four depositional, and one neutral. Thermal ero- permafrost and deeper thawing. Subsidence occurs as sion and thawing result in the development of niches excess ice melts and water drains. On sloping terrain, along the bases of the banks. Bank collapse and block slope failures, mass movement and landslides occur, sloping are common. Harper (1978) indicated that the Coarse-grained soils are more resistant t o these forms of average rate of coastline retreat between Peard Bay and disturbance. Barrow, Alaska, is 0.31 m/yr. Code (1973) mapped the The following sections discuss the response of per- stability of river banks along the Mackenzie River and i t s mafrost terrain to a variety of human activities. Fire tributaries. disturbance, although generally considered a natural

In several papers, McRoberts and Morgenstern (1974a, phenomenon, is included in this discussion primarily b) emphasized the important role thawing plays in a because it is frequently compared with other forms of wide range of landslide types associated with per- human-induced disturbances. mafrost. The most common landslides of thawed materials are flow-dominated and are subdivided into Off-road transportation solifluction, skin flows and bimodal flows. Slope failures In the absence of established roads, surface transpor- on frozen soils were classified and analyzed as block tation is . now restricted to environmentally non- and multiple retrogressive. destructive modes. In winter this i s accomplished using

Zoltai et al. (1978) sampled a large number of earth over-snow tracked vehicles or, on snow and ice roads, by hummocks from the Canadian Arctic and reported more conventional wheeled vehicles. In summer, ex- radiocarbon dates from the buried peats and organics. perimental machines such as low pressure balloon-tired Most of the samples were 3000 to 4000 years old. These vehicles (Rolligons) and air cushion vehicles (ACVs) are dates correspond to a climatic change toward colder being used. Rickard and Brown (1974) reviewed much of and moister conditions about 4500 years ago, conditions the available literature on summer off-road vehicular which presumably would favor an intensification of impact. The U.S. Bureau of Land Management sponsors frost action and peat burial. and publishes surface protection seminars (Evans 1976,

HUMAN-INDUCED DISTURBANCES

1977) at which numerous individual reports are presented on problems and their solutions associated with off-road impact, transportation, and protection of the terrain. A number of experimental investigations

Human activities which initiate disturbance can be have been undertaken to observe the performance and divided into 1) point activities and 2 ) extensive activities potential impact of both summer and winter vehicles. (Barnett et al. 1975). Point activities include airstrips, The physical damage to the terrain that results from off- staging areas, dri l l sites and town sites, Extensive ac- road vehicular movement is potentially more serious on tivities include survey lines, pipelines, winter roads and the wetter, ice-rich permafrost terrain than on drier ter- all-year roads. Disturbance can be quantitatively rain, where visual impact may be the extent of the evaluated in several terms of reference or combinations: damage. 1) visual impact, 2) physical terrain modifications such

56

Table 1. Summary of terrain impacts in North America (af ter How, 1974).

Scvcrily of problem Cause Mechanism Possible cor)sequer~e South o f latltude h.So Nor th of latltude 65O

"I"-

Clearing Removes trees and 1 htrmokarst subsidence, Mlnor subsidence. Minor subsidence shrubs, compresses peat pondlrlg, slumping lo(-al slumping slightly. increases depth of thaw

Cradlng (cut) Fxposes mineral so11 to Subsldcnce, slurnplng, (;ullylng by mechanical Subsidence, slumping, Increased heat Input, In- gullylng croslon, minor sub- gullying (active fo r creases rate and depth sidence more than 5 years) of thaw

Tra f f i c on Keduces vegetation Subsidence, pondlng, Mlnor subsidence, local Short-term effects winter roads cover, rompresses peat slumplng pondlng and slumplng minor subsidence and

layer, increases depth ponding; Long term of thaw effects uncertain

Tra f f i c In Compresses, damages. Ruttlng, therrnokarst Mlnor subsidence Short-term effects of summer and strips off peat layer, suhsldencfl, ponding, mechanical proslon of multiple passes of

increases rate and slurnp~rlg slopes to form gul l~es vehicles: rutting and depth of tha.w subsidence, Long-term

cffec ts. subsidence, gullymg and slumping

Roads dnd Keeps surface generally (;round Icings, choking lclng problem can be reduced or solved with use airstrips clear of snow, allowing and diverting of drainage of proper control measures.

greater frost pcnctratlon during breakup

Winter roads and trails This section reviews studies concerned with the ef-

fects of winter road construction on the terrain and does not discuss methods of construction or the properties of ice and snow roads.

Adam and Hernandez (1977) described the Norman Wells forested test loop, which was hui l t in March 1973 and was subjected t o 36,000 passes by several types of tracked vehicles. For comparison, thaw depths were also obtained from adjacent plots that were cleared by hand and by machine, and areas that were slash-burned. A nearby seismic line, cleared in October 1971, was also used for comparison. Measurement of the active layer thickness the first summer (1973) showed that clearing of the land by hand and by machine had increased thaw to 44 and 49 cm, respectively, as compared to 36 cm in the undisturbed forested site. The ice and ice-capped portions of the snow road had 59 and h3 cm of thaw, respectively. The seismic trail, which had had several summers of increased thaw and additional foot traffic during access to the test site had a thaw depth of 82 cm. Sub- sidence of the surface of the seismic trail was about 30 cm. This area, however, is not underlain by excessively ice-rich sediment. The second year (1974) of thaw showed increases of 10 cm in the control area, 14 crn in the ice road, and 13 cm in the ice-capped snow road. The depth of thaw in the seismic trail in the fourth year was essentially the same as in prior years, suggesting a thaw equilibrium or recovery on that site. The conclusion of the studv was that snow roads could be constructed in a

way that would protect the permafrost, However, additional precautions would be needed on ice-rich subsoils.

Haag and Bliss (1974a), in their energy budget investigations of upland tundra at Tuktoyaktuk, reported on a winter road from which all the vegetation and most of the surface peat had been removed or compacted. Thaw on the winter road was 55 cm compared to 33 cm for the undisturbed surface. The surface subsided a[>- proximately 15 cm.

Younkin and Hettinger (1978) presented results from the lnuvik processed snow road which was bui l t in winter 1973-74. This road received 1000 vehicle passes, mainly with a tandem tractor and trailer. Before the test the active layer thickness averaged 42 cm. The mean active layer thickness in the road and the cleared area decreased 2 cm and 1 cm respectively in 1974 and increased 4 crn in 1975 where i t remained in 1976. No significant change in elevation was noted. These results substantiate other similar findings that the peat layer has a greater influence on depth of thaw than either albedo or the effect of living vegetation (Haag and Bliss 1974a).

Kerfoot (1974) described topographic disturbance resulting from cross-tundra movement of tracked vehicles on the Tuktoyaktuk Peninsula and winter road in the vicinity of Sitidgi Creek. For topographic features which resulted from the 1965 blading of ice-rich tundra, 63.5 cm (41 %) was the result of thermokarst subsidence, and the remainder of the relief was due to removal and redistribution of debris. Subsidence or decrease in

57

ground surface elevation along a winter snow road simulated blading experiment in which the top 3 cm of (1964-1965) was estimated to be 84 cm, while the actual observed was 64. By summer 1966 field evidence indicated that a new quasi-equilibrium condition in the thickness of the active layer had been attained.

Racine (1977) reported on surface disturbance (and subsequent recovery) resulting from a 1974 winter oil exploration and drilling operation on the northern part of the Seward Peninsula. The snow road caused less damage to the vegetation than did the activities at the dri l l storage pads, which were located in stabilized sand dunes and beach ridges.

peat was removed resulted in only a small increase in thaw (approximately 5 cm). It was concluded that erosion and thermokarst resulting from increased soil heat flux in disturbed surfaces are relatively minor problems in the High Arctic.

Abele (1976) and Abele and Brown (1976) presented long-term results of multiple-pass testing of air cushion and tracked vehicles (Weasel) and low pressure tired vehicles at Barrow. For the worst case, thaw continued t o increase for several years fol lowing 50 passes of the tracked vehicle and the air cushion vehicle. The maximum increase in thaw was 11 cm for the Weasel and 5

Summer off-road traff ic cm for the air cushion vehicle. The area contained Rickard and Brown (1974) summarized the results of relatively low amounts of ground ice. Visual deteriora-

off-road vehicle experiments initiated in 1968-71 at Bar- t ion began to improve during the second growing season row and Prudhoe Bay, and in the Mackenzie Delta and following the tests, and in areas that received 25 and 50 the Arctic Islands. passes signs left by the vehicles were barely perceptible

Hernandez (1973) compared the disturbance caused by winter roads and summer seismic lines in the Macken- zie Delta and the Tuktoyaktuk region. In the forested and shrub communities north of Inuvik, silty soils thawed 60-70% deeper in the disturbed areas than in the controls (16-22 cm in the control and 27-40 cm in the disturbed areas over three summers of observations). In a tall shrub community near Tununuk Point, thaw doubled in the disturbed areas (29 cm in the control and 60 cm in the center of a seismic trail in early July). For tundra communities near Atkinson Point, the depth of thaw under trails increased only slightly, although the thaw under an old airstrip on which 1-2 m of sand had been placed in the mid-1950's more than doubled. In a tussock tundra community near Reindeer Station, a trail made by a vehicle train resulted in erosion, slumps and more than doubling of the thaw depth by early July. In the Tuktoyaktuk region winter roads used for several winters produced thaw 27 to 44% deeper under the center of the road than in the adjacent undisturbed areas. Where the surface peat had been worn down over ice wedges, thermokarst and gullying occurred. A comparison was also made of summer and winter seismic lines through similar plant communities. Thaw averaged 58 cm under the summer seismic line and 29 to 38 cm under the three winter lines (controls ranged between 19 and 30 cm in mid-july). Subsidence of the bladed summer trail was estimated at 25-30 cm and thermokarst ponds formed where ice masses were exposed. Winter trails did not result in massive thermokarst subsidence since only a small amount of soil was exposed. For this

after 4 years. The visual impact is more severe in wet tundra than in dry, polygonal tundra.

In a related study Abele et al. (1978) initiated another multiple vehicle test at Lonely, Alaska, the current base camp for oil and gas exploration in the National Petroleum Reserve, Alaska. This test involved 1, 5 and 25 passes of several types of Rolligons and a Nodwell tracked vehicle. After two seasons, differences in thaw depth were negligible in all test lanes. In a related test at Prudhoe Bay single and multiple passes were made by a Rolligon across a range of vegetation and soil types early in the summer (tverett et al. 1978, Walker et al. 1977). The tundra was extremely wet and thaw still shallow (12-28 cm). Thaw observations were made and impact ratings assigned at 32 stations. By mid-July of the second summer (1977) following the test, differences in thaw between the track and the control surface were either negligible or the thaw averaged 3 crn dee1,er in the trail (pets. comm., Walker). In these observat.ions no damage had spread from the Rolligon test area to the adjacent tundra. This is in agreement with the Muskeg Institute's observations (Kadforth and Burwash 1977) that rarely did deterioration of the terrain go beyond the immediate tracks.

Radforth (1973) reports on the long-term effects at tracked vehicle test sites at Tuktoyaktuk and Tununuk, N.W.T., and Shingle Point, Yukon Territory. 1.hermokarst development was related to the level of initial disturbance, although all terrain types tested stabili7ed within two years. I t was concluded that vehicle traffic in excess of 40 passes should be avoided to minimize surface dis-

region, thaw generally increased 80 to 100% where turbance. mineral soil was exposed, 30 t o 50% if the peat remain- Gersper and Challinnr (197.5) reported on physical ed intact, and 10% if the plant cover was little altered, changes in an old Weasel trail at Barrow. Soil bulk den-

Addison (1975), Babb (1977), Rabb and Bliss (1974a) sities and temperatures were higher, thaw was deeper, and Barrett (1975) reported on a series of controlled sur- and moisture was lower under the track than in the adja- face manipulations and Observations of disturbances at cent undisturbed tundra. Thaw in the control area was a number of extensive sites in the Canadian Arctic 30 cm while at several positions in the track it averaged Islands. Mult ip le passes (10, 40 and 60) of a vehicle with 42 cm. The wetter sites had greater thaw. Where the rubber tracks (Ranger) on a meadow site resulted in no trails intercepted ice wedges close to the surface, significant thaw differences during the first season. A shallow thermokarst pits had formed.

58

Sparrow et al. (1978) studied five trails on alpine soils and vegetation in central Alaska and found that in mid- J u l y thaw depths were more than 1 m under the trails and ranged between 40 and 70 cm in the undisturbed tundra. The wetter areas and side slopes, which are highly erodable, showed the greatest visual impact.

Rickard and Slaughter (1973) monitored permafrost degradation and erosion on a tractor-cleared trail and on a hand-cleared access trail near Fairbanks. Under the severely eroded tractor-cleared trail depth of thaw had increased to between 132 and 189 cm while thaw in the adjacent undisturbed area was 36-48 cm. On the hand- cleared trail thaw had increased from control values of 54-59 cm to 127-182 cm. The hand-cleared trails had been used for four summers while the bulldozed trail was used once.

linear transportation systems and other activities Roads, railroads and pipelines have considerable

potential for modifying the highly variable permafrost terrain they traverse. The response of the permafrost environment varies, depending on physical and thermal conditions. Proper route selection, drilling programs, and design can eliminate much potential terrain disturbance. Recent experience along the Livengood to Prudhoe Bay haul road, the Dempster, Alaskan and Mackenzie highways and the old Canol road (Fradkin 1977) has produced numerous documented examples of terrain disturbance due to road construction. Major causes of disturbance due to linear placement of gravel for road beds and pipelines are:

1. Concentration of sheet flow through drainage structures and subsequent downslope thermal and hydraulic erosion in ice-rich permafrost,

2 . Cuts through massive ground ice and subsequent accelerated melting and thawing, with production of sediment and potential for rapid headward erosion.

Secondary effects are: 1. Local surface impoundments where ponding may

accelerate thaw adjacent to and beneath the roadbed and result in local impact on vegetation.

2. Increased snow accumulation due to drifting and potential warming of the permafrost.

lsaacs (1974) investigated the thermal modifications caused by the Canol road, which was built in 1943 between Norman Wells and Whitehorse. As a result of surface warming the underlying permafrost has warmed considerably. Calculated thaw depths, assuming conduction processes only, underestimated the depth of thaw as observed in drilling. In one area thaw was calculated to be 15 m but no permafrost was found in the 25-m-deep hole.

Pufahl et at. (1974) reported on a field reconnaissance of road cuts in northwestern Canada and parts of Alaska. I t was noted that the greatest risk of initiating unstable slope conditions arises in areas of glacio-lacustrine silts and clays which contain large amounts of ground ice. They concluded that instability of natural slopes is the best indicator of potential instability of cut slopes. Their observations indicated that cut slopes need not be a

serious impediment to routing transportation arteries across permafrost.

Berg and Smith (1976) reported on the slope stabiliration of the TAPS road over a 6-year period. They concluded that natural processes of slope stabilization in ice-rich cuts can be enhanced if: 1) lateral drainage ditches are wide enough to allow deposition and removal of material, 2) backslope cuts are cut nearly vertically and 3) the tops of cuts are hand cleared to a width equal to one and one-half times the height of the cut.

Berg et al. (1978) reported on the initial thaw performance of the Yukon River-Prudhoe Bay haul road and indicated that concentration of sheet flow through culverts on the ice-rich slopes is a serious design and terrain problem.

McPhail et al. (1976) also reported on stabilization of cuts along the haul road. The Happy Valley road cut is cited as an example in which thawing of gravelly silt caused considerable maintenance problems. Special restoration techniques were required. The adjacent cut with massive ground ice healed naturally.

Huculak et al. (1978), reporting on the Dempster Highway construction, said that the prime design con- cern was to preserve the permafrost to a tolerable degree of grade distortion.

Considerable attention has been devoted to erosion control and related revegetation during and after the construction of the trans-Alaska pipeline. In an initial report Johnson et al. (1977) documented the summer 1975 performance of initial revegetation and erosion control techniques and presented illustrated examples of slides, slumps, thermokarst, and thermal erosion along the route. The natural folding over of the organic mat on road cuts was successful in stabilizing cuts.

The Arct ic is not the only tundra region where pipeline construction activities may cause temporary disturbance (Brown e t al. 1978). As an example, Marr et al. (1974) described placement of a gas line which crossed the alpine tundra of Colorado. Erosion potential during spring runoff when the ground is frozen was considered high and the routing was selected to intercept a minimum of existing drainages. Construction was delayed until the turf vegetation was dry to avoid damage, and techniques for placing the turf back over the trench were experimented with for purposes of restoration.

The experience gained in road and pipeline construction across permafrost and muskeg terrain has led to revised environmental design and construction guidelines for roadways on permafrost (Murfitt e t al. 1976, Lotspeich and Helmers 1974, Curran and Etter 1976). Some major points are listed: 1) The vegetation mat should remain in place to minimize thermal erosion and thermokarst. 2) Grading, particularly in ice-rich soils, should be avoided and fills used as an alternative. 3) Natural drainage should be maintained and additional drainage for runoff considered. 4) Design should incor- porate tolerable amounts of settlement. 5) Surface and groundwater seepage areas and frost-susceptible

59

materials should be avoided where possible. 6) Drainage structures should be designed to minimize water-related erosion. 7) Embankment surface drainage must be ac- counted for in the design and maintained during construction.

French (1975) described a case history of human- induced thermokarst due to construction of a gravel airstrip a t Sachs Harbour on Banks Island between 1959 and 1962. Hummocky-type terrain with maximum relief of 100-150 cm has been created by progressive subsidence and thermokarst modification. Thaw depths

.were 10-20 cm greater under the disturbed sites, After 10-12 years, the thermokarst process continued but at a lower rate, although thcrmokarst forms were well- developed several years after the initial disturbance.

Price et al. (1974) described wet spots found on surfaces scraped for runways and other access sites on the Queen Elizabeth Islands. The spots are associated with non-sorted polygons, As the underlying ice-rich zones around the margins of the polygons thaw, due to the disturbance, moisture is drawn to the surface. Over the course of several summers the excess ice is removed and the spots dry out.

Walmsley and Lavkulich (1975) examined the effects of organic matter removal on the active layer over a period of one year in an area 80 k m east of Fort Simpson. In a peat plateau, thaw in a trench increased from 30 cm in July 1971 to 90 cm in July 1972. The disturbance influence was still measurable 2 m from the trench, with thaw 40-60 cm deep. In a polygonal bog, lateral thaw along an ice wedge increased the disturbed area to more than 4 m.

In a study of a 1949 exploratory drill site in northern Alaska Lawson et al. (1978) observed thaw as a function of intensity of disturbance; mean thaw depth was 53 cm on intensely disturbed sites as compared to 32 cm on the least disturbed.

Oil spills Research on experimental terrestrial crude oil spills

started in 1970 at Barrow (Deneke e t al. 1975) and at three locations in the Mackenzie Delta (Wein and Bliss 1973b). Additional experimental spills were conducted in Fairbanks (Jenkins e t al. 1978), Barrow (Everett 19783, Prudhoe Bay (McKendrick and Mitchell 1978, Walker et al. 1978) and in Canada (Hutchinson et al. 1976, Mackay et al. 1975a. b). Although the intent of many of these spills was to evaluate the fate of the crude oil and its effect on biological components, soil temperature and thaw depth were also measured to evaluate the potential effects of the movement of the oil on the permafrost table.

Hutchinson and Freedman (1975) and Freedman and Hutchinson (1976) reported insignificant differences in the active layer under spills at Norman Wells and Tuktoyaktuk compared to their controls. During a three- year period of measurements the only exception was a wet meadow spill at Tuktoyaktuk which had much deeper thaw than the control in both 1974 and 1975. Summer spills are more harmful to vegetation than

winter spills. Oiled plots tend to have higher surface temperatures due to increased radiation absorption on the surfaces darkened by the oil (Haag and Bliss 1974a). However, these higher surface temperatures do not generally lead t o increased depth of the active layer on the oiled sites. Extra energy absorbed apparently is lost as latent heat of evaporation and the resulting drier surface forms an effective thermal barrier.

Uickman and Lunardini (1973) observed thaw depths one year after applying crude oil to hummocky terrain at Inuvik. Thaw increased between hummocks and decreased under the hummocks. These results indicated the rather complex behavior of oil in the active layer.

At Barrow, Everett (1978) observed a marked increase in thaw depth during the first two summers after applica- t ion of crude oil (1975 and 1976). The effect diminished in 1977 and it was suggested that the effect is probably of short duration, on the order of five years or less.

Hydrocarbons persist in the active layer for more than 30 years as observed on 1948 and 1949 dri l l sites in northern Alaska (Lawson et al. 1978) and along the Haines- Fairbanks pipeline for a period exceeding 20 years (Deneke et al. 1975). In the latter, the permafrost table receded where vegetation had been killed, but where a thick moss layer existed changes in active layer thickness as well as erosion were minor or not detec- table. At the Fairbanks 1976 winter and summer spills of hot crude oil there was little movement of oil downslope after the first season (Jenkins et al. 1978). An increased rate of thaw in July and August was noted for the summer spill as cornpared to the winter spill. Natural oil seeps at Cape Simpson indicated thaw in the seeps was 40-50 cm deep and diminished abruptly to 25 cm adjacent to the seep (Deneke et al. 1975). Temperatures were 3 to 5oC warmer in the seeps during the day at 10-cm depth and 1 - 2 T warmer at night compared with the adjacent tundra.

Containment of spills by damming in permafrost and damage by vehicles could result in increased disturbance. Crcene et al. (1975) proposed a portable cor- rugated metal sheeting which could be installed by hand to contain the oil. Other techniques involve cutting nar- row trenches (30 cm wide) which intercept the oil, which can then be pumped. It is suggested these techniques might be less degrading to the environment than burning, although McKendrick and Mitchell (1978) report no significant thermal or thaw changes resulting from burning spilled oil in Alaska.

Mackay et al. (1975a) indicated that some effects of oil on the thermal regime could be: 1) an albedo increase that would increase the mean surface temperature by IO%, 2) an increase of 10.20% in thermal conductivity if the oil was physically trapped in voids contained in mosses, 3) an increase in thaw if oil occupies the voids instead of ice since the latent heat to me l t ice would not be required, and 4) an increase in the soil temperature due to reduced evaporation caused by the oil f i lm.

Raisbeck and Mohtadi (1974) developed a simple model to predict the movement of oil on permeable and impermeable surfaces. Oil is l ikely to spread above the

60

groundwater table. The question was raised whether the oil's ability to absorb extra energy would in fact result in greater thaw. Oil-inundated soils have a lower thermal conductivity, which reduces heat transfer. This may be the reason for the lack of strong evidence that oil in soil increases thaw.

Fire Fire in the tundra and northern coniferous forest

(taiga) is a common natural process frequently initiated by lightning storms. Viereck (1973,1975) states that "fire is undoubtedly one of the most important environmental factors affecting taiga ecosystems." In Alaska, of the 400,000 hectares burned between 1940 and 1969, nearly half was treeless bogs, fens and tundra. Hernandez (1974) reported that one million hectares burned in the period 1962-71 in the District of Mackenzie, N.W.T., and the Yukon Territory north of 67O latitude. Wein (1976) reported on over 5 0 tundra fires, mostly in western North America. Shilts (1975) added to the list of tundra fires for the eastern Arctic, aided by the use of satellite imagery. Generally tundra fires are smaller than forest fires because of the lack of combustible materials.

Following fire, the active layer undergoes some modification and usually increases in thickness. Secon- dary effects of fire on the permafrost terrain result from erosion and gully formation, particularly where fire lines have been bladed or cleared with bulldozers (Evans 1976).

Rowe et al. (1975) and Johnson and Rowe (1977) investigated the characteristics of forest fires and related vegetation responses in the upper Mackenzie Valley and Caribou Range. The rapid response of permafrost to fire was seen in the form of s i l t and earth flows which developed within a year of the fires.

Wein et al. (1975) examined slumps in the area of the 1968 lnuvik fire and found that most of them had occurred since the fire. They concluded that fire does initiate slumps or soil flows when the landscape is unstable. Vehicle tracks caused more damage on burned areas than on unburned areas (Wein et al. 1975). First season active layer depths resulting from tracks on the burned areas increased about 10 cm (20%) in a black spruce cotnmunity and almost 20 crn (25%) in a birch community.

Mackay (197713) fol lowed change in the active layer in the lnuvik fire which burnt an area of forest and tundra. The depth of thaw at five sites was measured in August of each year from 1968 to 1976. On a hillside site consisting of ridges and depressions, the active layer thickened rapidly for the first 4 or 5 years and was still increasing slightly after 8 years. The active layer on the hillside site under depressions thickened 57 cm to approximately 90 cm, and under ridges it thickened from 54 cm to approximately 115 cm. Due to i t s high ice content the hillside site has subsided nearly SO cm. However, with time, as the vegetation changes and the permafrost aggrades upward, the ground surface will likely rise. Therefore, the long-term disturbance to the

permafrost at this and other fire sites remains to be fu l ly evaluated.

Viereck (1973), however, reported that depth of thaw under burned and unburned sites in four black spruce stands near Fairbanks was not significantly different (total thaw about 45 cm). Hall et al. (1978) noted a slight increase in thaw one month after a tundra fire in northwestern Alaska. In cottongrass tussock tundra at four fire sites in Canada and Alaska, Wein and Bliss (1973a) observed a 3540% increase in thaw in June with an overall late summer increase of 1525%. Cottongrass recovers rapidly after fire, and unless the organic mat has been consumed, long-lasting disturbance of cottongrass tundra in the form of thermokarst or erosion is unlikely. Haag and Bliss (1974a) reported results of an experimental controlled fire on tundra at Tuktoyaktuk. Thaw increased from 36 t o 46 cm by the end of the first summer.

Recently, McKendrick and Mitchell (1978) reported that the soil did not warm appreciably during controlled burning of oil. In three burns at Palmer, Fairbanks and Prudhoe Bay, soil temperatures stayed below lethal levels for the vegetation at the 4-cm depth. Viereck (pers. comm.) similarly indicated that soil temperatures immediately after an experimental burn in the Fairbanks area did not increase below a depth of 15 cm. The heat of the lnuvik fire did not contribute to the initial thawing (Mackay 1977a).

Rouse and Mills (1977) summarized a three-year study of microclimatic changes which accompanied burning of lichen woodland in the Northwest .Territory. Summer- time soil temperatures were 3.0 to 5 . 5 T warmer in the burned areas; however, there was apparently no long- term soil warming. The soils in burned areas are drier and remain so for many decades. Kane et al. (1975). in a study of soil moisture and temperature near Fairbanks, concluded that the thermal and moisture regimes of soils undergo considerable alteration because of fire. These changes are related t o long-term changes due to modification in the surface layers.

The rapidly burning fires on old lake beds and polygonal ground are unlikely to produce long-term disturbance since the underlying wet organic soils have not been drastically modified [Shilts 1975). The more in- tense and hot fires which do burn the peaty materials are l ikely to alter the depth and configuration of the permafrost surface. This i s particularly s o around mineral frost scars, where thaw increases adjacent to the scars. It has been suggested that the intensity of frost action and the formation of frost scars may be a function of the frequency of tundra fire (Viereck, pers. comm). Pettapiece (1974) described the role of fire in cyclic aspects of hummocky soils. The loss of the surface organic layer due t o fire initially promotes the downward retreat of the ice- rich upper permafrost. A loss of volume creates settlement in the center of ,the hummock. Subsequently the increase in the vegetative mat results in an aggrading permafrost table, which in turn results in an elevation of the hummock.

61

CRYOGENIC PROCESSES AND REGIONAL DISTRIBUTION OF PERMAFROST IN THE USSR

.Human disturbance of permafrost terrain gives rise t o cryogenic and other geological processes which alter the landscape in undesirable ways. The damage which results is generally slow to heal, a characteristic of the northern environment (Kriuchkov 1976). The cryogenic processes such as frost heaves, fractures and icings are associated with increased freezing of soils in permafrost areas. Thermokarst, thermal erosion and subsidence, solifluction, and landslides are associated with thawing. The specific causes and rates of cryogenic processes are dependent upon many environmental factors (Romanov- skii 1978a).

The newest geocryologic map of the USSR, including the arctic shelf, provides the basis for delineating areas where cryogenic processes are probably active (Kudriavtsev e t al. 1978b). Offshore over most of the arctic shelf and basin, permafrost is widespread, with the exception of the continental slope under 200-900 m of water and in zones influenced by the warming effects of discharges from large rivers. The thickness of the frozen sediments in the shelf area of deep water can be up to 30 m (Are 1978a).

In the southern part of the permafrost region of the USSR there is island permafrost. Farther north the size of these islands increases, as does the thickness of the frozen stratum, Its temperature is O0 to - L O T . In the northern regions there is continuous permafrost with temperatures - 3 O to below -15OC and thicknesses up t o 500-700 m. The greatest thickness of ground with negative temperatures (800-1500 m) is to be found in the Paleozoic stratum of central Siberia, where ground containing supercooled salt solutions below O0C underlies the frozen layer (Kudriavtsev 197813). In the high altitude regions (Tian Shan, Pamiro-Alai) permafrost covers an area of more than 100,000 km2. Sporadic permafrost begins t o appear at altitudes of 2200-3200 m; at altitudes of 2700-3700 m islands of permafrost occur; discontinuous permafrost is t o be found at 3200-4100 m; and continuous permafrost at altitudes above 3500-4400 m. The greatest permafrost zone thicknesses (more than 860 m) and the lowest negative temperatures ( -.lY°C) are found in rock massifs (Corbunov 1978). Significant depths of bedrock freezing are found in the Pai-Hoi ridge (Polar Urals), where the frozen layer may be up to 800 m thick (Oberman 1978).

The rates of seasonal thawing and freeLing of soils to which cryogenic processes are closely related are found in the schematic map by Vtiurina and were also investigated ky Cherniad'ev (1976). Cryogenic processes may exist beyond the southern limit of permafrost, which is not only sensitive to climate but to human disturbances (Makeev 1977). The cryogenic processes develop differently in various zones (polar deserts, tun-

dra, taiga, forest-steppe and continental or maritime climates). The regional climate determines the features of the cryogenic processes in the northern permafrost zones, whereas meso- and microclimates are more in- fluential in the southern and discontinuous zones (Gavrilova 1978).

The type and thickness of the organic cover greatly influence the depth of seasonal thawing. Research in northern Tyumen Oblast on seasonal thawing under various types of tundra vegetation indicated that a moss-lichen cover exerted the greatest influence on the thermal regime of the ground, whereas a sedge- sphagnum cover had the least influence (Skriabin 1978).

The presence of underground ice is the main condi- t ion necessary for large scale cryogenic processes such as the formation of thermokarst features and thermal erosion. The distribution of underground ice i s irregular (Vtiurin 1978) wi th separate areas of sheet ice, ice wedges, and other types of ground ice. Ice wedges have the largest areal distribution (see Figure 1) . Thc character of cryogenic processes depends on the relationship between the landscape components. The composition of the soils and their ice contents, the topography, and the climate are related to the microclimate, vegetation, snow cover, and ground temperature regimes. Human- induced changes in these regimes determine the character of the resulting technologically produced landscape (Balokaev 1978, Fel'dman 1977, Mel'nikov 1976, Mel'nikov and Tolstikhin 1974, Shvetsov 1973).

Cryogenic processes resulting from natural causes such as changes in climate, plant succession, and geomorphic. processes take place slowly and can be measured over many years. Thermokarst in northern Yakutia has a long and complicated history (Gravis 1978, Konishchev 1974) and is related to cooling and warming during the Quaternary. New cryogenic processes occur in northern sections of West Siberia as a result of swamp formation in the taiga and its replacement by sparsely forested sphagnum and lichen bogs. Deep freezing occurs on the growing hillocky peat bogs which are more snow free as a result of wind exposure in these open areas. Soil temperatures are decreased by 4OC (Belopukhnva et al. 1976).

Natural cryogenic processes have been investigated in detail: thermokarst (Gravis 1978, Romannvskii 1Y77, Shur 1974, 1977, Sukhodrovskii 1976); processes on slopes (Sukhodrovskii and Gravis 1976, Zhigarev 1975b); frost action (Crechishchev 1978, t'odbornyi 1978; Romanovskii 1977b, 1978a, k, Hotnanovskii and Liebman 1975), frost heaving (Nevecheria 1975, Rntnanovskii 197813) and gully formation (Kosov and Konstantinova 1975).

Human-caused surface disturbance increases the rate

62

Figure I. Ice wedge distribution in percent of area for permafrost regions of the U S S R [Vtiurin 1975).

of cryogenic processes. After the active phase following disturbance, which usually takes 2-3 years and results in topographic changes, changes are more gradual and may cease after about 10 years. The result is the formation of a new landscape (Crave and Sukhudrovskii 1978, Grigor’ev 1977, Kriuchkov 1976, Mel’nikov et al. 1977).

The direct cause of changes in the cryogenic processes in permafrost regions is modification of t.he surface heat balance. Partial or complete removal of the surface organic layer in the northern section of West Siberia increased the radiation balance by 5-15%, the mean ground temperature by 0.7 to 2 O°C, and the depth of seasonal thaw by 2-3 times (Pavlov 1978). Hutnan ac- t ivi ty results in greater changes in the surface heat balance than do natural causes (Mel’nikov et al. 1977a, Sergeev and Skriabin 1978).

The modification in the surface heat balance can br either negative or positive and depends on the particular permafrost zone and the type of impart. Surface disturbance in one area can cause an increase in ground temperature, followed by the appearance or further development of thermokarst, thermal erosion and solifluction, while the same disturbance in another area can cause frost heaving, icings, and cracking of the ground (Alekseev 1977, Helopukhova et. al. 1976, kel ’dman 1977, Lisi tsyna 1977, Makeev 1977, Moskalenko 1975a, b, c, Moskalenko et. al. 1978, Romanovskii 1978a, h, Romanovskii et al. 1978).

Human-induced cryogenic processes have not been well investigated. Their classification and Some features have been investigated in a regional approach (Adushkinov and Borishenko 1975, Arkhangclov et al. 1975, Chizhov et al. 1977, t f imov and t f imova 1975, Kulakov 1977, Leshshikov 1975, Maksimova 197713, Maksimova et al . 1975, Nevecheria et al. 1975, Neizvestnov and Postnov 1975, Poltev c t al. 1975, 1978, Stepanov 1977).

HUMAN-INDUCED TERRAIN DISTURBANCE AND CHANCES IN GROUND TEMPERATURE REGIME

The principal types of disturbance, including the destruction of topography, can be treated as part of the study of the formation of human-induccd landscapes. The specific features of these landscapes are determined by the type of disturbance, the consequent cryogenic and other geological processes, and the characteristics of the original landscape. There are only partial references to this subject in the literature (Ermakov et al. 1977, Kondrat’ev et al. 1977, Leshchikov 1975, Poltev et al. 1975, 1978, Serdiukova and Vnukov 1975, Surdiukova et al. 1975, Sokolov 1975, Sukhodd’skii, 1975).

6 3

The disturbance of plant and soil covers The polar deserts have a very thin and discontinuous

plant cover, with areas of exposed mineral soil that usually are larger than the areas covered by vegetation (Matveeva and Chernov 1976). Disturbance of this type of cover by vehicles or reindeer herds has l itt le effect on the depth of summer thaw, and in spite of high ice content in the ground, little melting occurs. The main disturbance is destruction of reindeer pasture (Andreev 1977). The same is true in the taiga where damage to the moss cover leads to loss of plant cover in treeless sites (Belyi 19771.

In the forest-tundra and northern taiga zones (fluvio- lacustrine plains) of Western Siberia the removal of the surface moss cover from hummocky peat land and muskeg which are underlain by frozen sand and s i l t s does not lead to significant increases in ground temperatures or depth of seasonal thaw. This is explain- ed by the low thermal conductivity of the peat, which usually dries out at the beginning of the summer. However, once the peat cover is removed, the sands and s i l t s thaw deeper, thermokarst occurs, and lakes and bogs develop (Moskalenko 1975b, c, Nevecheria et al. 1975, Slavin-Borovskii 1975).

Investigations from different locations in the tundra and forest-tundra of Western Siberia during 1974 and 1976 have shown that the differences in moisture content of the ground and the depths of seasonal thaw are not s o much conditioned by zonal climatic factors as they are by ecological conditions. These ecological conditions are the factors which determine the degree to which vegetation and soil cover disturbance will affect ground temperatures, moisture and summer thaw (Table 2).

Removal of the tree cover in the southern taiga and forest-steppe zones of Western Siberia decreases the depth and increases the density of the snow cover on the treeless sites, which results in a lowering of the ground temperatures. Islands of permafrost develop and ”short- term” permafrost appears where there was none previously. Landscapes are created with characteristic processes of frost heaving and frost cracking (Makeev 1977, Tshigir et al. 1977).

In both the tundra and taiga of Western Siberia, where removal of vegetation and surface soils exposes frozen sands, the newly thawed, dry sands are blown by strong winds, forming human-impacted landscapes termed “sandy arenas.” The sand storms damage populated areas (Shilova and Mamaev 1977). Naturally occurring extensive areas of blowing sands or tukulans occur in central Yakutia.(Shepelev 1976).

In the northeastern Siberian lowland, with its massive ice wedges, the disturbance and removal of the plant cover and soil mantle increase summer thaw, and thermokarst and thermal erosion are widespread. Hillocky terrain with water-filled depressions and cemetery mounds (baydzherakh) is nearly impassable and gullies form (Efimov and Efimova 1975, El’chaninov and Shor 197513, Zhigarev 1975a, Tyrtikov 1975). The shores and slopes of thermokarst lakes and sea coasts formed from

ground containing ice are also subject to erosion (Are 1978b, Troitskii 1977).

In the taiga of Central Yakutia, where there are extensive masses of ground ice, clearing of vegetation, removal of tree stumps and disturbance of the soil mantle cause thermokarst. This process is slowed by the hot and dry summer climate and is l imited to the area in which the vegetation was damaged. The surfaces of the sites cleared for agriculture soon become hummocky and boggy (Zamolotchikova and Smimova 1974). Systematic observations at various sites in the region around the city of Yakutsk (Zabolotnik 1978) have shown that clearing of trees while maintaining both the snow and moss cover results in considerable warming of the ground. Four years after forest removal, ground temperatures had increased by 1 . 3 T a t the 3-m depth. However, simultaneous removal of the forest, moss and snow covers leads to considerable cooling of the ground. Over a four-year period of observation, ground temperatures decreased by 1.7OC in comparison with natural conditions.

In drained and dried sites, sodium sulfate and sodium chloride salinization of the soil frequently occurs and about 30% of the agricultural land becomes unusable (Elovskaia e t al. 1977a. b). Where fire occurs and massive ground ice is present, “pyrogenic tundra” forms (Kriuchkovl976, Kurbatskii 1977). In mountainous areas, altiplanation terraces become more active following the disturbance of the plant cover (Kudriavtsev et al. 1977).

Destruction of ground and underlying rock Excavation during construction and mining, and

building of dikes, embankments and spoil piles cause intensive surface disturbance. These activities influence all permafrost zones and particularly sites with high content of ground ice.

During open pit or underground mining and associated construction activities, not only are the soil and plant covers destroyed, but shocks and vibrations from machinery disturb soil structure. Runoff water from mining results in erosion. Changes in topography and the increased chemical and sediment loading of rivers and lakes lead to impacts far beyond the boundaries of direct activity. In areas with soils of high ice content, especially in northeastern USSR, human-impacted landscapes form consisting of cemetery mounds, landslides of thawed earth materials, and other forms of thermal denudation and erosion, and slopes are lowered (Zhigarev 1975a).

Waste rock piles formed during mining activities and construction of embankments are heat insulators. In areas where the permafrost temperatures are relatively high, taliks for! within 2-3 years. Piles and embankments disrupt the hydrological regime of adjacent areas and stagnant surface waters accumulate. The taliks form as a result of stagnant waters which coalesce with those formed under the waste piles and embankments, and thermokarst may develop if sufficient ground ice is present.

64

Table 2. Temperature-moisture regime of soil and ground under natural and disturbed conditions (modified from Moshalenko and Shur 1978).

Avg rnol$turt! Max

temp r o ~ l lclycr thaw Avg ground 111 SO-cm s u r r m e r

Natural ecological complex f "C) lnlnli ( m ) .- . .~ . . .

Southern Tundra (1974)

1 Spotty tundra on sandy loam deposits d Sandy lo,~nl spot - f? 2 h. Grass-shrub cover - 5 7

2. Shrub-moss tundra on peaty sandy loc~rn d e p o s ~ t ~ -611 3 Polygonal tundra on peaty sandy loam

d Shrub-lichen-sphagnum polygon 7 3 h Crass-sphagnum trough - 7 2

Forest Tundra (1976)

179 I h7 193

1.15 1 06 0.52

0 35 0 43

4. Spotty polygonal tundra on sandy deposits a Sandy spot b. Shrub-lichen polygon

a Loamy spot h. Shrub-lichen cover c. Loam with vegetatlon removed d Peaty loam with vegetation removed

5. Spotty larch shrub on peaty loam

- - 1 . 3

- - 2.3

- 2.5 -

49 35

171 165 160 172

1 8 1 .7

1 49 1.3 1.62 1 52

Northern Taiga

6. Shrub-sphagnum-lichen peat moss a. Hummock - 0.8 260 0.63 b. Depression between hummocks - 285 0 57 c . Same surface with vegetation removed -. 0 R 248 0.7

a. Mound - 0 . 7 200 0.92 b. Depression - 220 0 65 c. Same surface wlth vegetation removed

Mound - 0 . 7 1 60 1.43 Depression - 1 a0 1.3

7. Peat-rnineral mound with shrub lichen cover

Human-impacted terrain, and specifically waste rock piles, is unsuitable for land use; it is also the cause of chemical pollution of water and requires restoration and rehabilitation (Bol'shakov 1975, El'chaninov and Shor 1975a, b, Krylov ct al. 1975, Neizvestnov and Postnov 1975, Peretrukhin et al. 1975, Sever'ianov et al. 1975).

Long, deep quarries in the southern part of the permafrost tone are a source of new permafrost formation and accompanying cryogenic processes, if water does not accumulate in them (Klimovskii 1978).

Experience with coal mining operations in permafrost areas has shown the danger of icings and shaft cave-ins where the surface has collapsed to a depth of 60 m. Air and water which enter through the shaft lower the stability of the ground (Sever'ianov et al. 1975, Sever'ianov and Popov 1975). It has been shown that roof thaw depends on the number of galleries and the distance between them (Fedorov 1976).

The influence of urban development Towns and villages represent a particular type of

human-impacted terrain which results from very com-

plex geological and engineering processes. A classifica- t ion has been drawn up of factors related to human impact and conditions that influence the temperature regimes at the airlground interface, and of ground waters in populated areas. Both direct and indirect factors that contribute to increasing or lowering the temperature are indicated (Kotlov 1977).

L.N. Khrustalev (1975) studied the influence of large buildings on changes in the geocryological conditions. In the northern and central permafrost zones, i t was established that the properties of the snow cover exerted the greatest influence on heat exchange on ground that has been built upon. In southern regions, destruction of peat moss cover, use of artificial surfaces, and the distribution of buildings significantly influence the heat regime, since they change the conditions of moisture movement into the ground (Porkhaev and Shchelokov 1973). Changes in the thermal balance at the ground surface resulting from human impact in the city of Vorkuta led to partial degradation of permafrost for 80-90% of the region (Gorbacheva 1975). Within the main areas of permafrost, towns and villages generally lower the

65

0

5 E

f IO 0 n

15

Figurl

I . - I -.I

2. ldealized cross section of buildings and road in Norilsk showing the changes in ground temperature resulting primarily from differences in winter snow accumulation and related methods of snow removal, A is fine icy sand with moisture of ZS%, and 6 is clayey loam gravel with sand lenses. [Bobov and Lapochkin 1974.)

ground temperature (Porkhaev and Shchelokov 1973). Long-term measurements of ground temperature in Norilsk began in the tundra prior to construction and were then taken at various sites and different times as the city building progressed. Three to nine years after building commenced, ground temperatures in the city rose, but 19 to 30 years later they were lower than they were before development (Figure 2). The reason for the decrease was increased removal of snow within the city area when mechanization was introduced (1950-60). Un- til that time, snow was removed manually and remained in the yards (Bobov and Lapochkin 1974).

In Yakutsk, apart from decreases in ground temperature, particularly below old sections of the city, intensive salinization of groundwater and of the silty loam soils by chlorides of sodium and magnesium has been observed as a result of the penetration of saline Water of less than OOC (about 100 grams per liter) into the active layer and taliks below lakes. Salinization is associated with higher rates of evaporation and low precipitation during the hot summers in a city with insufficient drainage and other amenities (Anisimova 1975).

FORECASTING, MODELING, AND EVALUATION OF TERRAIN SENSITIVITY

The problem of geocryological forecasting, which should be considered as part of ecological forecasting, is very complicated. Most of the investigations represent individual solutions that are related to specific types of construction and that have been based on limited evalu- ations of isolated geocryological features of the natural environment (Kudriavtsev et al. 1978d, Shvetsov et al. 1973). The prediction of human impact is important to env i ronmen ta l p ro tec t i on (Kondra t ' eva 1978 , Maksimova 1977a). Working out a theory for human- impact forecasting is a very complicated matter. The thermal regime of the ground and fluctuations in the depth of seasonal freezing and thawing are of great importance in forecasting these processes. Phase transi-

tions of water play the greatest role in these cryogenic processes, It has been established that albedo and radiation balance are the major factors in determining the energy budget of natural terrain. Relationships between the radiation budget and the mean annual temperature of the ground have been established (Pavlov 1975, 1978a, b).

The changes in the temperature regime of ground of various compositions and thermal conductivity and under various geological conditions are determined by the structure of surface heat balance (Balobaev 1974, 1978, Dostovalov 1978, Kondra'teva 1978, Moskalenko 1975~). C.M. Fel'dman (1977), following the ideas of V.A. Kudriavtsev (Kudriavtsev 1974, 1978, Kudriavtsev and Maksimova 1978, Melamed and Medvedev 1974), has developed techniques for forecasting the temperature regime of the upper layer of permafrost in relation to specific geological and geographical conditions. There are various possible approaches for conducting investigations at a particular building site (Alekseev 1977, Caragulia et al. 1975, Konstantinov et al. 1Y77, Kulakov 1977, Nevecheria 1975, Peretrukhin 1975, 1978).

Geological surveys furnish much of the information necessary for qualitative and quantitative forecasting (Kudriavtsev and Maksimova 1978, Kudriavtsev et ai. 1978~) . As a result of these surveys, an engineering- geological map of permafrost is prepared and predic- tions of changes to the natural environment and a forecast map or chart are compiled. A regional classification of soil and rock types and a comprehcn- sive land use evaluation of natural and human impact development have been prepared (Kudriavtsev et al. 1978~1, d, Badu and Trofitnov 1977, Veisman 1977, Gor- bylev et al. 1977, Mel'nikov et al. 1978, Nevecheria and Moskalenko 1977, Nefedova and Chizhov 1975).

In order to accelerate the investigation of new areas that are being considered for development, the method of "preconstruction impact studies" has been proposed. On the basis of surveys at scales of 1:100,000 and 1:200,000, an evaluation of permafrost conditions is made, and the terrain sensitivity resulting from damage

66

to the vegetation cover, to excavation, and to the warming influence of buildings is evaluated. Optimum building methods are chosen, bearing in mind environmental protection measures (Baulin et ai. 1978).

Methods have been developed for making rapid engineering and geocryological surveys in oil- and gas- bearing areas and pipeline routes of northern West Siberia (Mel’nikov 1973, Mel’nikov et al. 1974). Most important is the landscape indicator method, which includes widespread application of aerial photography and topographic maps. An example of evaluating the territorial complexity of a gas pipeline route is presented in a graphic model of the gas line in relation to landscape features (Mel‘nikov et al. 1Y75). Compilation of the forecast mapping approaches for the regions of the Poluy-Nadym and Pur-Nadym in Western Siberia have been presented (Mel’nikov et al. 1978). Methods for interpretation and application of aerial and satellite photography, including spectrazonal photography, are being perfected (Gavrilov and Ershov 1977, Gavrilov et al. 1978, Eliseev 1977, Lynov e t a l . 1977).

kxper imen ta l app l i ca t i on of the rma l ae r ia l photography in permafrost regions produced promising results for mapping geocryological features (Cornyi and Shilin 1978).

An indicator-interpretive scheme has been compiled on the basis of research carried out in the northern taiga and forest-tundra landscapes of northern West Siberia. The scheme includes interpretive features for 1 6 terrain indicators and their corresponding geocryological conditions (Moskalenko 1975a).

Information received from permafrost surveys is used to define characteristics and conditions when perform- i n g q u a n t i t a t i v e f o r e c a s t i n g w h i c h i n c l u d e s mathematical and physical modeling. Mathematical models of thawing and freezing processes employ the Stefan solution. Computer modeling of this problem has been suggested and it has good prospects for solving multi-dimensional problems [Melamed and Medvedev 1974, Kudriavtsev 1974). Kudriavtsev has derived a formula for heat circulation within the layer of annual temperature fluctuation which takes into account phase transitions of water during seasonal freezing, It is based on the annual temperature at the bottom of the freeze- thaw layer, and the composition and moisture content of the soil (Melamed 1978). G.M. Fel’dman has proposed solutions that more closely approximate actual environmental conditions (Fel’dman 1973, 1977). Through experimental research, he derived the quantitative dependence of seasonal freeze-thaw depth, temperature of the frozen ground, and heat circulation in the ground on the combined parameters of air temperature and the composition and properties of the snow, vegetative cover and ground (Fel’dman 1977). Thermal conductivity of tundra cover in its natural and disturbed states ha5 been researched by Mandarov and Skriabin (1978). Similar quantitative relationships have been published for Western Siberia (Grechishchev ct a l . 197.5).

A model has been proposed for calculating ground temperature and summer thaw depth in relation to

changes in heat balance of the diurnal surface conditions; this model permits one to study the influence of the meteorological regime on geocryological conditions (Palagin and Natanzow 1975). A model and algorithm have been developed for determining the quantitative influence of vegetation and snow cover disturbances on the depth of seasonal thaw, and on ground temperature in the BAM zone (Pal’kin 1975). Analytical solutions have been derived for areas disturbed during road construction (Savko 1978). For the BAM zone forecast estimates or calculations have been made using a statistical model and 1-2 dimensional calculation scheme for heat exchange in soils (Tutkevich and Corod- nova 1977). A solution to the Stefan problem is given in order to choose a method for thermal amelioration of frozen ground (Smorygin and Fandew 1977).

Analytical solutions are available for predicting the results of cryogenic processes: reworking of shores of lakes and reservoirs (Balobaev and Shastkevich 1974, Cogolev 1977, Savko 1977, Tomirdiaro and Riabchuk 1974), icings or naled’ (Sokolov 1977), slope processes (Kudriavtsev et al. 1977, Chubarova and Lavrent’eva 1977) and thermokarst (Fel’dman 1977, Shur 1977).

In contrast to the existing solutions to the problem of ground freezing under a snow cover, a different method of solving the problem has been proposed; i t takes into account the dependency of the thermal conductivity of snow on temperature. A computer program has been developed for three- and four-layered media using the EVM-”222 computer (Shipitsina 1978). Solutions t o problems concerned with the temperature field of frozen ground around mines and mine shafts have been studied and calculations have been made (Fedorov 1976).

Critical changes of parameters of such systems as soil-frolen ground and thawed ground-groundwater due to industrial development of the territory, and catastrophic changes due to disturbance of the natural environment, have been studied from the thermophysical aspect (Khrustalev 1975).

Physical modeling using electro- and hydrointegrators is being widely implemented in forecasting. This type of modeling has been used for environmental protection purposes i n one of West Siberia’s regions to evaluate methods for improving water quality (Novikov 1977) and to determine the influence of surface cover and topography on the freezing and thawing of the ground (Ershov 1971a, b, Ershov et al. 1978).

Techniques for evaluating terrain sensitivity to technological impact are being developed. It has been suggested that terrain sensitivity should be estimated on engineering-geological maps (Demidiuk 1977), landform- permafrost maps (Lynov et ai. 1977), ice-content maps (Lur’e 1977), and on regionalization maps according to type and intensity of thermokarst, thermal erosion and frost heaving (Chizhov et al. 1977, Smirnov et al. 1975, Stepanov 1977). Systematic photogeological mapping of the territories under development is in progress (Eliseev 1977).

67

It is recommended that estimates of rates of cryogenic process development and landscape changes be made, and that the effectiveness of environmental protection measures in regions of planned pipeline routes be evaluated. Pipeline route conditions are considered under two different categories: 1) complex, where there is frozen ground, and the temperature of the discontinuous permafrost is high, and 2) simple, where ice content is low and the temperature of the permafrost is low (Baulin et al. 1978). L.N. Maksimova (1977a) has presented the fo l lowing c lassi f icat ion for the engineering-geological evaluation of permafrost areas under development:

1. Regions where development disturbs permafrost conditions and ecological systems, and irreversible cryogenic processes are set into motion, disturbing existing landforms.

2 . Regions where development does not cause catastrophic changes in landscape, and where it is possible to partially reestablish natural processes, through natural or artificial means.

3. Regions where changes in permafrost conditions lead to favorable changes in the geological environment.

4. Regions where changes in permafrost conditions have practically no effect on the geological environment.

A ten-point scale of probability for activating cryogenic processes as a result of changes in surface heat balance resulting from territorial development is suggested. However, factual observations necessary for developing this sensitivity scale are insufficient at present (Shur 1977).

A territorial evaluation has been made according to the degree of complexity of engineering undertakings needed to improve permafrost-engineering-geological conditions (Gavrilov et al. 1978). Three categories have been designated:

1. Those conditions that do not need complex measures,

2 . Those requiring complex measures. 3. Those which require extremely complex measures.

PROTECTION OF TERRAIN DURING DEVELOPMENT

The main protection measures emphasize prevention of the thawing of permafrost. These measures include thermal and hydro amelioration of soils, biological recultivation where the surface was disturbed during development, and other measures for specific types of developmental activity such as mining, landfill and agricultural development.

Methods have been proposed for ground heat amelioration, control of ice sublimation and desublimation in frozen soils by means of changes in gas medium parameters, and controlled changes on the surface of ground masses (organic film, surface coating) (Ershov e t al. 1974, 1978).

Practical measures for environmental protection have been developed during the construction and operation of trunk pipelines, mostly in Western Siberia. En- vironmental protection measures must adhere to the following requirements: excavation and pipelaying operations should be carried out during the period of stable negative air temperatures; tree stump and root removal is prohibited in areas of high ice content; traffic is possible only with maximum maintenance of the vegetative and soil covers and without disturbance of the soil surface on the right-of-way (Bol‘shakov 1975, lvanov and Friman 1975, Mikhailovskii and Lolua 1975, Serdiukova and Vnukov 1975, Serdiukova e t al. 1975). The use of natural and artificial insulating materials i s recommended for covering areas that have been de- nuded of vegetation or soil cover and leveled during construction (Mikhailov 1975). Complex areas requiring costly environmental work and materials are best avoided during pipe-laying due to economic considerations (Sukhodol’skii 1975). During road construction, apart from the above-mentioned measures, it is recornmended that fill be placed over the natural vegetation and organic layer or onto artificial thermo-insulation (syn- thetics, peat, slag, wood flooring). It is desirable to paint the fill surface white (Bol’shakov 1975, Kaganovskaia 1975).

Special techniques and technology are recornmended during mining activity such as excavating the producing strata and reinforcing the roofing of galleries and shafts. To prevent surface subsidence over mine shafts it is recommended to use short-face systems (of mining) and to plug the worked-out sections (Fedorov 1976, Krylov et al. 1975, Sever’ianov et al. 1975).

Areas with near-surface, ice-rich soils are considered to be entirely unsuitable for agricultural development within the taiga region if they require uprooting of trees and plowing. Apart from bog formation that may take place, the surface that has been cleared of trees and plowed becomes hummocky as a result of uneven subsidence. Drainage can be introduced where more homogeneous subsidence due to thaw occurs (Vidiunina and Khudiakov 1974). However, drainage is not always effective in cold climate and permafrost areas. Wide experience with drainage and flushing of saline soils has been gained in Central Yakutia (Elovskaia et al. 1977b).

In order to control permafrost conditions in agricultural areas s o that cryogenic process development may be avoided and to increase soil fertility, thermal and water amelioration techniques are introduced. Significant amongst these are snow enhancement techniques, which, depending on the conditions, either allow thawing of the underlying permafrost or prevent new permafrost aggradation and pereletok formation. The regulation of snow cover in West Siberia serves as a basis for modifying the temperature regime and freezing and thawing of the soils. Recommendations have been developed for snow retention in fields and a system of techniques for thermal improvement of areas with varying natural conditions has been developed in West Siberia (Tshigir e t al. 1977).

Table 3. Depth (meters) of seasonal thaw of sandy loam in Yakutia, under various surface modifications (modified from Pavlov 1978a, b).

Type of cover 1972 1973 1974 1975 1976

Natural 1.89 1 99 1 . 8 0 1 85 1.83

Wooden paneling 1 . 7 5 1.78 - - -

Wooden panel and foam - - 0.64 0.73 0.63 insulation layer (1 cm)

Foam insulation (7 cm) 1.01 1 09 0.97 1.00 - Foam insulation (20 cm) - 0.42 0.35 0.39 - Foam insulation (30 crn) - - - - 0.26

A scheme for land reclarnatlon o f Far Northern regions has heen developed that holds promise for the future. It Includes techniques of drying, irrigdtlon, erosion control, and rultivation among others (Kriuchkov 1977).

Irrigation and drainage tochniqucs for agricultural land in the permafrost rone are treatod it1 numerous papers (Hogushevskii 1977, [lovskdla et a1 .1977a, Gavril 'ev and Mandarov 1076, Kamrnski i 1976, Kriuchkov 1Y77, Lomakln et al. 1977). Other papers deal with artificial surface cover for purposes of temperature regime corltrol and regulating of the thdwing and freezing of soils I n the permafrost regtons (Demchenko 1978, Pavlnv 197Ha, Kashkin and Shuvdlov .1970, Skriabin -1976, Srr~orygin and Vediaev 1977, Sr-norygin et ai. 1978).

Several synthetic. and na(urdl material\ have heen tested for protecting soil frnrn thaw I.ong-terrn research in Yakutia and in the northern Tyurnen has Indicated that fodtn insulation has high insulating properties compared t o other materials, particularly wood paneling (Tahlr 3 ) . The relationship o f thaw depths twneath foam insulation covering of varying thickness and under natural conditions was presented and a formula was suggested for the correspondlrlg calculation (Pavlov 1978a, b). An approximate method for calculafirlg ground thaw dynamics under the insulating layer has been developed using the EVM "222 and different cotnbtnation5 of insulating layer properties and ground and arnbient conditions (Demchenko 1978).

The effectiveness of a water-air foam as a heat in- sulator i s being investigated (Smorygin et at. 1978). Syn thetic transparent film i s used to increase thawing of frozen soils. A model has been developed which will allow one to compute the ratios of thaw and freeze depth under various plastic film covers in order to determine the optimal time span required to cover the ground and to define how soils will thaw under the film as a result of changes in solar radiation. For more practical application, graphs and charts have been developed (Smorygin and Vediaev 1977). Field observations have shown that the film coverings raise ground temperature by 4 t o 4.S0C, speed up the date of onset of thaw by 15 to 20 days, and increase the depth of summer thaw by 0.5 to 1.5 m (Rashkin and Shuvalov 1970, Skriabin 1976).

One of the measure's used to restore the disturbances caused during development of territories i s the rccultiva- tion of vegetation and restoration of terrain. . I hese measures are not only of technical consideration-slope stabiliration and recovery of vegetation t o favorably affect the ground thermal regime--but are also of aesthe- tic importance Difficulties of recultivation are, to a great extent, assoriated with the very slow natural recovery process of vvgetation in the North.

Moss-lichen cover damaged by reindeer rnovement or destroyed by man is restored only after several decades. Partial meadow formation in drnuded sites i s arrested after a few years as a result o f increased moss and shrub growth and bog formation (Kriuchkov 1977, Vital'1975). Suc-h phenomena have been ohserved in the tundra on the bottom of lake basins which have been drained in order to induce meadow formation (Tornirdiarov 197.5). In Chukotka, the slow and partlal regrowth of grasses on drained basins started to slow down after seven years because of moss growth and permafrost aggradation (Tatarchenkov 1977).

In northern West Siberia grass-moss bogs are the more quickly rejuvenated areas; i t is here that bog formation increases when surface cover i s disturked. Shrub-lichen c;ommunitlcs of flat peatlands are more slowly restored. Where soil cover is maintained, cloudberries, Ledurn and cottongrass will grow back within 3 or 4 ycars. In cases where the peat layer i s damaged and thertnokarst depressions appear, grass- moss communities will develop. Vegetation, practically speaking, does not regrow on forest-covcred hillocks and ridges underlain by frozen rands following the removal of the forest shrubs and peaty horiron. In order to accelerate and maintain growth of the re<-oloniring vegetation, special agrotherrnal techniques are applied (Bol'shakov 1975, lvanov and Frirnan 1975, Liverovskaia 1975, Mikhailovskii and Lolua 1975, Serdiukova and Vnukov 1975, Serdiukova et al. 1975). In addition, problems of recultivation of human-impacted landscapes have been investigated (Kolesnikov 1974, Potemkin 1975, Razurnovskii 1975, Stnolianitskii 1976, Shcher- batenko and Kandrashin 1977 and Trofirnov 1974).

A regional scheme has been developed for recultivation of impacted areas of Siberia and the tar East. Each zone is characterized by a description of its type of irn- pacted terrain and the type of recultivation to be performed (Kagim-Zade and Trofimov 1977). On the basis of investigations into human impact on the natural complexes of Siberia, studies on the resistance t o various levels of disturbance, and their influence on ecological conditions of human life, environmental protection programs have been developed, including recultivation. The optimal scheduling of work has also been considered (Ragin-Zade and Trofimov 1977).

In summary it is possible to classify human-induced terrain disturbance according to type and cause (Shur 1977, Smirnov et at. 1975, Trush and Chirhov 1977). These types, causes, sensitivities, and recommendations for environmental protection and recovery are presented in Table 4.

69

Table 4. Main types of human-induced terrain disturbances in permafrost regions of USSR, their causes and probable consequences, and general recommendations for environmental protection measures, depending on the surface sensitivity and type of disturbance ( I , 2, 3). Based on N.A. Grave (in Cerasimov, in press).

Probable consequences of disturbance Recommended measures for

Type of disturbance Causes of disturbance [according to region's sensitivity] environmental protecjion

I: Compaction and damage to vegetative cover.

Movement of heavy vehicles, partlcularly In summer; intensive reindeer pasturing; light construction activlties.

1 Development of thermokarst- eri5ded relief with "sunken" lake depressions and gullies. 'Thermal abrasion of shorelines

2 Appearance of boggy deprcs- slons and eroded ditches withln boundaries of dlsturbancc.

3 Appearance of small boggy de- presssions and nround slump-

( I ) Limitation and regulation of vehicle movement and reindeer grazing; improvement of drainage; f i l l ing of upper reaches of gullles; therm* insulation of surface cover, re. cultivation

(2) Regulhtion of vchlcle movement and reindeer grazing; re- cultlvation.

(3) Kecultivation

I I : Destruction of vegetation cover; fell ing and removal of trees.

Intensive movetnent of heavy vehicles, especially in summer, drilling and exploratlon.of deep wells; preparing right-of-ways for "linear" construction; fires.

Ill: Destruction of plant and soil covers, includlng peat lands; removal of tree stumps; exposure of mineral soil.

IV: Excavating and stockpiling of soil and sediment; placement of embankments and pads.

Intensive constructlon, surface grading; clearing for agricultural use

Intensive constructlon, surface grading; drainage and irrigation ditcher; open-pit mining, dredging In rlvers

ing, restrlctcd to area disturbed.

see 1-1

In taiga regions of central Ydkutia thermokarst 5ubsidcnce within boundarlcs of damage Kock streams and solifluctlon devclopmPnt on slopes In- (-reased ground frce71ng, frost heaving and rrack formdtion of s o i l without therrnokarst

See 1-1

3 Bog formation, appearance dnd increased development of so l i - f luct ion and rock streams on \lopes.

1 SPP 1-1

(1 ) Scc 1(1]

(2) Insulation of cover; rccultiva- tlon.

(3) Irnprovernent of dralnage, re cultivation

(1) Scr l(1); wlnter work prcfcr- dble, main constructlon should take pldcc I n wlnter and early spring when cledrlng forest for agrlrultural purposes, avoid- ance of areas nf ground Ice oc(urrence, local thermal In- ~u lc l t lon, dralnage, recultlva- tlon

( 3 ) See I l(3)

(1) Set, Ill(1); placement of f i l l over vegetatlon cover, Install,l- tlon of drtlficial thermo- Insulation layer; drainagc rys, ten1 for adjacrnt arecar

70

Table 4 (cont’d). Main types of human-induced terrain disturbances in permafrost regions of USSR, their causes and probable consequences, and general recommendations for environmental protection measures, depending on the surface sensitivity and type of disturbance (1, 2, 3) Based on N.A. Grave (in Cerasimov, in press).

Probable consequences of disturbance Recommended measwes for

Type of disturbance Causes of disturbance (according to region’s sensitivity], environmental protection

2 See 1-1 (2) Drainage and recultwation

3 Bog formation between dredge (j) I f possible, quick reclamation; piles on finc-gralned soils covering with organic layer

In southern reglons of permafrost increased frcezlng of walls and trench hottoms and d1tche5 and permafrost forms if no water present. Development of heaving.

V: Destruction of min- Underground mining of 1 See IV-1; subsldence, deep (1) Use of shallow-minlng systems era1 rock masses minerals; pumping of cave-ins of surf<lce ovcrlylng with refilling of mined space with partial removal water and hydro- mines. of ore, including carbons. pumping of water, 2 See IV-2, subsidence; (2) Special measures for rein- oil, gas cave-inr of 5urfat-t forc.ing celllngs of mines and

back-filling

3 See IV-3, i r l some cdses possible (3) Under certain conditions in- cave-in5 and subsdenre duc to duced or forced cold alr In thaw in mine celllng, possible sh,lft; recultivatlon and sur- also to increase freer lng of CPII- face and ground water draining and walls of mlne to In- age. creasr stablllty strength

1 Region of extreme srnsltivity: lntenslve processes of thermokarst, thermal erosion forrnlng “sunken” ldkes and gul l~cs re5ultlng from outside the llmlts of the slightest surfacc disturbance.

Not so Intensive; dlsturbances remaining wlthln the boundar~es of thc sllghte9t Wrface disturbance5

Weak subsidence with formatlon of hogs and slope movement pht~r\onwna wlthlr) the area of dlsturbance

2 Region of average sensitivity:

3 Keglon of low sensitivity:

CONCLUSIONS AND RECOMMENDATIONS

A large number of observations on the response of years and greater incidence o f slope failure. permafrost terrain to human-related *activities and Human-induced disturbances arc limited to specific natural processes have been reported. The majority of areas of construction or urban areas and linear transpor- the North American investigations were undertaken in tation routes. The intensity and time of disturbance and the Mackenzie Valley and a lesser number in the Arctic terrain properties control the response of the terrain to Islands and Alaska. Computer modeling of natural and disturbance. Disturbances resulting from summer ac- impact processes and related field measurements are tivities have greater physical and visual impacts than providing insight into the relationships of coupled activities occurring in the wintcr. Most disturbances moisture and heat flow. Approaches to terrain sensitivity caused by surface activities in the summer are no longer analyses have been undertaken and partially evaluated. permitted due to restrictions of access. However, past

Active, natural processes occur primarily in the curn- disturbances are still activc and provide useful informa- mer and provide useful indicators o f potential terrain tion on questions of long-term stability and recovery hazards. These include therrnokarst and thcrrnal and Off-road vehicle traffic on low pressure or air cushion hydraulic erosion processes on permafrost terrain cnn- tires in the summer produces some immediate visual im- taining largc quantities o f ground ice and river bank ero- pact and considerably less thermal or physical (jistur- sion and soil slumping and flows on steeper terrain, Fire bance compared to more conventional tracked vchicles. as a natural agent of thermal dlsturbance generally Spillage of hydroc-arbons on permafrost terrain seems results in thickening of the active layer over a nurnher of not to cause major thermal disruption; howevcr, the

71

saturated soils and the underlying impermeable permafrost may facilitate movement of the oil downslope and thereby increase the area of impact.

Observations on natural and disturbed active layer thicknesses, thermokarst features, ice wedges, and mass movements are leading to a better understanding and predictive capability of the geographic consequences of disturbance. Response to disturbance by active layer thickening is greater in the warmer discontinuous permafrost zone compared to the colder conditions that exist, for instance, in the Arctic Islands. The use of terrain disturbance as an indicator of climatic change has much to offer. For instance, deterioration of the permafrost at its southern boundary is obvious from the appearance of thermokarst features. Activity and stratigraphy of ice wedges and other ground patterns provide more subtle indications of change.

Some recommendations for continued research are: 1. Continue observations on past disturbances in order

to establish the time required to reach the maximum level of disturbance and rate of recovery.

2. Continue development and field testing of terrain sensitivity mapping at several scales and compare approaches and synthesize results between North America and the USSR.

3 . Undertake comprehensive geomorphic and regional geothermal investigations for purposes of establishing the stability of permafrost conditions under natural, climatic change. 4. Continue the development of computer modeling

of coupled heat-moisture flow and field validation in order to anticipate the results of human and natural activities.

5. Establish long-term monitoring observations t o con- f i rm or invalidate prior environmental assessments and impact prediction of large engineering projects such as dams, pipelines, and highways (National Academy of Sciences 1975).

h . Continue research to develop improved methods and guidelines of environmental protection and reytora- tion of permafrost terrain.

ACKNOWLEDGMENTS

Portions of this review paper were prepared under the Corps of Engineers project at CRREL entitled ”Cold Regions Environmental Factors.” Mrs. Martha Andrews, Boulder, Colorado, assisted in the initial bibliographic compilation (Andrews 1978). Dr. V.N. Andrew, Biological Institute, Yakutsk, assisted in portions of the Soviet bibliographic compilation. Dr. Samuel Outcalt, University of Michigan, assisted in early phases of the modeling and thermal regime compilation as did Dr. A.V. Pavlov, Permafrost Institute, Yakutsk, on heat balance literature. Dr. Boris Vtiurin, Institute of Geography, Academy of Sciences of the USSR, Moscow,

provided assistance on the Soviet mapping discussion. Mrs. Natalie Voshinin, U.S. Library of Congress Cold Regions Bibliographic Project, translated and cross- indexed the Soviet citations. M s . Valentinia Paganuzzi, Canada, assisted in translation of the Soviet text. Mr. Stephen Bowen, CRREL, provided editorial assistance. The paper was prepared as a contribution to the joint U.S.-USSR Environment Protection Agreement on the Protection of Northern Ecosystems (Scriabine 1978). Dr. George Swinzow provided valuable advice and assistance in the review of the Soviet section of the paper.

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ABELE, C. 1976. Effects of Hovercraft, wheeled and tracked vehicle traffic on tundra. Proceedings of the Sixteenth Muskeg Research Conference, National Kesearch Coun- cil of Canada, Associate Committee on Geotechnical ResearchTechnical Memol l6, pp.186-215.

ABELE, C. and j . Brown. 1976. Arctic transportation: Opera- tional and environmental evaluation of an air cushion vehicle in northern Alaska. American Society of Mechanical Engineers, ASME Paper No. 76-Pet-41, Jour- nal of Pressure Vessel Technology, pp. 1-7.

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ADAM, K . M . and H. Hernandez. 1977. Snow and ice roads: Ability to support traffic and effects on vegetation Arc- tic 30(1), pp. 13-27.

ADDISON, P.A. 1975. Plant and surface responses to environmental conditions In the western hlgh arctic. In Plant and Surface Responses to Environmental Condi- tions in the Western High Arctic (L.C. Bliss, Ed.). Arct ic Land Use Research 74-75-73, Department of Indian Af- fairs and Northern Development, Ottawa, pp. 3-20.

7 2

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AMERICAN GEOPHYSICAL UNION. 1976 Procepdings Sec- H t R L , R., J . Brown ,Ind R. tiaugerr. 1978 lhaw penetration ond Conference on So11 Water Problems 111 Cold Regions, and permafrost conditions associated with the Edmonton, Alberta, Canada. 1-2 September 1Y76, Spon- 1.ivengood to Prudhoe Bay r o d , Alaska. Proceedings sorcd by Special Task torce of the Division of Hydrology Third International Conference on Permafrost, Vol. 1, (University of California, Davis), 185 p National Research Council of Cdnada, pp. hl5-621,

ANDKEWS, M. 1978. Selectcd bibliography of di3turbance and restoration of soils and vegetatlon In permafrost regions of the USSR (1970-1'377). CKREL Special Report 78-1Y, 175 11,

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KOMANOVSKII, N.N. 1978b. Cryogenic geological processes and phenomena. In General Ceocryology (V.A. Kudriavtsev, Ed.). Moscow State University, Chap. VII, pp. 231-282 (32.4073).

KOMANOVSKII, N.N. ,and M.O. Leibman. 1975. Regularities governing thermal regime of rocks beneath active layer, in relation to frost fracturing. Transactions, Industrial and Scientific Research Institute for Engineering Surveys in Construction, Vol. 36, pp. 91-99.

PODBORNYI, E.E. 1978. Probability approach to frost crack

85

SAVKO, N.F. 1978. Foreqasting changes in permafrost- engineering-geological conditions during road construction. In Methods of Engineering-Geological Investiga- tions of Permafrost Areas; Collect ion of Works (N.I. Trush and V.A. Volgina, Ed.). Permafrost Institute, USSR Academy of Sciences, Yakutsk, pp. 123-132 (33-0520).

SERDIUKOVA, V.V. and V.K. Vnukov. 1975. Unfavorable geocryological phenomena observed along the routes of the Yakutsk gasline complex. All-Union Conference on Environmental Protection in Kelation to Economic Development of Permafrost Regions, 27-29 October 1975 (P.I. Mel‘nikov Ed.). Moscow, pp. 10Y-110 (CRREL Dra f t Translation 518) (30-4203).

SERDIUKOVA, V.V., V.K. Vnukov and V.V. Shamsotinov. 1975. Designing main pipelines for permafrost with a high total ice content. Al l-Union Conference on tnvironmental Protect ion in Kelat ion to Economic Development of Permafrost Regions, 27-29 October 1975 (P.I. Mel’nikov, Ed.). Moscow. pp. 112-114 (UKREL Draft Translation 518) (30-4203).

SERCEEV, B.P. and P.N. Skriabin. 1978. Radiation regime of vakious types of active surfaces In the northern Krasnoyarsk territory and Tyurnen’ region. In Ceother- rnophysical Investigations in Siberia; Collectlon of Works (A.V. Pavlov,Fd.). Nauka, Novosibirsk. pp 47-58 (32-321 2) .

SEVER’IANOV, A.N , S . I . Nernchi lov and V.P. Pclrov. .1975. tnvironmental protection in coal-mining parts of the per- tnafro5t zone. All-Unlori Conference on tnvironmental Protection In Relat ion to I-conomlc Development of Per- trlafrvst Regions, 27-29 October 1975 ( P , l Mel’nikov. Id . ) . Moscow, pp 94-0h [CKREL Draft Translat ion 518) (30-4203).

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SHILOVA, 1 . 1 drid S.A Mamacv .1977. Kcvegetation of disturbed sandy soils in 011 product ion areas of the ccn- tral Ob’ region. I n Lclnd Kecldrrlation in the Far North, Ko lo~ , Moscow pp. 2 l5 -242 (32.5139).

SHIPITSINA, L I. -1978. Differential method of solvlrlg thr proklern of ground f rcr l lng undcr snow al lowing tor the dependcnce o f snow conrlurt lvi ty on temperalure In Ct‘otherrnophysical Investigations In Slbcrl;l; Collcctlon o f Works (A.V. Pavlov, F d ) , Nauk3, Novoslbmk, pl). 8Y-YFI (32-321 7).

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SMIRNOV, V.V., V.P Marakhtanov, I. T . Llverovskala, T.I. Smlrnova and A.A. Vltal‘. 1975. Englneerlng 5tandards for earthwork usrd in the construction of pipcllnes dnd consequent d isturbances of natural environment (vegetation, soils, surface layer5 of ground). All-Union Conference on Environmental Protcctlon in Relation to Econorrilc Developmcnl of Pertriairost Regions, 27-29 October 1975 ( P , l . Mel’nikov. L:d ). Moscow, pp. 77-78 (CRREL Draft Translat ion 518) (30-4203).

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ZAHOLOINIK, S N lY7R i3ynarnic:s of temperature fields in seasonally and pererlnlally irorerl rocks during thr disturbancr of surtaccl covers in Central Yakutla. General Ceocryology, Thlrtl I r l t c m d t i o n d l Conf r r rn rc on I’errndirost, Kcporfs, Vol .I, Nauka, Novosibirsk, p p 21 0-2.1 4 (33-2600)

ZAMOLOTCHIKOVA, 5.A dnd V N Smlrnova 1Y74 lemper- aturc and seasonal thawing of rocks In the Lend Vilyuy interfluve. Pcrlndfrost Invcstigntlons, Most:ow St;+te Unlversity. Vol .14. pp 14.1-.147 (29-23.10)

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ZI1IC;AKI V, L.A. 197Sb. Processes of Thermal Derluddtion and t he De io r tna tm o f Thdwing (;round N‘wka. MOSCOW, . lOY p. (:JO-.34hO)

87

APPENDIX I: SYNOPSIS OF TEMPERATURE LITERATURE ON LAND-BASED AND SUBSEA PERMAFROST, MICROCLIMATE AND ENERGY BALANCE, AND RELATED MODELING LITERATURE

Brown (1975)

Brown (1977)

Land-Based Permafrost (Non-alpine)

Judge (1977)

Barsch (1978) ,Ind Haeberll Alps (1 Y 78)

Fujii (1978)

Fujii and Higuchi (197h) Himalayas

land-Based Permafrost (Alpine)

Ferrnatrost 1s contlnuous above 3500 nl, whlch IS equivalent to a medt l drlnucll temperature of - 8 5 O C ; the lower limit of actlve rock glacler I S -Z°C MAT

Northern Hemlspherp 1)lstrlbutlon of dlplne permafrost i s given and total dred estltrrated at 2 3 x I()‘, km’. l-hls occurrence of alpine permafrost is related to the coldest and warmest months’ mean tcmperdture

Permafrost occurs above 4900-5000 m .

88

Corhunov (1978)

Harm dnd Brown (1978)

Ives (1 974)

Woodcock (1 974)

Harrlson and Ostrrkamp (1 976)

Hunter et a i . (1Y7h)

J udge (1 974)

Lachenhruch and Marshall (1 977)

Lewellen (1977)

National Academy of Sciences (1Y76)

Osterkamp ,Ind Hdrrisori (1 977)

Raj and Judgc (1Y77)

Barrow, Alaska

North America

89

Reference Locatiorl Synopsis

Addison (1 975)

Beattie et a l (1973)

Courtin and Lahlnc (1977)

Crdy et a 1 (1Y74)

Cuymorl (1375, 1970)

Microclimate and Energy Balance

Queen Ellzabeth Islc3nd, Mirrocnvlronment, energy and water regimes of both natural Canada and disturbed surfaccs of two plant cotnrnunitles were deter-

nllrled

1 ununuk, Canada Energy budgets over dlsturbrd and undlsturbed terrain and their relation to the Muskeg Kesearch Institute terraln disturbance c.lasslfication system are evaluated.

Devon Island, Canada The descrlptlve microclimatology dnd an evaluation of the encrgy inputs are givcn based on data from 12 sites on the Truelove Lowlands and adjacent platcau.

1 uktoyaktuk, ( :an~dd Melthods to evaluate the energy budgets were developed and data are glven for dlfferent levels of disturbance.

Ilarrow 3nd Falrbankr. AI<>sk<l Fleld mcasurernents of soil molsture. uressure and temperature

( -

-I

LeDrew (1Y75)

Mdykut and Church (1371)

Nlcholson (1Y70. 1978d)

Ohmura and Muller (1 976, 1977)

Rouse (1975)

KydGn (1978)

1974a)

111741~)

97h)

Reference

90

Location Synopsis

Skartveit e i al. (1975)

Smith (1975)

Microclimate and Energy Balance (cont’d)

Fennoscandia Energy flow, microclimatic and climatic components at three arctic and subarctic sites are summarized.

Canada

Weller and Holmgren (1974) Barrow, Alaska

Abbey et al. (1978)

Arnold (1978)

Significant differences in thermal regime exist under various vegetation types; mean annual ground temperature decreases with increasing vegetation.

The microclimate is described and daily heat components computed and summarized by periods throughout the year.

Modeling txc-1udt.s pipcllne and other construction-related rnodellng

Tuktoyaktuk, Canada Two index models for predicting ground heat flux during the thawing period are presented and verified; one is based on cumulative heat radiation and the other on cumulative air temperatures.

Non-site-speciflc

Atwater and Pandolfo (1975) Barrow, Alaska

Coodrich (1978) Non-sitf’-\perific.

Coodwifl (1976) Barrow, Alaska

Coodwin and Outcalt (1974) Canada

Coodwin and Outcalt (1975) Barrow, Alaska

Cuymon and Luthin (1974) Non-site-speclfic

Lord et al. (1974) ,Barrow, Alaska

Lunardini (1978) Non-site-spccific

McCaw et al. (1978)

McRoberts (1975)

Barrow, Alaska

Non-site-specific

A model is described for estimating ground surface temperatures based on relative humidity and point temperature.

The relatlve magnitude of thermal modification and moisture changes due to towns in tundra are simulated.

Non-linear effects associated with temperature-dependent soil thermal conductivity and soil latent heat can significantly affect the snow-ground temperature interaction.

Summer soil temperatures on several microrelief elements were obtained and the sensitivity of diurnal near-surface thermal reglmes to spatial variability in surface conditions is explored through development and use of models of the surface energy balance.

The effect of organic layer removal and drying of the soil surface upon active layer thicknes is simulated; wetness is more sensitive than peat removal in the model.

A digital computer model simulates the annual evolution of the thermal regime in the snow cover and active layer.

A one-dimensional coupled heat and moisture transport is developed

Interactions of thaw lakes and surrounding tundra are simulated by one- and three-dimensional models.

A theoretical equation for N-factor as a function of air index, seasonal surface heat transfer exclusive of convection, surface coefficient of convection, and soil thermal properties is developed.

Precise soil temperatures and measured thermal conductivity data for wet organic-rich soils are combined to calculate summer heat fluxes to a depth of 1 m.

Thawing under the natural active layer occurs according to the equation X = crft (X = depth of thaw, t is time, and u is a constant e x p r m d as cm/s%).

91

Reference Location 11"1"

Synops15 -"

Mil ler (1975) Modeling (cont'd)

Non-site-speciflc A surface heat balance simulator I S d?scrlbcd which c,ln be used to predict permafrost temperatures due to dlsturhancp m d to permafrost protertlvc schemes.

Ng and Miller (1975) Harrow, Alaska

Ng and Mil ler (1977) Barrow, Alaska

Outcalt et a1 (1975) Barrow, Alaska

Outcalt and Brown (1977) Fairhanks, Alaska

Outcalt and Carlson (1975) Non-site-specific

Sheppard, et al. (1978) Non-site-spec-iflc

Smith (1977) Eureka, Canada

Model structure and lnltlal validatmn of a tundr,l ~ a n o p y so11 temperature-thaw model are presented.

Calculated dlr and soil temperature agree wlthln lo(: of measured proflles and thaw 13 generally predlctpd wlthln 1 cm for an improved canopy-soil temperature model.

Snow ripening, melt, and dccumulatlon and actwe layer temperatures are simulated in conjunction with a rnow fence modlficatlon experiment.

The thermal modlfications of forest clearing, snow removal and accumulation and pavements are simulated

A simple surface climate simulator IS descrlbed which can be used to smulate the surface energy budget and 5011 thermal evolution.

Verification of coupled flow model using detailed labordtory and field experiments.

A model whlch simulates microclimatic and ground thertrlal regimes IS evaluated uslng ftcld data for a dry and wet slte. and the computer program and user's manual are presented

92

93

GEOPHYSICS IN THE STUDY OF PERMAFROST

W.3. Scot t ' , P.V. Sellmann' and J.A. Hunter '

Review Paper: Third International Conference on Permafrost , Edmonton, July 1978

1. INTRODUCTION

A. Scope

In this review of permafrost geophysical techniques emphasis is placed on methods tha t p e n e t r a t e i n t o t h e e a r t h to depths g rea t enough to provide information on permafrost propert ies or distribution. The emphasis is also on the North American l i terature and experience, because of t h e origin of the authors. A brief summary of cu r ren t Soviet experience has been prepared by Akimov et. al., (1979). The review covers the period s ince the Second Internat ional Conference held in the Soviet Union in 1973, although in a f ew cases t h e per iod was extended to es tabl ish his tor ia l perspect ive. The discussion includes investigations made on land and off shore, based on surface and airborne observations.

The reason for interest in geophysical explorat ion techniques in permafrost regions is obvious. As northern regions are developed we are continually reminded of the unpredic tab le na ture of ground ice and permafrost d is t r ibut ion, the consequence of inadequate subsurface data , and the high cost of dril l ing even at large interhole spacings.

As a resu l t of the need for methods to supple- ment dri l l ing observations and to provide less expensive means of rapidly obtaining subsurface data, geophysical methods have seen increased application in research and problem-solving studies in permafrost regions. This has included studies associated with the large pipeline programs in both Alaska and Canada. A new emphasis in commercial geophysical equipment development is also apparent , d i rec ted at acquiring shal low subsurface data to f i l l the needs of geologists and engineers.

Two processes are involved in the interpretat ion of data f rom geophys ica l measurements in permafros t terrain. The f i rs t is the der ivat ion of the geophysical cha rac t e r of the ground (for example, distribution of resist ivity or veloc i ty va lues) f rom the raw da ta . The second is the determination of the re la t ionship between these geophysical propert ies and the permafrost condi t ions which prevai l . Some of t h e geophysical techniques considered in this paper have relat ively wel l developed interpretat ion schemes and therefore the i r u t i l i ty res t s on the re la t ionship between the observed geophysical parameters and the permafros t p roper t ies of interest . Other techniques are l imited by interpretat ion procedures which are currently relatively undeveloped.

The appl icat ion of almost al l geophysical methods to problem-solving in permafrost regions is linked to the change in the phys ica l p roper t ies of e a r t h mater ia l assoc ia ted wi th f reez ing of incorportcd water , and formation of varying amounts of incorporated ice. The degree of change in the physical propert ies depends on moisture content , pore s ize , pore water chemistry, ground temperature , and pressure on the mater ia l . Some of these var iab les can have a s ignif icant inf luence on the propert ies by cont ro l l ing the t empera ture a t which f reez ing can occur and the amount of ice associated with a material . This is true, for example, in marine sed iments where pore water can have a high salt concentration, and in f ine-grained soils such as c l ay t h a t can have high unfrozen water contents due to t h e in te r fac ia l in te rac t ion tha t occurs be tween the mineral matrix and water (Anderson and Morgenstcrn, 1973). For th i s reason the parameters detected by most geophysical methods in permafrost dis t r ibut ion s tudies may not correlate exact ly with permafrost d is t r ibut ion as indicated by t empera tu re alone.

Therefore i t i s necessary to understand what propert ies are being measured during geophysical investigations in order to an t ic ipa te any d i f fe rences tha t may ex is t be tween permafros t l imi t s ind ica ted by the var ious techniques. Fortunately, in most cases t h e significant changes in proper t ies of t h e e a r t h to which the var ious geophysical techniques are sensi t ive occur a t temperatures only sl ightly lower than 0°C. The fol lowing sect ion discusses the parameters determined by the geophysical methods covered in this review, and their dependence on f reez ing of incorporated water .

B. Relevant Geophysical Parameters

Observat ions made by electr ical and e lectromagnet ic techniques at exci ta t ion f requencies below 100 kHz are sensit ive primarily to the res is t ivi ty of materials. Figure I , based on Hoekstra and McNeill (1973) and Olhoeft (1978) shows the var ia t ion in res i s t iv i ty wi th t empera ture for some mater ia ls and i l lus t ra tcs the genera l increase in res i s t iv i ty tha t normally occurs with freezing. The techniques that ope ra t e a t f requencies above 100 kHz are in f luenced by both resist ivity and relative permitt ivity (dielectric constant) (Katsube et al., 1976). High-frequency laboratory measurements made by Annan and Davis (1978) i l lus t ra te the dependence of re la t ive permi t t iv i ty on t empera tu re fo r a clay soil (F igure 2). Additional data showing changes in re la t ive permi t t iv i ty and loss tangent with f reezing of t h e

'Resource Geophysics and Geochemistry Division, Geological Survey of Canada, Ottawa, Ontar io .

'IJ.S. Army Cold Regions Research and Engineering Laboratory, Hanover, N,H.

94

ground are available from studies reported on in the proceedings of this conference by Rossiter et al., (1978). Their data, obtained from field measurements, show a noticeable decrease in loss tangent and relative permittivity with seasonal f reezing of the act ive layer .

Biotite Granite 0.1 %water

saturated Sand Gravel ----------"

Fairbanks Silt

c lay

I IO

1:i 0 0 J 2 I 1 I 1 I I I 243 253 263 273 283 293

b TEMPERATURE ( O K 1

Figure 1. Variations in resistivity with temperature f o r some material types. (a) a f ter Hoekstra and McNeill (1973), and ( b ) a f t e r Olhoeft (1978) .

The seismo-acoustic techniques all rely on changes in the compressional and shear wave velocities of rocks and soils which normally occur with freezing. These changes can be as dramatic as those that occur in the e lectr ical propert ies of most earth materials. This change in velocity with freezing is discussed by Pandit and King (1978), whose measurements were made a t acoustic frequencies on rocks with varying pore-water salinity. Figure 3, which shows changes in veloci ty with temperature for several material types, i s based on the studies done by Aptikaev (1964). Studies of compressional wave velocities conducted by Stevens (1973) and others indicate compressional velocit ies of around 3100 m/s for silt-sized material a t around -4.O"C. The velocit ies were similar to field measurements obtained by Hunter (1973a) for i ce wedges in permafrost a t the same temperature . On the basis of these studies Stevens concluded that detect ion of massive ice in mater ia l of this type was not possible because of lack of velocity contrasts.

28r 40% MOISTURE BY VM RIDEAU CLAY

X 24 -

5 20- s UJ

8 1 6 -

E 12- !-

1 8 - w n

z:

4 - I

Figure 2 . Dependence of relative permittivity (dielectric constant) on temperature, based on high- frequency measurements made by Annan and Davis ( 1978).

S A N D S T O N E

S A N D S I L T

C L A Y

Figure 3. Dependence of velocity on temperaturt from observations made by Aptikaev (1964) .

?

140-

120-

100-

0.60 -

0.40-

Y \

0.20 -

+ F'

fl-

95

approaching that of ice, with the reduction continuing during f reezing unt i l water is no longer available or t h e f r e e z i n g r a t e is no longer appropriate. Coarse- grained materials undergo l i t t le density change through ice l ens format ian bu t can conta in i ce masses formed by other mechanisms such as ice wedge development . The densi ty and ice content of e a r t h mater ia ls have been examined by rad iometr ic techniques, Density has also been used as the c r i t i ca l pa rame te r in determining dis t r ibut ion of large ground ice features by gravi ty techniques.

Most geophysical techniques used in permafrost studies respond to changes in acoustic velocity, e lectr ical res is t ivi ty , re la t ive permit t ivi ty , loss tangent and densi ty or to changes in combinations of these parameters . In te rpre ta t ion of t he r e su l t s obtained f rom the geophysical measurements yields only values and distribution of values of these parameters . An addi t ional s tep is required to cor re la te the in te rpre ted parameter va lues wi th permafrost conditions.

C. Problems Amenable to Solution by Geophysical Techniques

To he lp s t ruc ture th i s paper and to provide an indication of the many geophysical systems and their unique character is t ics , two tables were prepared. The f i rs t in t roduces the techniques and associated methods. The techniques are grouped in four general c lasses: e lectr ical , e lectromagnet ic , se ismo-acoust ic and miscellaneous. Methods in the f i r s t two c l a s ses a r e r e f e r r e d to the f r equency r ange of the exc i t a t ion used in the measurement (Table I). The methods l is ted under these t echniques a re a l l t rea ted independent ly in the followingdiscussion. This is done with the aid of Table 11, which indicates how the varous geophysical techniques have been applied t o problem solving in permafrost regions. This table includes all t h e geophysical techniques and specific methods that have recent ly been ut i l ized in permafrost s tudies in North America. Character is t ics of the me thods cove red inc lude t he ene rgy o r exc i t a t ion sou rce and i t s frequency. A general discussion of t h e t y p e of equipment used includes a descr ipt ion, i t s s tage of

Ternparalure.'C

Figure 4 . Influence of temperature on unfrozen water content from Anderson and Morgenstern (1973) .

In general , then, res is t ivi ty and veloci ty increase and re la t ive permit t ivi ty and loss tangent decrease as tempera ture decreases th rough 0°C. I t is impor tan t to note tha t these t empera ture-dependent changes a re the r e su l t of the fo rma t ion of ice in the mater ia l under study, and thus need not occur exactly at 0°C. If t h e po re wa te r is sal ine, for example, ice may not form unt i l the temperature drops s ignif icant ly below zero. Thus the posit ion of a freezing f ront determined by geophysical techniques may differ con- s iderablv f rom the aosi t ion of t h e 0°C isotherm. (Kurfurst et al., 1974).

I

Table I. Geophysical Techniques and Associated Methods.

In addition to the ini t ia l change in the parameters caused by ice f o r m a t i o n , t h e progressive change in propert ies with dec reas ing t empera tu re can be r e l a t ed to the amount of unf rozen water tha t can remain in so me mater ia l s (Tice et al., 1978). The i l lustrat ion f rom Anderson and Morgenstern (1973) (Figure 4 ) helps to indica te the l a rge quant i ty of unf rozen water tha t can occur at tempera- t u r e s as low as -5.O"C in some m2,terial.

The density of e a r t h m a t e r i a l s is an addi t ional parameter to which some geophysical techniques are l inked. The density of some soils can be g rea t ly reduced when they are subjected to freezing. This degree of change can vary with soil grain size, availabil i ty of water , and f reezing his tory, t he s ame pa rame te r s t ha t i n f luence t he frost heaving character is t ics of a soil. Ice lenses forming in f ine-grained soils (silt and clay) can reduce the soil density to a value

Frequency (Hz) 10 100 I k IOk lOOk IM IOM IOOM IG I I I I I I

)C Electrical and Electromagnetic -IP+ iP Rodlo Wave

k MT -,YLF,. LF -,AM-B_ciB , I I

i- EM Sounding r Radar -I

Lob k *I

I Seismo-Acoustic

Seismic Acoustic - - _ _ Lab w

I Miscellaneous

Thermal Logging Gravity Magnetic Radiometrlc

1 96

- 2 N Y

1

j a a

97

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7H 005-5

ZH OOG-5

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100

development , and terms or t rade names commonly used for ident i f icat ion. Discussion indicates the applicability of existing equipment for ground or airborne s tudies , and more specif ical ly for land, mar ine or borehole investigations*

Permafrost problems amenable to solut ion by geophysical means fall into two major groups: defining distribution 2nd determining properties. The problem o€ defining permafrost d is t r ibut ion is subdivided into definit ion of horizontal l imits (mapping) and vertical limits (sounding). Mapping of the horizontal limits of permafros t is, for many engineering projects, most cri t ical in thc southern, more discontinuous permafrost zone (Brown, 1967), because of the f requent t rans i t ions from frozen to thawed mater ia ls . In such cases thawed mater ia l .surrounds local f rozon zones. In contrast , in the more cont inuous zone, permafrost mapping problems a re re la ted to determining the shape and the s ize of taliks.

The study of ver t ical l imits or dis t r ibut ion of permafrost involves determining i ts upper and lower boundaries, as well as the pos i t ion of thaw zones within the permafrost sect ion. The great var ia t ion in permafrost th ickness f rom several meters at i t s southern boundary to severa l hundred meters in t h e f a r north (Brown 1970) imposes a wide variety of equipment requirements. The various methods all have cha rac t e r i s t i c e f f ec t ive dep ths of penetrat ion, wi th some methods sui ted only for qual i ta t ive de te rmina t ion of one of the ver t ica l l imi t s .

In te rpre ta t ion o€ most of the da t a acqu i r ed by t h e m e t h o d s to bc discussed is based on simple models. The model for horizontal d is t r ibut ion of permafros t (Figure 5a) assumes la te ra l var ia t ion in t empera ture f rom va lues above 0°C to values below O'C, In geophysical terms this model has high relative Permittivity, high loss tangent, low resistivity, low velocity and normal density in the region with t empera tu res above O'C, and low relative permit t ivi ty , low loss tangent, high resist ivity, high velocity and sl ightly lower density in the region with temperatures below 0°C. The contac t be tween f rozen and unfrozen zones is considered to be well defined by relat ively sharp changes in the e lec t r ica l p roper t ies .

Thawed zone Permafrost

Surface

T >ooc < P C

tan d,, K~~ } Large Small

Small Large "I e

Figure 5a. Simple Model for Iforizontnl permafrost distribut,ion.

The model for ver t ical permafrost d is t r ibut ion (Figure 5b) assumes a situation in which geophysical propert ies depend only on depth and are la teral ly invariant . The s implest model assumes two homogeneous layers: a frozen layer represent ing permafrost , and an underlying unfrozen layer . In t h e unfrozen layer re la t ive permit t ivi ty and loss tangent a r e high, resist ivity and velocity are low. In t h e

101

f rozen layer re la t ive permit t ivi ty and loss t angent are The massive ice c lass is ex t remely genera l and comparit ively low and resist ivity and ve loc i ty a re high. includes a l l large ice masses found incorporated in I f the model is for summer condi t ions, i t is necessary perennially frozen, usually ice-rich materials. The ice to add an upper unfrozen layer. features include pingo ice , wedge ice , large lenses and

ice layers and bands.

T KHF~ tan ~ H F Q, V Surface laurnrnerj

Active layer > O W Large Small

Permafrost <OoC Small Lame

Thawed zone >PC Large Small

Figure 5b. Simple Model for Vertical permafrost distribution.

The most common and successful application of permafrost geophysics has been for permafrost distribution studies. Some of the ear l ies t permafros t geophysics efforts in Alaska were directed toward providing information on the horizontal extent of permafrost . Limits of permafros t were de te rmined by resist ivity methods in early studies by Joesting (1941) and Barnes and McCarthy (1964). The latter study employed shallow seismic refraction, and DC resistivity. Past work and more recent investiga- t ions supported with new equipment and procedures cont inue to demonst ra te tha t da ta can be acqui red on permafrost l imits in geological sett ings where adequate geophysical contrast exis ts between the frozen and thawed mater ia ls (Arcone et a!., 1978; Hoeks t ra et al., 1975; Seguin, 1978; Scott and Hunter, 1977; Annan and Davis 1978; Rennie et al., 1978, Rogers and Morack, 1978).

Geophysical studies in Permafrost regions have been directed more recent ly to charac te r i s ing permafros t p roper t ies . The proper t ics amenable to geophys ica l de te rmina t ion a re i ce conten t and mater ia l type. The property unique to permafrost and to which most practical problems can be re la ted is ground ice content. For this reason part of t h e applications section of Table I1 is devoted to ground ice. The ground ice types have been grouped into three c lasses for comment : porc i ce , l ens i ce , and large massive icc features. This is a simplified grouping compared to the c lass i f icat ion schemes discussed by P & w i (1 9631, These classes were se lec ted because they can have dis t inct ly different physical p roper t ics to which some of t h e m e t h o d s c a n b e sensitive.

Pore ice occurs in the na tura l vo ids in ear th materials. The volume may vary from saturation of the vo ids to fi lms of ice on void surfaces or grain contact points . Formation of pore i ce is primarily responsible for init ial changes in proper t ics of most mater ia l types .

Ice lenses are small ice masses that form when water moves to a frcczing f ront . This process forms lent icular ice (excess ice) which upon melting results in moisture contents in excess of saturat ion and void rat ios in f rozen soi ls that commonly exceed uni ty . These fea tures a re un ique to m a t e r i a l s t h a t a r e f i n e grained such as silts and clays. An arbi t rary l imit of several cent imeters in thickness was selected for the upper size of the lenses in this category, wi th a l l larger lenses placcd in the massive ice class.

Acquir ing information on ground ice cont inues to b e a s ignif icant chal lenge even though adequate geophysical contrast exis ts between ice and some mater ia l types . The best opportuni ty for success exis t s in geological sett ings where subsurface condi t ions are very homogeneous and var ia t ion in geophysical parameters can be re la ted to a single var iable such as changing ice volume. Even under these idea l condi t ions the resu l t s can be adversely influenced by such variables as ground tempera ture and ma te r i a l t ype (Arcone et al., 1979). In some mater ia l s low ground temperatures reduce the unfrozen water content of the sed iment to the point where contrast in physical propert ies of f rozen ice- rich sediment and massive ground ice is significantly reduced.

Several recent invest igat ions based on observat ions made with e lectromagnet ic and gravi ty techniques have i l lustrated that under some ground condi t ions data can be acquired on dis t r ibut ion of ground ice masses (Dclaney et al., 1977; Kovacs and Morey, 1979; Bertram et al., 1972; Arcone et al., 1978, Arcone et al., 1979; Osterkarnp and Jurick, 1979; Rampton and Walcott, 1974, Hunter et al., 1975, Scott and Hunter, 1977). In most of t h e cases c i t e d t h e invest igat ions provided information on the large ground ice masses such as wedges and lenses. Obviously the detect ion and character izat ion of permafros t a re dependent in most geological situations on the cont ras t s be tween ice- f ree g round and ground containing ice. l lnt i l recent ly few a t tempts to charac te r ize g round ice dis t r ibut ion wcre made or were even possible because of the l imited capabi l i ty of most techniques to resolve local variabil i ty in ground conditions, and small contrasts between some ground ice types and ad jacent mater ia l .

Table I1 a lso indicates which methods have been used to provide information on subsurface mater ia l types. Natural variations in the p rope r t i e s of e a r t h mater ia l s can signif icant ly inf luence the parameters to which geophysical methods respond. Aspects such as grain size of sediments , d is t inct ion between sediment and rock, and presence of metal l ic minerals can be determined. Many geophysical methods have historically been used in nonpermafrost sett ings to de termine d i f fe rences in rnaterial types and properties. For example, well established relatmnships exist for resist ivity as a function of grain s ize of mater ia l ( Jackson et al, 1978). Many of these relationships still apply even in permafrost regions where a general increase in values is associated with incorporated ice (Sellrnann et al., 1777).

11: ELECTRICAL TECHNIQUES

A. DC Resis!iyity Method

The DC resist ivity method is one of t he mos t commonly used for permafrost s tudies . I t involves passing current through the ground between electrodes and measuring the resul t ing potent ia l d is t r ibut ion through other clcctrodes. The excit ing current commonly is either DC or at an ex t remely low frequency, 15 hz or less , and the penetrat ion depth

controlled by electrode geometry. Since the method has been in use for more than 50 years techniques for interpretat ion are wel l developed, par t icular ly for layered models. Recent advances in applying inversion techniques to the i n t e rp re t a t ion of DC resis t ivi ty data (Inman, 1975; Pelton et al., 1978); Rijo et al., 1977; Zohdy, 1975) allow the determination of both la teral and ver t ical var ia t ion of resis t ivi ty together with some e s t i m a t e of the reliabil i ty of the interpretat ion. Since penet ra t ion is a function of t he s i ze of the exc i t i ng array, increased penetrat ion causes a loss in la teral resolution. If the ver t ical res is t ivi ty dis t r ibut ion contains large contrasts in res is t ivi ty , the sounding technique may no t be ab le to resolve small thicknesses of highly resist ive permafrost (Scott and Mackay, 1977). In general , however, the resist ivity technique on land has proven extremely useful for studying both horizontal and vertical distribution of permafrost and has gained wide acceptance. (Wyder et al., 1973; Scott and Hunter, 1977; Ghosh and Halloff, 1974; Cooper, 1974; Seguin, 1977 and 1978; Haeberli, 1978).

Es t ima t ing t he concen t r a t ion of ground ice in a permafrost sect ion by correlat ion with the interpreted resist ivity distribution is not always simple. In f ine grained sediments small variations of tempera ture can produce large var ia t ions in resist ivity which could be mistaken for variations in pore ice content , (Olhocft, 1975; Hoekstra et al., 1974, Seguin, 1978). However, as the concen t r a t ion of ice increases and as ice occurs more in lenses and in massive form, a combination of interpreted res is t ivi ty and geometry becomes increasingly useful. With experience in a given area, one can ident i fy the type of ma te r i a l present in a permafros t section with some reliability. (Hoekstra et al., 1975).

In r ecen t yea r s a t t empt s have been made to employ the DC resis t ivi ty method in shal low waters having low salinity for mapping the distribution of sub- bot tom permafros t (Scot t , 1975a; Scott and Hunter, 1977). While present experience is extremely l imited the concept shows considerable promise both for mapping permafrost distribution and possibly for de t e rmin ing t he ice content and mater ia l type within sub-bottom permafrost regions.

DC resis t ivi ty measurements have been made in boreholes to loca te i n t e r f aces be tween f rozen and thawed zones in complicated permafrost condi t ions. Such measurements have been used along with other geophysical data to assist iron-ore mining operations in permafrost regions. (Seguin, 1978).

Since there is in general a large contrast in res is t ivi ty between f rozen and unfrozen mater ia l of the same type , and s ince DC resis t ivi ty methods can be readi ly interpreted to yield subsurface resistivity distributions, t h e DC resistivity rnethod continues to be used to s tudy a number of permafrost problems. The major disadvantage of DC resist ivity techniques is the s low ra te at which da ta a re t aken , Each measurement requires ground contact at a minimum of four points, and as a resul t the t ime required for a large survey is great . With the development of non- c o n t a c t m e t h o d s for res i s t iv i ty measurement , the DC technique is receiving less emphasis, but it will likely continue to provide a useful approach for solving some permafrost problems.

102

0. Spontaneous Polarization Methods The Spontaneous Polarization, self potential or

SP method involves the determinat ion of the reg iona l s ta t ic po ten t ia l d i s t r ibu t ion which a r i ses because of e lec t rochemica l d i f fe rences in the subsurface. The SP method is well known in mineral prospecting and consequent ly commercial equipment is readily available (Telford et al., 1976). The SP method has, however, not been widely applied in permafrost studies.

In laboratory s tudies s ignif icant potent ia l differences have been observed across the interface between ice and water during f reezing. The observed po ten t i a l d i f f e rences a r e a function of t h e r a t e of freezing and of the ion ic conten t of t h e w a t e r (Pe te ra , 1973; Yarkin, 1973). Large potential differences have a lso been observed in the f ie ld across the i n t e r f ace be tween f rozen and t hawed po r t ions of the act ive layer (Mackay, 1978) and in dr i l l holes across frozen zones in discontinuous permafrost (Seguin, 19771,

S ince t he magn i tude of the f r eez ing po ten t i a l depends on movement of the f r eez ing f ron t i t i s un l ike ly tha t the SP technique wil l be useful in mapping the horizontal d is t r ibut ion of permafros t when that d is t r ibut ion is stable. However, in s i tua t ions where permafros t is aggrading or where an ac t ive l ayer i s f reez ing the method shows some promise of yielding an indication of t h e rate at which freezing is progressing. Since interpretation techniques for SF' me thods a r e no t weII developed even in non-permafrost applications, (Telford et al., 1976, p. 468) i t appears unl ikely that SP methods will be useful in de te rmining the p roper t ies of permafrost sect ions, except where measurements are made in boreholes.

C. Induced Polarization (IP) Methods

The Induced Polarization method is a special case of t h e DC resist ivity method in which the measurement of resist ivity is extended to include de te rmina t ion of the low-frequency re la t ive permi t t iv i ty of the ear th . Signif icant values of re la t ive permi t t iv i ty a r i se f rom the per turba t ion of e lectr ical polar izat ion on the su r f ace of par t ic les when cur ren t is applied to the ground. The IP technique is commonly used for prospecting for metallic sulphides, which exhibi t s t rong surface polar izat ion (Telford et a]., p. 702 et seq). In the absence of su lphides , the degree of polarization of frozen ground var ies wi th t empera ture and ice conten t (Olhoeft , 1975). Field measurements have proven the uti l i ty of the t echnique for permafrost s tudies but i t is still not widely used in North America, although it has been employed in the USSR (Melnikov and Snegircv, 1973).

D. Summary

Among the e lectr ical techniques DC resist ivity has ach ieved widespread acceptance for use in studies of permafrost d is t r ibut ion and analysis of proper t ies in the pe rmaf ros t s ec t ion . O the r me thods such as SP and IP may have re levance to particular problems but have not achieved widespread acceptance in permafros t work in North America.

103

111: ELECTROMAGNETIC TECHNIQUES A. Natural Field Magnetotelluric Methods

Magnetotelluric (MT) methods uti l ise naturally occuring e lectromagnet ic f ie lds within the ear th . The long period, low frequency part of these f ie lds is caused by the i n t e rac t ion of so la r s torms wi th the ear th ' s magnet ic f ie ld whi le the shor t per iod , h igh f requency par t is caused by atmospheric discharge of e lec t r ic i ty . In both cases the f ie lds in t h e e a r t h a r e horizontally-polarized plane waves propagating vertically downwards.

In t h e MT method, observation depth or penet ra t ion is a func t ion of t he f r equency of the s ignal being measured. Use of the MT method involves measur ing bo th the e lec t r ic f ie ld and the o r thogonal magnet ic f ie ld at or near the sur face , From the ra t io of these two quant i t ies an apparent res i s t iv i ty can be calculated. Measurement at many f requencies provides information on the var ia t ion of resist ivity with depth. Inversion techniques for interpretation of MT d a t a a r e n e a r l y as well developed as for DC resist ivity (Nabetani and Rankin, 1969; Rankin et al., 1974). Some success has been achieved with short period MT (audiofrequency MT or AMT) in measuring both the thickness and the horizontal d is t r ibut ion of permafrost (Kotiar and Strangway, 1975 and 1978; Rossiter et al., 1978). The interpretation of t h e presence of ground ice or of m a t e r i a l t y p e a p p e a r s t o be beyond the l imits of accuracy of the technique. The MT method has an advantage over DC resist ivity in determining the thickness of very thick permafrost sect ions s ince the exict ing f ie ld occurs natural ly and consequently does not require elaborate high-powered generators for i ts u t i l izat ion, Natural f ie ld MT has not , however , ach ieved grea t acceptance in the s tudy of permafrost conditions.

8. Artificial Field Magnetotelluric (Radiowave) Methods

Artificial f ield MT or rad iowave methods a re similar to natural f ield MT methods with the except ion tha t the e lec t r ica l and magnet ic f ie lds be ing used a re genera ted by t r ansmi t t e r s at d is tances of severa l wave lengths o r more for the s tudy a rea (Col le t t and Becker, 1967). Measurements are made in the VLF (3-30 kHz), LF (200-400 kHz) and AM broadcast (500-1500 kHz) frequency ranges. Observation depth or penet ra t ion is a funct ion of frequency (Figure 6) and is general ly l imited by t h e high frequency of t h e signals utilized, although this limitation is less significant in high-resistivity permafrost. Commercial ly avai lable equipment can be ut i l ized to measure sur face impedence at VLF and LF and thus to de te rmine res i s t iv i ty in the same manner as for natural f ie ld magnetotel lur ic methods. Radiowave methods have not been used in a marine environment because of the shielding effect of conductive seawater . Commercial ly avai lable equipment can be used to obtain resist ivity by measurement of wave t i l t .

Radiowave techniques have been used with considerable success to m a p l a t e r a l var ia t ions in surface impedance and consequently to determine horizontal d is t r ibut ion of permafrost (Hoekstra and McNeill, 1973; Hoeks t ra et al., 1977; Scott and Hunter, 1977; Arcone et al., 1978, Sellmann et al., 1977). Making measurements at severa l f requencies in the ava i lab le r ange pe rmi t s t he de t e rmina t ion of ver t ical var ia t ion

of resist ivity and consequently of permafros t distribution. Measurements at VLF c a n b e m a d e vir tual ly anywhere in North America, but measurements a t LF and in the b roadcas t band a re l imited by the short range of usefu l t ransmi t te rs in permafrost regions in northern North America (Sellmann et al., 1974 and 1977, Arcone et al., 1979).

In te rpre ta t ion t echniques for the rad iowave methods are re la t ively undeveloped, a l though curves for in te rpre ta t ion based on a two-layer model are available (Gconics, 1971) as are su i tes of model resul ts (Madden and Vozoff, 1971). Advances have been made in the i n t e rp re t a t ion of VLF wave-impedance measurements in thin permafrost by considering both t h e m a g n i t u d e of t he wave impedance and t he phase d i f f e r e n c e b e t w e e n t h e e l e c t r i c a n d m a g n e t i c components of the f ie ld (Powell , 1978).

With experience in a given region, some e s t i m a t e s of the i ce con ten t of a permafrost sect ion can be made on t he bas i s of apparent res is t ivi t ies , de te rmined f rom sur face impedance measurements (Scott and Hunter, 1977; Arcone et al., 1979). With experience in a given region i t is also possible to make s o m e e s t i m a t e of ma te r i a l t ype if t h e r e is good correlat ions between geological var ia t ion and resistivity (Scott, 1975b).

Radiowave techniques or measurement of surface impedance have achieved considerable acceptance in North America because they are s impler to use than DC res i s t iv i ty and because the resu l t s a re useful in studying permafrost . Surface impedance measurements s t i l l require contacts to b e m a d e w i t h the ear th . Consequent ly , a l though they a re fas te r to make than conventional DC resis t ivi ty , they are not so f a s t as the non-contact e lectromagnet ic methods.

Non-contact radiowave measurements (wave t i l t ) have been made on an experimental basis on McNeil l and Hoeks t ra (1973). This approach has been applied in a rout ine manner on ly f rom the a i r . S ince in a n airborne survey i t i s d i f f icul t to achieve de ta i led la teral resolut ion (Arcone 1977 and 1979) , the a i rborne

I o3 k , t -.

4

Frequency. Hz

Figure 6. 7he skin depth of electromagnetic radiation as a function of frequency at several values of ground resistivity.

wave t i l t o r E -phase* t echn ique i s mos t u se fu l to o b t a i n a genera l ized p ic ture o f res i s t iv i ty d i s t rubut ion and consequen t ly of pe rmaf ros t d i s t r ibu t ion . The a i r b o r n e w a v e t i l t t e c h n i q u e i s m o r e u s e f u l i n a r e a s w h e r e p e r m a f r o s t is t h i c k e r t h a n 100 m e t r c s ( S c o t t and Hun te r , 1978).

C. Induct ive-Elec t romagnet ic Methods

Induc t ive E lec t romagne t i c (EM) me thods u se a loc:ll e l e c t r o m a g n e t i c t r a n s m i t t e r to g e n e r a t e a f ie ld wh ich i nduces eddy cu r ren t s in t h e e a r t h . T h e s e e d d y c u r r e n t s p r o d u c e a secondary f i e ld wh ich i s de t ec t ed b y a n e l e c t r o m a g n e t i c r e c e i v e r . T h e e d d y c u r r e n t magn i tude i s r e l a t ed to the conduc t iv i ty of t h e e a r t h . EM sound ing t echn iques can i nc rease pene t r a t ion e i the r by i nc reas ing t he s epa ra t ion of t h e t r a n s m i t t e r a n d r e c i e v e r o r m o r e c o m m o n l y b y d e c r e a s i n g t h e f r e q u e n c y of e x c i t a t i o n a n d k e e p i n g t h e s p a c i n g of t r ansmi t t e r and r ec i eve r f i xed . Equ ipmen t is commercially ava i lab le to per form soundings by e i ther approach .

E x p e r i e n c e in Alaska and i n no r the rn Canada has shown tha t va r i ab le f r equency sound ing can g ive r easonab le c s t ima tcs of pe rmaf ros t t h i ckness in a r e a s w h e r e t h e t h i c k n e s s is of t h e o r d e r s of t h e 100 m e t r e s o r l a rge r (Dan ie l s et ai., 1976; Ghosh & Hallof , 1974). R igorous i n t e rp re t a t ion t echn iques fo r c l ec t ro - m a g n e t i c s o u n d i n g a r e at t h e p r e s e n t t i m e l i m i t e d to s imple l aye red s i t ua t ions i n wh ich t he number of layers i s smal l . The use of v a r i a b l e f r e q u e n c y e l ec t romagne t i c sound ings to s tudy complex pe rma- f r o s t s e c t i o n s is s t i l l v e r y d i f f i c u l t . S i n c e t h e t e c h n i q u e c a n g i v e e s t i m a t e s of t h e r e s i s t i v i t y of v a r i o u s l a y e r s t h e s e e s t i m a t e s c a n b e c o r r e l a t e d w i t h ice c o n t e n t in a known soil t y p e ,

Smal l po r t ab le EM uni t s have been bu i l t wi th f i x e d s p a c i n g s b e t w e e n t r a n s m i t t e r a n d r e c i e v e r c o i l s (McNeil l , IY76; Delaney et nl,, 1977; Henderson and Hoekstra, 1977; Rennie and Henderson, 1979). The o p e r a t i n g f r e q ~ n c i e s of t h e s e i n s t r u m e n t s a r e c h o s e n low enough t ha t , f o r a l l r e s i s t i v i t i e s w i th in t hc r ange of ( :ahbra t ion , pene t ra t ion is l imi ted by t h e t r ansmi t t e r - r ec i eve r spac ing r a the r t han by sk in dep th e f f e c t s . T h e s e i n s t r u m e n t s h a v e b e e n u s e d w i t h cons iderable success to d e t e r m i n e n e a r - s u r f a c e l a t e r a l d i s t r i b r ~ t i o n of e lec t r i ca l r e s i s t i v i ty and consequen t ly to map t he ho r i zon ta l d i s t r ibu t ion of p e r m a i r o s t . Within a known soil type in a known geologica l se t t ing t h e r e s u l t s of such su rveys can also be used to i n f e r i c e con ten t and mass ive ice dis t r ibu t ion and , to a l i m i t e d e x t e n t , to e s t i m a t e , t h e t h i c k n e s s i n a r e a s w h e r e i t is c o m p a r a b l e to t h e p e n e t r a t i o n of t h e s y s t e m (Hoeks t ra , 1978) . Measr~rernents at n number of t r ansmi t t e r - r ec i eve r spac ings can g ive a g o o d e s t i m a t e of t h e v e r t i c a l d i s t r i b u t i o n of p e r m a f r o s t (Scl lmann et al., 1979). As a resu l t of t h e s u c c e s s expe r i enced w i th t h i s me thod i n s tud ie s i n A laska and n o r t h e r n C a n a d a , t h c t n e t h o d h a s a c h i e v e d clonsiderable acc:eptat\c:e in N o r t h A m c r i c a f o r mapping thc dis t r ibu t ion of shzllnw p e r m a i r o s t in t h e d i s c o n t i n u o t ~ s 7.orw.

An e l e c t r o m a g n e t i c i n d u c t i o n s y s t e m c a r r i e d by a he l icoptcr has been used to m a p per rnaf ros t d i s t r ibu t ion in the d i scont inuous 7one in the Mackenzie Vallcy, N.W.T. ( f rascr , 1'378). ' k t echn ique p rovcd use fu l fo r i dcn t i fy ing l a rge pe rma l ros t f ea tu re s and

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fo r de t e r rn in ing ma te r i a l t ypes on a l a rge s ca l e . The reso lu t ion l imi t s inherent in an a i rborne sys tem p r e v e n t e d m a p p i n g p e r m a f r o s t d i s t r i b u t i o n i n t h e s a m e d e t a i l t h a t can be ach ieved by g round measu remen t s . Such sys t ems a r e , however , f r equen t ly u sed to prospec t for meta l l ic su lphides in permafros t reg ions .

Induc t ion t echn iques a r e comtnon ly u sed to log we l l s d r i l l ed fo r pe t ro l eum exp lo ra t ion o r p roduc t ion i n permafros t reg ions (Hnat iuk and Randal l , 1977) . The e s t i m a t e d r e s i s t i v i t i e s a r e u s e d i n c o m b i n a t i o n w i t h o t h e r g e o p h y s i c a l p a r a m e t e r s t o d e t e r m i n e t h e posi t ion of t h e b a s e of p e r m a f r o s t i n t e r s e c t e d i n t h e pa r t i cu la r ho le . In t e rp re t a t ion t echn iques fo r i nduc t ion l ogg ing a r e we l l deve loped , and consequen t ly t h e r e s i s t i v i t i e s so d e t e r m i n e d c a n b e u s e d w i t h s o m e conf idence .

In t h e l a s t f i v e y e a r s e l e c t r o m a g n e t i c s o u n d i n g and p ro f i l i ng me thods have ga ined cons ide rab le popular i ty in Nor th Amer ica in mapping per tnaf ros t d i s t r ibu t ion because t hey a r e s e l f - con ta ined and do no t r e l y as s i g n a l s f r o m d i s t a n t t r a n s m i t t e r s . A growing a c c e p t a n c e o f e l e c t r o m a g n e t i c t e c h n i q u e s is probably the mos t s ign i f i can t deve lopmen t in p e r m a f r o s t geophys ic s i n Nor th Amer ica s ince t he l a s t pe rmaf ros t conference in Yakutsk .

n. Radar Me thods - ~ - R a d a r m e t h o d s u s e l o c a l a n t e n n a s to r a d i a t e

s igna ls and to r ece ive echos o r r c tu rns f ro rn r e f l ec t ing in t e r f aces . The f r equency r ange fo r g round-p rob ing r ada r t echn iques i s f rom 1 M e g a h e r t z to 1000 Megaher t z . Pene t r a t ion is l imited pr imari ly by a t t e n u a t i o n of t h e r a d a r s i g n a l b y t h e m a t e r i a l pene t ra ted . At tenuat ion i s h ighes t in low-res i s t iv i ty ma te r i a l s , and pa r t i cu la r ly in f ine -g ra ined s ed imen t s s u c h as c l ays and s i l t s . Even when f rozen , c l ays and s i l t s t end to h a v e h i g h a t t e n u a t i o n ( D a v i s e t al., 1976).

Ground-p rob ing r ada r sys t ems u t i l i s e w ideband an tennas and impu l sc s igna l s . Somet imes na r row band an tennas r ad ia t ing pu l sed , s ing le f r equency s igna l s a r e used (Annan and navis , 19772) .

Commerc ia l ly ava i l ab le i rnpu l se r ada r s have been used on l and wi th cons iderable success ( S c o t t et ai., 1974; Annan and Davis, 1978; Kovacs and Morey, 197Y). They can be u sed in coarse-gra ined sed i rnents at depths up to 70 r n e t e r s to s t u d y p e r m a f r o s t d i s t r i b u t i o n a n d s t r u c t u r e w i t h i n t h e p e r m a f r o s t s e c t i o n . I h t e r b e r g e r (1978) h a s d e s c r i b e d a non-c:ommcrcinl system for which considerably g r e a t e r p e n e t r a t i o n is c l a i m e d . D e t e r m i n i n g t h e p r e s e n c e of g round i ce in a p e r m a f r o s t s e c t i o n b y measu r ing h igh f r equency e l ec t r i ca l p rope r t i e s a lone is d i f f i cu l t . The rc is only a s l i g h t d i f f e r e n c e b e t w e e n t h e r e l a t ive pc r rn i t t i v i t i c s of pure ice and wel l - f roz.en c l e a n s a n d w i t h s o m e e x c e s s i c e . H o w e v e r t h e h i g h r ece ive r s ens i t i v i ty , and spa t i a l r e so lu t ion of r a d a r t e c h n i q u e s p c r m i t t h e d e t e r m i n a t i o n of the georne t ry of lens and m a s s i v c ice wi th in a pe rmaf ros t s ec t ion a n d c o n s e q u e n r l y f a c i l i t a t e t h e d e t e c t i o n of i c e if s r~ i lab le cont ro l . i s ava i lab le . Radar t echniques can bc used to i n d i c a t e c h a n g e s of t n a t e r i a l type in p e r m a f r o s t s e c t i o n s a n d w i t h a d e q u a t e c o n t r o l c a n b e used t o i den t i fy rna t c r i a l t ypes , a l t hough pene t r a t ion i s g rea t ly r e s t r i c t ed i n f i ne -g ra ined ma te r i a l s (Annan and Davis, 1976).

" "E-Phase" is a p a t e n t e d n a m e of Rnrr inger Rcsearch Ltd , Rexdale , Canada .

Commercially available impulse radar equipment has been used to map the thickness of both fresh-water ice and sea ice, and to s tudy the e lectr ical propert ies of sea ice (Bertram et al., 1972; Campbell and Orange, 1974a and 1974b; Kovacs and Morey, 1978; Kovacs, 1978a and b). In the f resh-water environment radar has mapped bottom topography at water depths of up to several tens of meters f rom the i ce sur face (Annan and Davis, 1978). An impulse radar has also been used in an airborne configuration to measure i ce thickness and lake-bottom configuration (Kovacs, 197Xb).

Pulsed radar systems are commercially available in the fo rm of alt imeters and radioecho sounders. Such equipment has been used with success on the ground surface and from the air to measure i ce thickness in glacial studies and to outline glacial bottom topography (Gudmansen, 1970, Cambridge, 1975). Continuous-wave radar techniques are useful for determining the propert ies of ice within a glacier (Kovacs and Gow, 1977a and b). Pulsed radar has been used in boreholes to ident i fy the base of permafrost in solid rock (Lytle et al., 1976).

Radar techniques have for some t ime been used with success in glacier studies and are generally accepted for that purpose. Recent developments in the use of impulse radar in shallow studies of permafrost have demonstrated the potent ia l of such techniques in detailed studies for engineering purposes in a reas of coarse-grained materials. Use of ground- probing radar for permafrost studies is another significant development since the permafrost conference in Yakutsk,

E. Time-domain Reflectometry

Time-domain reflectometry (TDR) techniques (Davis and Chudobiak, 1975) have been used to study sea ice (Dogorodskii and Tripol'nikov, 1973) and near-surface act ive layer character is t ics (Pilon et al., 1979). The method involves emplacing two parallel probes in the ice or ground several centimeters apart . The probes form a transmission line along which i t is possible to t ransmit an electromagnetic signal. Discontinuities in t h e mater ia l penetrated by the probes generate ref lect ions which can be identified at the ground surface. Commercially available TI)R equipment can be used for this purpose. The technique is primarily limited by the pract ical ly a t ta inable length of transmission line. Present experience indicates a maximum penetration of the order of 2 meters.

The TDR method is useful in very detailed studics of variations in e lectr ical propert ies of t h e upper two meters, associated, for example, with the position of the f reezing f ront and ice formation in the active layer (Pilon et a]., 1979). I t is, however, less suitable for large-scale engineerillg studies, bec:ause of the required probe installation and limited depth of penetration.

F. Radio-frequency Interfeom=

The radio-frequency interferometry mcthod (RFI) has been described by Rossiter et al., (1978). This method uses a horizontal electric or magnetic: dipole as a transmitter, emitt ing signals at six f requencies f rom 1 MHz to 32 MHZ. Direct and subsurface reflected waves interface at thc ground

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surface. The interference pattern observed with increasing distance from the transmitter can be interpreted in terms of a layered model. This method is largely experimental , and is not commonly used in permafrost studies in North America,

G. Summary

Electromagnetic techniques commonly used in permafrost s tudies in North America use low and high frequency radiowaves, magnetic induction and ground- probing radar. The most significant development since 1973 is the increased use of inductive resist ivity methods, which have largely replaced DC resistivity methods for permafrost studies particularly in t h e discontinuous zone. Ground-probing radar has also ga ined acceptance in this period particularly for uses in coarse-grained soils and on sea- and fresh-water ice.

IV: SEISMIC TECHNIQUES

A. The Seismic Refraction Method

The seismic refraction method involves measuring the velocit ies of refracted compressional waves travelling through media which, for most applications, are considered to be layered. In most field situations, successful applications require that compressional wave velocities increase with depth; often, however, when this condition is satisfied, "hidden layers" or thin zones where large vclocity- depth gradients occur can be a problem (Telford et al., 1976, p. 417). In general , refract ion field methods require long source-detector offsets; hence hydrophones and geophones used must display good low frequency responses. Since refracted events are general ly of lower amplitude than reflccted cnergy, high-energy sources ate necessary and explosives continue t o be commonly used. Weight drops and marine air guns and sparker units have been successful in sorne cases.

Refraction methods were devcloped early in t h e history of geophysics and a largc number of interpretation techniques have bccn developed to interprct velocity-depth structure (Musgrave, 1967). Since refraction methods can measure velocity accurately, in permafrost they can provide estimatcs of ice- content , ground temperature and mater ia l tync and strength. Several laboratory measurements have been made in r ecen t years on rocks and soils involving comparison of shear and cornpression wave velocities a t ac:oustic frequencies with variables such as temperature, tnoisture content, pore-water salinity and sample comaosition (Dzhurik and Leshchikov, 1973; Frolov and Zykov, 1971; King and Ramford, 1971; King, 1977; Kohncn, 1974; Kurfurst and Hunter, 1976b; Nakano et al., 1971; Nakano ct al., 1972; Nakano and Froula, 1973; Nalcano and Arnold, 1973; Ogilvy, 1970; Stoll, 1974; Zykov and Baulin, 1973). From thesc studies sorne general conclusions can be drawn:

1) Cornpressional velocities inrrease with decreasing permafrost temperatures for water sa tura ted samples ; the cffect is most pronounced in soils and is a funct ion of the water content .

2) For moistutc-saturated low-salinity soils, most of the pore water is frozen at tempera tures c losc to 0°C in coarse-grained samples; as grain size decreases, the velocity increases at a m w h lower rate with decreasinR temperature.

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Hence in the f ie ld s i tuat ion, if additional information is available on the composition of subsurface soils or rock, a temperature-moisture content-sal ini ty range can be es tabl ished f rom veloci ty measurements .

The refraction method has been used to measure active-layer thickness in soils and rock glaciers (Garg and Stacey, 1973; Green, 1970; Hunter and Good,,1971; Kurfurst et al., 1974; Carson et al., 1975; Gagne and Hunter, 1975; Barsch, 1978). Good velocity contrasts exis t between the act ive layer and ice-bonded permafrost . The method is particularly applicable to problems of act ive layer thickness var ia t ions in a r e a s of thermal d i s turbance such as on road, railway or pipel ine construct ion s i tes as well as in river-bank and lake-shore studies (Carson et al., 1975; Good and Hunter, 1974; Hunter et al., 1976; Kurfurst et al., 1974; Kurfurst and Hunter, 1976a).

Seismic velocity measurements have been rnade to determine ice-bonded permafrost d is t r ibut ion and soil type a long construct ion routes (Kurfurs t and Hunter, 1976a). The most successful applications involve combined seismic and electrical surveys (Scott and Hunter , 1977). Measurement of compressional and shear wave veloci t ies and ampli tude a t tenuat ion ra tes has led to the descr ipt ion of these pa rame te r s in t h e fo rm of the "generalized acoustic parameter" which var ies as the ice content , soil type and tempera ture of the mater ia l (Akimov, 1973) . In mining applications, seisrnic compressional and shear wave velocity measurements have been used to determine the depth of overburden for s t r ipping es t imates , the quant i ty of f rozen ore and the re la t ive s t rength and b las t ing charac te r i s t ics of ice-bonded ore zones (Gary and Stacey, 1973; Garg, 1977; Carg, 1976).

Ice bodies at depth in permafrost soils have been examined by the se i smic re f rac t ion method and successful a t tempts to measure the dis t r ibut ion of ice- bonded perrnafrost and large ice masses have been made (Hunter, 1973a; Scott and Hunter, 1976; Voronkov, 1977).

Marine refract ion methods have been employed t o m a p t h e d e p t h to ice-bonded permafrost beneath t h e sea floor and to obtain estimates of t he deg ree of ice-bonding (Carson et al., 1975; Hobson et al., 1976; Hunter, 1973b; Hunter and Hobson, 1974; Hunter et al., 1974; Hunter et al., 197Xa and b; Rogers, 1976). The most definitive results have been obtained with hydrophone arrays designed specificially for shallow water refraction surveys, but refraction events p icked f rom the ear ly por t ions of records obta ined f rom re f lec t ion a r rays used for hydrocarbon exploration ran yield useful information (Hobson et al., 1976; Hunter et al., 1975; Hunter et al., IY76; Hunter and Judge, 1975). Most re f rac t ion measurements made to d a t a a r e of t h e "single-ended" type, in which the source i s at one end of the array only; hence only approximate es t imates of velocity and depth are possible unless overlapping record coverage is made (Telford et al., 1976). Reversed or "double ended" refraction profiling is possible through the use of telemetering sonobuoys. A sea-bot tom hydrophone array with reversed prof i l ing has been employed in the ice-covered ocean using avai lable leads or cracks through which to deploy t h e array (McLaren et al., 1Y75).

B. Seismic Reflection Methods

Seismic ref lect ion methods have been ut i l ized throughout the world as one of the pr imary geophysical exploration techniques for hydrocarbons. The techniques involve digi ta l magnet ic recording of seismic waves f rom a source (explosives, air gun, weight drop, or vibra tor ) re f lec ted f rom layered s t r u c t u r e at depth. Computer-assisted velocity analysis methods are now avai lable for processing multichannel reflection data. With these techniques, velocity-depth functions can be established in permafrost areas , and permafrost th icknesses and veloci t ies can of ten be obtained. Correct ions for permafros t th ickness var ia t ions a re impor tan t for most sedimentary hydrocarbon t rap mapping; cost ly dry holes can resul t f rom incorrect assumption about permafrost conditions.

In thick permafrost areas where f ine-grained mater ia l s p redominate , the base of permafros t is o f t en grada t iona l in temperature and consequent ly in veloci ty , and therefore is not a re f lec tor of seismic energy (Hunter, 1972). If r e f l ec to r s a r e no t p re sen t within the permafrost sect ion, i t s th ickness and average veloci ty can only be determined by indirect methods u t i l i z ing marker hor izons benea th the base (Agofonov et al., 1973; Card, 1977; Muzychensko and Kozyrev, 1970) . Computer model l ing techniques are available to obtain best-f i t t ing veloci ty-depth curves by this method (Card and McCallum, 1979).

The cha rac t e r of seismic ref lect ion records is of ten an indicator of t h e p r e s e n c e of ice-bonded permafrost (Hunter et al., 1976; Kanereikin et al., 1971). In marine reflection profil ing in areas where submarine permafrost i s suspected, poor record quality (large amplitude reverberations) is of ten assoc ia ted wi th thc p resence of a large velocity cont ras t a t t h e t o p of ice bonding beneath the sea- floor.

C. Acoust ic Reflect ion Methods

Acoust ic ref lect ion methods appl ied to permafros t p roblems a re main ly conf ined to the marine mode; however, experiments with high f requency (7 kHz) t ransmi t te rs and rece ivers have been a t tempted (Nelson et al., 1970). The sources commonly used in the marine mode are a i r guns, boomers ( large plates which are displaced electromagnet ical ly while submerged to gene ra t e a seismic signal) , sparkers (which discharge electrical energy across a spark gap to gene ra t e a seismic signal), and high frequency electrodynamic t ransducers . These sources a l low var ia t ion of t h e frequency and energy content of the s ignal . The source and rece ivers a re c lose ly spaced inorder to obtain nearly verticalincidence reflection recordings. High frequency content and consequent short- wavelength energy allow good resolution of small fea tures . Ref lec t ions a re ob ta ined f rom layer ing wi th la rge ve loc i ty cont ras t s at dep th benea th t he sea bottom. Since no velocity information can be obta ined , in te rpre t ing the top of ice-bonded permafrost can be subject ive in some areas , as well as qual i ta t ive, of ten requir ing control in t h e f o r m of drill holes or refraction velocit ies. If such control is ava i lab le , the acous t ic re f lec t ion technique can map de ta i led topography on the top of ice-bonded pe rmaf ros t ; t he s e i smic r e f r ac t ion me thod can no t .

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Pingo-like structures have been successfully mapped on t he sea bot tom (Shearer et al., 1971). High resolution (7 kHz) methods have also been used to de l inea te the var ia t ion in the upper boundary of permafrost in r iver channels and a long potent ia l offshore pipeline corridors (O'Connor, 1979).

To ob ta in maximum e f f ic iency in mapping thc upper boundary of ice-bonded permafros t , the acous t ic reflection technique should be applied in conjunction with the marine seismic refract ion method; both velocity variations ( ice content changes) and detailed topography of this boundary can thus be obtained.

D. Borehole Seismic Methods

Borehole seismic methods involve the measurement of f i rs t arr ival compressional wave t rave l t imes be tween a surface source and a hydrophone (or wall-lock geophone) array at depth in cased or uncased holes.

For measurement of thickenss and velocity distribution of permafros t in oil and gas exploration holes, a 12-channel array of hydrophones is used (commonly called a "crystal cable array"). Spacing between individual hydrophones is usually 15 m and t he a r ray i s repos i t ioned in the ho le a f te r each sur face shot. Usually a small quant i ty of explosives is used, but air guns have also been successfully tr ied. The resul tant t ravel- t ime-depth curve f rom the recorded f i rs t arr ivals is in te rpre ted to ex t rac t ve loc i ty information.

A "crystal cable" survey is commonly run as one of a ser ies of s tandard borehole logs in wells drilled in permafrost areas . Veloci ty measurements of ten show the g rada t iona l na ture of the lower boundary of permafros t as well as indicat ing the presence of low veloci ty zones within the Permafrost sect ion (Baird, 1976; Card, 1977; Hnatiuk and Randall, 1977; Hunter et al., 1976). Velocity correlations have been made with changes in lithology, porosity, water content and temperature (Walker and Stuart , 1976). In some cases su r face sho t s a r e d i sp l aced f rom the borehole to obta in l a te ra l ve loc i ty changes in the vicinity of the hole (Baird, 1976; Card, 1977).

An a r r ay of shots or geophones on the sur face wi th an a r ray of hydrophones or shots at dep th can yield wave-front diagrams which may be interpreted to obta in l a te ra l var ia t ions of seismic velocit ies (Gallperin, 1971; Meissner, 1961). This method has been utilized to obtain var ia t ions in permafrost s t ruc tu re in mining (Hunter, 19741, and in mapping ground ice occurrence (Scot t and Hunter , 1977) in shallow boreholes.

E. Borehole Acoustic Methods

Sonic logging tools rneasurr. the transit t ime of the f i r s t a r r iva l compress iona l wave over a known distance, usually about 30 cm, in a borehole. Unfrozen, unconsol idated mater ia l near the surface has t rave l t imes in the o rder of 500-700 microseconds/meter , whereas s imilar f rozen mater ia ls are in t h e r a n g e of 250-350 microseconds/meter (Hnatiuk and Randall , 1977). Since the range of t he acous t i c wave is small , thermal degradat ion of the pe rmaf ros t result ing in oversized holes can often lead to erroneous results. This method should be used in conjunction with other borehole tools (i.e. dual-induction lateral- log and the crystal cable).

Most sonic tools have been manufactured for use in large diameter holes dr i l led for hydrocarbon exploration. There are sonic tools under development which a re des igned for 3-10 c m holes wi th d i rec t t ransducer coupl ing to the wall rock. Such tools will no doubt be useful for future appl icat ions in shallow drill holes (King et al., 1978; Tiutiunnik and Konovalikhin, 1973; Zykov and Raulin, 1973).

F. Other Seismic Methods

Surface waves, known in the seismic industry as "ground roll", display low velocity, low frequency and high amplitude, and have been considered as noise in most refract ion and ref lect ion surveying. Attempts have been made to rninimize such interference in designing arrays and in subsequent data processing. However, with proper equipment and array design, such waves could be used to measure the thickness of near-surface layer ing (i.e. the ac t ive l ayer ) and to ob ta in e s t ima tes of shear wave velocit ies in permafros t . By accurately measuring both compressional and shear wave velocit ies of permafros t

p roper t ies o r t h e m a t e r i a l c a n b e made. mater ia l s in situ, es t ima tes of dynamic e las t ic

Other types of waves of ten considered to b e seismic "noise" result from trapping of seismic energy in a high speed layer (Hobson et al., 1976). Analyses of the modes of propagation of this energy, and its ampli tude decay, can yield es t imates of permafros t thicknesses for areas where ice-bonded permafrost th icknesses a re in the o rder of 100 m or less, and where e s t ima tes of the shear and compressional wave velocit ies of the surrounding non-ice-bonded material can be made .

The ampli tude a t tenuat ion of f i r s t a r r iva l r e f r ac t ions can be measu red to ob ta in e s t ima tes of thickness of an ice-bonded permafrost layer (Donato, 1965; Rosenbaum, 1965) for a simple model of a thin high-velocity layer embedded in a low-velocity medium. The maximum thickness measurable with the technique is f requency dependent , and for most convent ional seismic arrays the upper l imit of thickness resolution is less than 100 m,

V: MISCELLANEOUS TECHNIQUES

This section covers several geophysical methods tha t do no t f a l l i n to t he f i r s t two ma in ca t egor i e s previously covered (Table 1).

A. Magnet ic method

A very l imited amount of permafrost geophysics has been done employing the magnet ic technique. Volodko et al., 1973, descr ibe an invest igat ion which rel ied upon the magnet ic contrast between ice and f rozen minera l mater ia l for de te rmining the distribution of ice wedges based on ground measurement . The method is appl icable only when there i s an un i form d is t r ibu t ion of magnet ic mater ia l in the soi l surrounding the wedges, so t ha t t he wedges show as weak negative anomalies.

A field survey was conducted in an area of al luvial soi ls that had magnet ic suscept ibi l i ty values that apparent ly ranged f rom 20 X t o 200 X CGSu, depending on ground ice volume and local mineralogy. Dril l ing of 29 holes in the study area conf i rmed t ha t a correlat ion exis ted between negat ive

anomalies and ice wedges. Some exceptions to this appear to be co r re l a t ed w i th a r eas of h igh ice conten t in the adjacent mineral mater ia l .

I t is unlikely that the magnetic method will ever become widely used for permafrost s tudies .

8. Gravity met_=

Only limited use has been made of gravity methods in permairost s tudies , even though they have been applied to ice thickness measurements in glaciological studies (Barnet et al., 1956; Bentley, 1961t).

From glacier s tudies Ostenso et al., (1965) it has been determined a I-mgal anomaly is equal to be tween 13.5 meters and 20 me te r s of ice, depending on the relationship used. The 13.5 me te r s was de t e rmined f rom f la t p la te theory whi le the 20 me te r s was determined f rom empir ical re la t ionships f rom glaciers with irregular bottom topography. If field measurements can be made to an accuracy of 5 0.1 to 0.2 mgal and o ther fac tors a re idea l th i s sugges ts tha t var ia t ions in excess ice in the order of a f ew me te r s in thickness could be detected.

Gravity studies have been conduc:ted for the purpose of s tudying permafrost in northern Canada by Rampton and Walcott (1974), who investigated three s i tes for which some ground control was available. Excess ice thickness was determined by ca lcu la t ing Bouger densit ies for the topography af ter removing l inear t rends in the data . The amount of ice required to produce these densit ies was proportioned, and var ia t ions f rom the average thickness of i ce i n t he topography were calculated by applying the inf ini te s lab io rmula to the residual anomalies. The technique worked wel l in the area s tudied and provided close agreement with control data .

Osterkamp and Jur ick (1979) examined a s i t e near Fairbanks, Alaska, to correlate gravity observations of ground ice dis t r ibut ion with control avai lable f rom both dr i l l holes and exposures formed during highway construction. Preliminary interpretat ion indicated a correlat ion between gravi ty anomal ies and a reas of massive ice.

The gravi ty method does not provide the exact dep th of an ice mass , I t does, however, provide an e s t i m a t e of the amount of excess ice, when some cont ro l is ava i lab le and when the s tudy a rea has uni iorm geology, with ice volume being the major var iable . Kampton and Walcot t noted that l inear trends in thickness of excess ice were diff icul t to detect . Uniform ice s labs under the ent i re s tudy area were also difficult to de tec t un less a sec t ion of t h e prof i le crossed an ice-free zone. In the i r s tudy t he technique helped to establ ish some re la t ionships between surface relief and ground ice distribution.

C. Radiometr ic techniques

The most commonly employed radiometric techniques for shallow engineering borehole studies in pe rmaf ros t a r e ac t ive gamma (gamma-gamma) and neutron (gamma-neutron) methods.

The gamma-gamma logging methods are more versa t i le than the o r ig ina l na tura l gamma method, which only measures natural radiat ion. Natural gamma methods were used in i t ia l ly by the o i l indus t ry for dist inguishing between various l i thologic units with

108

di f fe ren t concent ra t ions of rad ioac t ive e lements . An advantage of the gamma technique i s tha t it can be used in cased drill holes.

The gamma-gamma logging method uses a borehole package that contains a gamma-ray source as well as the counter , The source and the scint i l lometer a re pos i t ioned at a cons tan t spac ing and a re he ld against the hole wal l . A col l imated beam of gamma rad ia t ion is d i r e c t e d i n t o t h e e a r t h m a t e r i a l w h e r e scat ter ing and absorpt ion take place on the path to t h e sensor. The intensity of the de tec ted gamma rays is a func t ion of rock density (Telford et al., 1976). The la rge d i f fe rences in bulk density and electron density be tween ice and mos t soil and rock make this technique wel l sui ted for ground ice detect ion and densi ty determinat ions. Obtaining quant i ta t ive values for these parameters would require local cal ibrat ion in ma te r i a l of known properties (McKay and O'Connell, 1975; Scot t and Hunter , 1977).

The neut ron method can u t i l i ze a gamma-ray source and a neutron detector . The neutron intensi ty de t ec t ed i s r e l a t ed t o t he amoun t of hydrogen in t h e ear th mater ia l and, therefore , can be used to de termine water conten t ( f rozen or unf rozen) . Used in a dry hole, the tool can give additional information on t h e p r e s e n c e of high ice-content zones.

A logging system employing both gamma-gamma and neutron probes was developed for use during cons t ruc t ion of the Alyeska Pipel ine in Alaska. The equipment was designed for rapid logging in low- densi ty mater ia l such as ice-rich permafrost . Both denis ty and moisture-content data were rout inely obta ined with t he sys t em in holes dri l led for placement of ver t ical support members for the pipe (Metz, 1976).

Investigations using gamma-gamma and neutron logging to provide information on density and ground- ice content have been descr ibed by Scot t and Hunter (1977) and McKay and O'Connell (1978).

n. Tempera ture measurements

Tempera tu re measu remen t s r ep resen t t he mos t fundamenta l geophys ica l approach to ob ta in ing information on permafrost d is t r ibut ion and zones where propert ies may change s ignif icant ly due to freezing. These measurements are usual ly made with thermis tors or thermocouples , depending on the appl icat ion, wi th the thermistors being more sensi t ive.

Subsur face t empera tures a re ob ta ined e i ther by install ing strings of sensors, in some cases on a permanent basis, in an access hole, or by logging of a n access hole with single or multiple sensors. Both approaches have advantages. Permanent instal la t ions e l imina te the need for an open access hole , reduce the problems of convec t ion tha t may occur in l a rge access holes (Seguin, 1978) and permit rapid logging of t empera tu res at depths which do not change with t ime. Logging with a moving sensor al lows the same equipment to b e u e d at many sites and allows frequent recal ibrat ion.

Jessop and Judge (1974) have described tempera ture measurement methods and in te rpre ta t ion techniques. A common problem in thermal measurements is cor rec t ion for dril l ing disturbances,

Thermal prof i les in the mar ine pe rmaf ros t environment have been descr ibed by Chamberlain et a1 (19781, Osterkamp and Harr ison (19781, Hunter and Judge (1975) and Hunter et al., (1976).

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PROBLEM

NO I ' GEOPHYSICAL YES

" MANIFESTATION? c

MAYBE ' NO +

TEST LYE- I t :S

EVALUATION

+ GEOPHYSICAL AND SPATIAL SCALE OF

VARIATION

FIELD IMPLEMENTATION & INTERPRETATION

GEOTECHNICAL INFORMATION

Figure 7 . An approach to the seleclion of Geophysical methods for solving geotechnical problems, (modif ied f rom Annan and Davis, 3977b).

VI: SUMMARY AND CONCLUSIONS

The appropr i a t e s e l ec t ion and app l i ca t ion of a geophys ica l method or cornbina t ion of me thods fo r permafros t s tud ies o r p roblem-solv ing can be d i f f icu l t even w i th some knowledge of t h e m a n y s y s t e m s . T h e se l ec t ion p rocess is e x t r e m e l y i m p o r t a n t s i n c e i t c a n d e t e r m i n e t h e u t i l i t y of t h e g e o p h y s i c s p r o g r a m , t h e t y p e of r e s u l t s t h a t c a n b e a n t i c i p a t e d , a n d t h e m o s t e f f i c i en t app roach . The i m p o r t a n c e of c o m p l e t e a s ses smen t o f t he geophys ica l me thods and t he i r capab i l i t i e s canno t be unde r s t a t ed . D i scuss ion in th i s s u m m a r y s e c t i o n is based on a f low cha r t mod i f i ed f rom Annan and Davis (3977b), shown in Figure 7.

T h e f i r s t s t e p is a de ta i l ed de f in i t i on of t h e problem to as su re a l l p ro j ec t r equ i r emen t s and o b j e c t i v e s a r e u n d e r s t o o d . T h e p r o b l e m d e f i n i t i o n should include a compi la t ion of a l l ava i lab le b a c k g r o u n d d a t a f r o m t h e s i t e o r r e g i o n t h a t is to be s tudied. Sorne of t h e i m p o r t a n t i n f o r m a t i o n t h a t should be cons idered to ind ica t e whe the r geophys ic s can be u se fu l ly employed and to g u i d e t h e c h o i c e of appropr i a t e t echn ique o r t echn iques is listed below:

1 . S i z e of a r e a to b e s t u d i e d . 2. S i z e of f e a t u r e to be obse rved . 3. A n t i c i p a t e d d e p t h to f e a t u r e to b e o b s e r v e d . 4. Access ib i l i t y o f t he a r ea . 5 . Al l ava i l ab le i n fo rma t ion on ma te r i a l

p r o p e r t i e s a n d s u b s u r f a c e c h a r a c t e r i s t i c s , inc luding seasonal var ia t ion .

6. Prox imi ty and ene rgy l eve l o f exc i t a t ion source r equ i r ed by some pas s ive sys t ems .

7. Proximi ty to p o t e n t i a l n a t u r a l o r c u l t u r a l d i s turbance .

X. Compar ison of p r o j e c t e d cost a n d advan tages fo r geophys ica l and non- geophys ica l a l t e rna t ives .

O n c e t h e p r o b l e m h a s b e e n d e f i n e d a n d a l l v a r i a b l e s h a v e b e e n d e s c r i b e d , t h e n e x t s t e p is to es tab l i sh if a d e q u a t e g e o p h y s i c a l m a n i f e s t a t i o n o f t h e d e s i r e d f e a t u r e e x i s t s . A t t h i s p o i n t , t h e d e t e r m i n a t i o n m a y b e b a s e d o n t h e p r e l i m i n a r y d a t a acqui red dur ing the p roblem def in i t ion . This usua l ly m e a n s a t t e m p t i n g to es tab l i sh if a con t r a s t i n p r o p e r t i e s i s l ike ly be tween the fea ture of in t e re s t and t h e a d j a c e n t m a t e r i a l . A con t r a s t i s r equ i r ed i n e l ec t r i ca l , s e i smic , o r any o the r phys i ca l pa rame te r s t h a t m i g h t b e d e t e c t e d by o n e of the va r ious me thods . The s ign i f i cance of c o n t r a s t i n g p r o p e r t i e s at d e p t h c a n b e e s t a b l i s h e d f o r s o m e m e t h o d s b y t h e o r e t i c a l model l ing , us ing procedures s imi la r to those u sed fo r e v a l u a t i n g a n d a n a l y s i n g t h e d a t a .

Lack o f geophys ica l con t r a s t o r man i fe s t a t ion wou ld sugges t t ha t a geophys ica l app roach to t h e s tudy is not just i f ied. An indicat ion of a geophys ica l m a n i f e s t a t i o n w u l d s u p p o r t t h e n e e d f o r f i e l d t e s t i n g or eva lua t ion . This f ie ld eva lua t ion could be approached in severa l ways . The mos t idea l approach would be to v i s i t t h e i n t e n d e d s t u d y a r e a a n d c o n d u c t a small p i lot f ie ld survey. In many i n s t ances on ly a f e w hour s a r e r equ i r ed to obta in enough in for tna t ion upon which to base j udgmen t s . If t h i s i s no t f ea s ib l e , m e a s u r e t n e n t s c o u l d b e m a d e in a r e g i o n w h e r e t h e s u b s u r f a c e is a n t i c i p a t e d t o b e s i m i l a r o r in s o m e s i tua t ions even labora tory observa t ions can be he lpfu l .

If t h e test eva lua t ion p rov ides p romis ing r e su l t s t h e n m o r e d e t a i l e d a s p e c t s of the p rog ram shou ld be cons idered as ind ica t ed i n t he nex t b lock of t h e f l o w c h a r t . In t h i s s t e p t h e i n f o r m a t i o n f r o m t h e p r o b l e m de f in i t i on and t he f i e ld s tudy w i l l he lp de t e rmine t he th i ckness and ho r i zon ta l spac ing of t h e p a r a t n e t e r of i n t e r e s t . T h e s e c o n d i t i o n s c a n t h e n b e c o m p a t c d w i t h s y s t e m c h a r a c t e r i s t i c s s u c h as sk in depth o r hor izonta l reso lu t ion of the measu remen t . Th i s compar i son w i l l he lp to d e t e r r n i n e if f e a t u r e s can be individual ly d e t e c t c d o r w i l l a p p e a r as a s ing le l a rge r f ea tu re or l ayer . These cons idera t ions a re essent ia l for l ink ing d a t a n c e d s a n d s u b s u r f a c e c h a r a c t e r i s t i c s w i t h f i e l d p rocedure such as spac ing of observa t ions .

If s a t i s f a c t o r y m e t h o d s a n d p r o c e d u r e s for o b t a i n i n g t h e r e q u i r e d d a t a a r e a v a i l a b l e t h e n t h e f i n a l s t e p o n the f l o w c h a r t is appropr ia te . The f ina l s e l e c t i o n of equ ipmen t and deve lopmen t of a f ie ld plan may r e su l t in use o f rnore than one method. The m u l t i p l e use of m e t h o d s is i m p o r t a n t s i n c e it he lps e s t a b l i s h c o n f i d e n c e , a n d c a n c o n t r i b u t e an e x t r a d imens ion t o t he obse rva t ions . Equ ip rnen t cho ice , i nc lud ing da t a ana lys i s p rocedures , w i l l r equ i r e j o in t cons idera t ion in t e rms of the o r ig ina l ob jec t ives of t h e p rogram. Some t echn iques r equ i r e cons ide rab le da t a p r o c e s s i n g w h i l e o t h e r s p r o v i d e r e s u l t s t h a t c a n b e

110

treated directly in a useful quali tative manner. When this much consideration is given to the program design, the end resu l t is a geophysical program which properly meets the geotechnica l requi rements which were originally identified.

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Monastyrev, V.R., Tsibulin, L.G., 1973. Seismic reflection method for subdivision and mapping of permafrost: IInd In te rna t iona l conference on Permafrost , Yakutsk, v. 6, p. 91-97.

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Akimov, A.T,, Mel'nikov, V.P., Frolov, A.D., 1979. Geophysical methods for study of permafrost in USSR (Brief Summary of Published Works of Soviet Researchers): US Army CRREL, Draft Translation 707, 30 p.

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Carg, O.M. and Stacey, P.F., 1973. Techniques used in the de l inea t ion of permafros t in the Scheffervi l le , P.Q, area: Proc, of a Seminar on the Thermal Regime and Measurements in Permafrost , Nat . Research Council, Tech. Mem. 108.

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Geonics Ltd., 1971, EM 16 R (Radiohm) Two-layer interpretat ion Curves: Geonics Technical Note TN-I.

Ghosh, M.K. and Halloff, P.C., 1974. Geoprobe EMR- 14-a new multi-spectral EM induct ion system for del ineat ing depths of permafrost tones: in Nat. Res. Council Can,, Tech. Mem. 113, p. 50-59:

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mechanical and physico-chemical propert ies of some cohes ive soils for ear th and rock- f i l l dams cons t ruc t ion on the Nor th . Pro- ceedings of I-st I n t e r n a t i o n a l C o n g r e s s on Ingeneer ing Geology. Paris. 1970. p.2- 12

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151

THE DESIGN AND CONSTRUCTION OF THE ALYESICA PIPELINE

A. Liguori, J.A. Maple, C.E. Heuer

This presentation is dedicated by the authors to Or. Hal Peyton who was in- volvea originally on the pipeline as a private consultant and subsequently as a senior staff engineer and manager of staff engineering for the Alyeska Pipe- line Service Company. Dr. Peyton was appointed to a delegation of permafrost experts representing the United States in a technical exchange program with the Soviet Union. As a part of this program, he assisted Soviet scientists who visited Alaska. During October 1 9 7 6 as a member of an American delegation comprised of government and industry representatives, he toured the U.S.S.R. to visit research facilities, including the Permafrost Institute in Yakutsk and to inspect major oil and gas fields in the north central regions of that country. Had it not been for his untimely and tragic death, last year, he would be here today talking to you and it is in his memory that we dedicate this presentation.

This report will review some of the trans-Alaska Pipeline project highlights and detail major construction accomplishments. The pipeline was built by Alyeska Pipeline Service Company which is owned by 8 major oil companies or their sub- sidiaries, The 800 mile pipeline carries crude oil from Prudhoe Bay on Alaska's North Slope to Valdez, a year round ice- free port on the south coast of Alaska. From Valdez the oil is transported to market by marine tankers. These operators deliver the oil a short distance to pump Station 1 where the oil enters the pipeline, and is pumped south

1. Formerly: Alyeska Pipeline Service Company, Anchorage, Alaska

Now: Exxon Research and Engineering Company, Florham Park, New Jersey

2 . Alyeska Pipeline Service Company, Anchorage, Alaska

3 . Exxon Production Research Company Houston, Texas

across the flat, treeless tundra of the north slope. About 160 miles south of Prudhoe Bay, the line cxosses the Brooks Mountains through Atigun Pass. At 4 8 0 0 feet this is the highest elevation along the route. The pipeline continues south over forested, rolling hills to the Yukon River, about 3 5 0 miles south of Prudhoe Bay. South of the Yukon River, about 450 miles south of Prudhoe Bay, it by- passes the city o f Fairbanks, Alaska, the second largest community in the state. Further south, it crosses the Alaska Mountain Range through Isabel Pass at an elevation of 3 5 7 5 feet. Nearing the southern end, the line crosses a third mountain range, the Chugach Mountain Range through Thompson Pass, elevation 2750 feet. In these mountains it a l s o winds through the picturesque, but extremely rugged Keystone Canyon before dipping to sea level at Port Valdez.

The final pipeline route and sites for pump stations and terminal were selected after detailed studies o f 8 possible routes and 4 possible terminal locations. The start of the line at Prudhoe Bay was fixed by the location of the North Slope Oil Fields. The choice of sites for the Southern Terminal was based on a variety of factors. They included a purchase to the Port, weather and water conditions, water depth, availability of land for a tank farm, access from the tank farm to docks and the relative merits of the location in terms of the pipeline length, and construction conditions. Once Valdez was selected as the Southern Terminal for the line the general route is further defined by the selection of major mountain and river crossings. An Atigun Pass crossing was chosen in place of Anituvik Pass in the Brooks Range largely because of s o i l conditions and route length, although Atigun Pass is higher than Anituvik, 60 miles to the east. The pipeline route at the Yukon River crossing was determined by the existence of a suitable bridge site.

There was no road north of the Yukon River to Prudhoe Bay so in early 1974,

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convoys o f construction equipment and supplies began moving north across the frozen Yukon River and over trails of snow and ice to build one. The State of Alaska obtained a right-of-way permit from the U,S. Department of the Interior, allowing Alyeska to build a 361 mile road roughly parallel to the pipeline from the Yukon River to Prudhoe Bay. Construction of the road was the first major under- taking of the pipeline project. Work on the road was begun April 29, 1974 and five months, 3 million man-hours, and 2 5 million cubic yards of gravel Later, the road was finished.

In early 1974 the State of Alaska with Alyeska sharing the cost started construction of Alaska's first bridge across the Yukon. The bridge was completed in October 1975. A year later the pipeline was installed on a pipe floatway alongside the bridge. The bridge which towers 17 stories over the river, is supported by 5 piers. The structure is designed to withstand ice forces during spring breakup of the river, winds up to 80 miles an hour, temperatures ranging from -6OoF to 100°F, earthquake stresses slightly more than 5 times higher than excepted engineering levels for that location, and the effects of a 50-year level flood.

The overall construction project has three basic components: the 800 mile pipeline itself, the pump stations, and the Valdez Terminal. Let u5 consider the pipeline first. The pipe was specifically engineered and fabricated for the Alaska Pipeline. Although it will not generally be subjected to unusual forces, the pipeline was designed to sustain all expected hydraulic pressures, thermal forces, and stresses induced by settlement, compaction, earthquakes and weight between supports of the elevated line, including snow and wind loads. Particular emphasis was placed on providing a high degree of assurance that the line will not leak oil although deformed well beyond the limit at which it can successfully transport oil. The pipe, manufactured in three grades and two wall thicknesses, .462 inches and . 5 6 2 inches was alloyed slightly with vanadium and manufactured in a carefully controlled rolling process. The pipe has specified minimum yield strengths of 60, 64, and 7 0 , 0 0 0 lbs per square inch. Different grades of pipe were used in different locations depending upon the pressures and stresses encountered in each location. The pipe was specially coated and given cathodic protection to prevent bacteria- logical, chemical and electrolitic corrosion.

In stable soils, the pipe is buried

in a conventional manner, much as it i s in other parts of the world. Conventional burial was used in areas where soil is either bedrock, thaw stable sand and gravel or thawed soil, or the results of field exploration and analysis demonstrated that soil settlement or instability resulting from thawing would not cause unacceptable disruption of the terrain or damage to the pipeline. Slightly less than half of the pipeline is installed conventionally. Burial depths range from 3 foot minimum cover above the top of pipe, to occasional depths greater than 16 feet, depending on the pipe configur- atior., terrain and soil properties at each location. The pipe was bent conformed to the ditch bottom which was lined with at least 6 inches of crushed bedding material The process of padding material was compacted around and on top of the pipe which was buried 8 to 16 feet below the surface. However, only about 380 miles of the pipeline could be buried in this way. More than one half of the route is underlain by ice rich permafrost that would be unstable if thawed. The pipeline is hot. The oil temperature as it comes out of the ground is approximately 180°F. Heat generated in pumping the oil and friction caused by its flow through the line keep it between 1300F and 140oF at a design rate of 2 million barrels per day.

In areas of ice rich permafrost, especially silts and clays, thawing would create difficult soil stability conditions. In these areas the pipe is elevated aboveground. Installation of the aboveground support system requiring approximately 78,000 vertical support members, called VSM's was completed in July o f 1976. Holes for the VSM were drilled to average depths between 15 and 60 feet. For the majority of the supports, the space around the outside of each VSM was filled with sand slurry mixture which then froze to hold the support in place. Other VSM's were grouted in place and some were regular driven piles. The special thermal devices known as heat pipes were installed in about 80% of the VSM's to maintain the permafrost in a stable condition.

The aboveground pipe is supported on cross beams installed between vertical support members imbedded in the ground. To prevent thawing around the VSM's special thermal devices are installed inside them where required. These devices consist of metal tubes, filled with a refrigerant which vapourizes and condenses thereby chilling the ground whenever the ground temperature exceeds the temperature of the,air. The devices are non-mechanical and self-operating.

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The pipe is fastened to a special shoe, equipped with teflon slide plates that permit movement across the support beam and reduce heat transfer from the pipeline to the supports. In potentially more active seismic zones, extra large supports allow even greater movement. A 1 1 aboveground pipe is insulated to prevent conduction of heat through the supports into the permafrost. Insulation a lso retards oil from thickening during emergency shutdowns, or periods of decreased flow in winter. Pipeline construction was conducted on a 5 0 foot wide gravel workpad. The workpad protected the permafrost and minimized other impacts. In the north- ernmost part of the route, where gravel is scarce, 98 million board feet of foam insulation were installed on the tundra beneath the gravel workpad. The insulation reduced the amount of gravel required.

There are 84 major river crossings on the pipeline. The one across the Tanana River is a 1200 foot long cable suspension bridge. At varied crossings the pipe is jacketed with a 5-inch layer of concrete of is weighted with concrete saddles, each weighing approximately 9 tons.

The second basic component in the Overall construction project is the pumping system that keeps the o i l flowing through the pipeline. Most of the stations are built on stable soils in a relatively conventional manner. IIowever, at five station, 1 , 2 , 3 , 5 , and 6, some structures are erected on refrigerated gravel atop permafrost. Hauls of pipe to circulate cold brine are buried in gravel beneath a plastic foam insulation mat under critical structures to keep the ice rich soi ls frozen and stable.

The third component of the project is the marine terminal at Valdez, where all ocean-going tankers call to pick up the oil and deliver it to market. The Terminal site covers about 1,000 acres and includes storage tanks, docks, a ballast water treatment facility, a power plant, a vapor control facility, office buildings, a warehouse and shop building and the pipeline's operational control centre. Eighteen crude oil storage tanks were built. Fach tank i s 250 feet in diameter, 6 2 feet high, and can hold 510,000 barrels of oil. The tanks have fixed cone shaped roofs to accomodate the heavy snowloads that are standard for the Valdez area. The tanks are sited in pairs within the containment dikes, with a capacity equal to 110% of the total volume of the tanks plus an additional 2 foot allowance for surface water which may be impounded within the area.

Communications €or pipeline operations is performed via a microwave system utilizing 41 microwave stations. This network is backed up be a satellite communications system.

Dr. Maple will discuss some of the challenging design construction hurdles overcome by the Trans-Alaska Pipeline. The first and foremost problem was protection of the pipeline in areas where permafrost is not thaw stable. This was accomplished by elevating the pipeline on pile bents to avoid transfer of heat from the hot oil pipeline to the soil. A flexible system incorporating trapezoidal track expansion loops was selected over a fully restrained system as the flexible system provides greater operating reliability through relative insensitivity to settlement. The line is anchored at intervals of 800 to 1800 feet and is supported between at 60 foot intervals on sliding friction supports with low friction materials.

Sliding shoes also present a solution to the problem of ground motion due to earthquakes by decoupling the pipeline from the ground motion. The maximum ground motion experienced was par f o r an 8 . 5 Richter magnitude earthquake and associated with seismic activity along the route are three faults. On the Denali Fault the pipe was placed on beams to grade. The beams were 45 feet long and the pipe positioning was designed to account for a 20 foot right lateral by 5 foot dip fault movement. The pipe is positioned somewhat peculiarly on the beams, to take maximum advantage o f the location of the fault and the length of the beams, so that the beam length could be minimized.

The McGinnis Glacier Fault Zone presented additional problems with up to 12 feet of scour and alluvial fans. Two alluvial fans, one on Castner and one on Lower North Creek were crossed. The scour depth plus the requirement for elevating the pipeline several feet aboveground due to icing conditions required an additional pile in each pile bed to accomodate the lateral loads, and fill in the system by friction when the pipe moves. To support this all three piles wexe tied together making a triangular trust work.

Terrain presented construction challenges at several locations along the pipeline. These challenges seemed almost insurmountable at three locations. Atigun Pass in the Brooks Range, Thompson Pass in the Chugach, and traversing the east wall at Keystone Canyon near Valdez. Atigun Pass has a critical stretch of pipeline about 165 miles south of Prudhoe

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Bay. The currents of large, destructive slush flow avalanches in this area prevented aboveground construction making it necessary to place the pipe below ground. The design required burial in difficult ditching areas and resulted in a special thermal design utilizing new materials and procedures and requiring unusual construction techniques. The special thermal design required that the pipe be sealed and buried in an insulated box with wall thickness of 21 inches and supported on a 12 inch concrete slab to limit the 30 year thaw below the box to approximately L foot with no significant settlement. The pipe was placed in the box and a cement gravel grout was poured filling the space between the pipe and the insulation. The insulation and grout were required to seal around the pipe so that infiltration of groundwater could be eliminated which would then be welled to the pipe and could possibly cause additional thawing of the ground. This method was used on approximately 6,000 feet o f pipe in the Atigun Pass area.

Keystone Canyon, 18 miles northeast of the Valdez Terminal was considered one of the more challenging sections of the pipeline route. The pipeline construction above the steep canyon was expected to be extremely difficult because of the rugged alpine terrain. Constructing the pipeline above the canyon, which seemed easier, would have required digging up an existing state highway which extends down the bottom of the canyon, caused lengthy road closures and public in- convenience. Alyeska decided to go above the high east wall of the canyon. The danger of rock and snow slides prevented anchoring the pipeline on the canyon walls. Small helicopters were used to ferry work crews to several points along the top of the canyon and the Sikorsky Skycrane was used to Lift equipment. Where equipment was too heavy to be lifted in it was broken down and then reassembled on top of the canyon. A rock crushing plant was built at the tope of the canyon to manufacture backfill material to eliminate the need to truck gravel up the steep slopes at either end of the canyon where the pipeline drops about 800 feet on a 60% slope. If gravel had been trucked in, it would have had to be dragged up the steep slopes. Forty thousand yards of material were used to backfill the pipe in the canyon. The Keystone Canyon is 4 miles long with a 2,500 foot section at the north face which rises 8 4 0 feet and a 2,300 foot section which drops 820 feet on the south face.

In Thompson Pass which is Located about 2 0 miles northeast of Valdez, it is

4,000 feet long and it plunges 1800 feet for that 4,000 feet. It has slopes of up to 125% and because of the severity of these slopes a special cableway was built to fly pipe up to the locations. Each section of pipe, which is 80 feet long, weighed about 10 tons. It was attached flat and lifted up the mountaintits position determined either'by remote control or by coordinated control with radios and welded into place. Welding, X-raying, or just standing on the steep slopes themselves is a challenge and on such sessions welders harnessed themselves to a chain attached to the pipe and literally hung in midair as they worked. While some crews were rushing to complete pipe installation, backfill crews found themselves facing a race against worsening weather conditions including heavy snowfalls. To facilitate backfilling two numadic placing units were utilized. At three seperate locations in the upper portion of the pass where slopes were greater than 5 5 % , a cement stabilized backfill was required to bind the pipe into the trench. Peter DeMay, former Vice President, Project Management €or Alyeska referred to the building of the Thompson Pass section as one of the greatest challenges of the entire project. It represents one of the most significant construction accomplishments of the people building the pipeline.

Environmental protection presented its share o f challenges to the design and construction of the pipeline too. Two notable examples were provision for caribou crossings and ice rich permafrost and a requirement to utilize approximately 5 miles of snow workpad to minimize the use of gravel on the north slope. In two locations where the pipeline intersects the migration route of the Nelchina herd, refrigerated burial was used for a total length of 4 miles in lieu of belowground pipeline.

At 23 locations along the route a 60 foot segment of pipe was buried in an-insulated box with heat pipes installed for thermal protection and to limit thaw settlement to acceptable levels of approximately 2 feet. Because this section is located in aboveground pipe the flex- ibility of the line can accommodate settlement that is much greater than if that section had been buried.

Construction of the pipeline from a snow workpad was difficult because it required working during the winter season. Further difficulty was caused by the lack of available snow in the Arctic which required the manufacture of artificial snow to complete construction of the workpad. Construction on a snowpad is ex-

pensive but it can be accomplished without disturbing the tundra vegetation. Construction i s slowest in the winter season and the time available is limited by the onset of breakup in the arctic.

Mr. Heuer will discuss in greater detail the utilization of heat pipes in pipeline construction. During construction and design of the pipeline many problems were encountered that involved the thermal protection of permafrost. Where possible these problems were avoided by route selection or mode selection, either buried or elevated. Where problems could not be avoided they were often solved using heat pipes. A heat pipe is a closed tube that transfers heat by natural conduction with change of phase and operates only during the winter when the air temperature is colder than the soil temperature. Recause natural conduction is involved heat transfer is in only one direction, from the ground to the atmosphere, and since a change of phase is involved, heat transfer is efficient even at very low temperature differences. Properly designed heat pipes can provide enough cooling during the winter to more than offset warming during the summer. The Alyeska heat pipes have an internal diameter of I$ inches and range in length from 2 8 to 7 5 feet. Ammonia is the worst fluid. Alyeska heat pipes were designed to transfer a minimum of 12 watts per foot of belowground em- bedment for a 3OF temperature difference across the heat pipe. Approximately 120,000 heat pipes were installed along the pipeline, most in VSM. All VSM receive two heat pipes although in many cases only one heat pipe was actually needed. This provided redundancv in case of a heat Dine

placed as closely as possible to the VSM wall because the metal wall o f the VSM acted as a belowground fin to improve heat transfer with the soil. The soil represented the major thermal resistance in the VSM soil system. The heat pipes had to extend within a minimum of 3 feet at the bottom of the VSM.

There were several reasons why heat pipes were installed in VSM. They were used to maintain initially frozen soil, frozen to cool frozen soil well below the freezing temperature, to freeze initially thawed soil, and to provide for the radial freezeback of the active layer. The specific reasons why heat pipes were installed in a particular VSM depended on the local soil conditions, in general heat pipes axe less effective in coarse grained soils where there is less unfrozen moisture below the freezing temperature and there is a higher probability of groundwater flow problems. The use of heat pipes allowed cooler soil temperatures which permitted higher frozen strengths when calculating VSM load capacities. The heat pipes also reduced jacking and down drag to a negligible amount and could prevent soil liquefaction and slope instability problems. Installing heat pipes did significantly complicate construction, although they allowed much shorter VSM embedments than compared to conventional piles and therefore were cost effective. In some cases where the soils were especially poor, heat pipes provided the only design alternative.

Heat pipes were used in other situations other than VSM and direct support of the elevated pipeline. How- ever, the same general geometry of the

Aluminum radiators we;e press fittedz onto the upper portion o f the heat pipe, the radiators were either 4 feet or 6 feet long, depending on the length of the heat pipe. It was important to size the radiators correctly to allow for efficient heat transfer. A conservative approach was taken in that still air conditions were assumed when determining the heat transfer coefficient, although it was known that low wind speeds even 1 ox 2 miles per hour could more than double the heat transfer coefficient. The heat pipe extends-about 6 inches above the top of the radiator. This provides a gas trap should non-condensing gas form inside the heat pipe. In this way it will collect in the gas &rap rather than block the radiator. The VSM is filled with saturated sand slurry up to the ground level, the aboveground portion was not filled with the saturated slurry to avoid the potential of damage to the VSM when the slurry froze and possibly expanded. Heat pipes were

design and construction. An example is a bridge pier being protected by four free-standing VSM. The spacing is determined to provide thermal protection to all the load bearing piles for the bridge pier. Five different bridges are protected by freestanding VSM.

At a buried animal crossing free- standing VSM as well as insulation are used to prevent excessive thaw settlement. Fourteen different crossings were constructed in this manner. At a road crossing similar to a buried animal crossing, insulation and heat pipes were used to prevent excessive thaw settlement. The crossing is about 500 feet long.

At an aboveground valve site the valve building contains the power generation and communications equipment for the valve. In front of the building propane tanks were installed which are used as fuel for the power generation

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equipment. Heat pipes are used to support both the valve building and the buried propane tanks.

At a communications tower around the equipment building the heat pipes are installed in the external slurry o f the piles supporting the building. To the left at the base of the tower leg are long piles which are similar in operation to heat pipes. The reason there are long piles there instead of heat pipes is because there was a different contractor; there were two different contractors at the site,

An unique installation resulted from a reevaluation by Alyeska of the soil conditions after the pipe had already been buried. Alyeska decided that to meet government stipulations remedial work was required. The pipe was buried between the two right-hand row of free- standing VSM. There are 2 2 free-standing VSM on a 100 foot section of pipe, The free-standing VSM and insulation were used to prevent excessive thaw settlement and slope instability.

The heat pipe and thermal VSM design were developed using extensive computer simulations, laboratory test, and field tests. Three different field tests were conducted using heat pipes. The first two used commercially available heat pipes but the third test used protype heat pipes. This slide shows the protype heat pipe test site outside Fairbanks. An actual 150 foot section of the pipeline was constructed. The soil conditions at the site are ice rich organic silt with the initial soil temperatures below the active layer ranging from 30 to 31°F. This is the type of soil conditions where good heat pipe performance is essential because if the soil does warm too close to 32O~or thaw there will be a drastic change in the mechanical properties of the soil. Thermistor strings were installed at the test site near 4 VSM, beneath the gravel pad and beneath the undisturbed tundra. Data collection began in October, 1 9 7 4 when the heat pipes were installed and is still continuing but on a reduced basis. After one year of operation, at the end of summer, 1 9 7 5 , if the warmest VSM is considered and looking at the average temperature below the design active layer, that temperature is 1°F cooler than the corresponding temperature below the undisturbed tundra and 14O cooler compared to beneath the gravel pad. By the summer of 1 9 7 7 , that is 3 complete years of operation, there had been an additional 8/100F of a degree cooling, again looking at the warmest VSM compared to the undisturbed tundra. The temperatures at a11 the monitored VSM ranged from 27OF to 280F.

These are average temperatures below the design active layer taken at the end of summer so they are the warmest temperatures ever occurring along the VSM. Minimum temperatures during the winter could be as low as -10oF. For this site the data indicate that the standard VSM design is quite conservative in that the standard design assumes an average temperature over the entire life of the pipeline of 31.5OF.

Extra care was taken during design development to insure the long-term reliability of the heat pipes. A rigorous manufacture qualification program was conducted which included accelerated life testing of heat pipes to insure that excessive non-condensing gas would not be generated inside them. Despite the care taken, it was inevitable that at least a small percentage of heat pipes would fail and so a system had to be devised to detect and replace those failures. There are several different failure mechanisms. There could be only a leak of the working fluid, ammonia, generation of non-condensing gas, or poor thermal coupling between the pressed on radiator and the heat pipe. Regard- less of the failure mechanism the result would be a decrease in radiator temperature during the winter and so it was chosen as the failure detection parameter and an air born infrared system was developed to measure temperatures during the winter.

Data were collected on standard black and white video tape. The advantage was that the data could be evaluated in the helicopter as they were being collected. It also provided for immediate data analysis once collection was completed. The data were taken during low temperatures when the heat pipes were operating near their peak and this had to be done during twilight or darkness because the sun shining on the radiators could provide anomalous temperature condition, Therefore, two men were sent in a helicopter in the middle of winter in the dark to monitor the heat pipes.

Heat pipes can become deficient when a heat pipe is slightly darkened, this means that it is slightly cooler. In the optical system of the infrared scanner were built in t w o black bodied references. The dark vertical strip represents the cold temperature reference, for example at - 4 2 0 F . The white vertical strip on the other i s the hot temperature reference, for example at -160F. The intermediate temperatures are shown by various shades of grey. It could be determined quantitatively

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by linear interpolation on the output voltage from the system. The data were analyzed and the video tape was visually scanned looking fo r such anomalies. When one was spotted the temperature of the deficient radiator was compared to the temperatures of the other three VSM, the other three radiators in the beng. The average of these three radiators was considered to represent a properly functioning heat pipe and the temperature of the deficient heat pipe was also compared to a reference radiator. The reference radiator is a 2 foot section of heat pipe on a pipe stub at the same elevation as the standard radiators. The reference radiator is not attached to a working heat pipe, its temperature represents a completely failed heat pipe. If this comparison met certain criteria, then a heat pipe was replaced. A major problem in doing this was actually locating the VSM in the field and to do this a sophisticated ground marking system was developed. Deficient heat pipes are determined by counting anchors and then intermediate bents on the video tape after which the same thing is done in the field.

T o replace a heat pipe the deficient one is simply cut off below the bottom o f the radiator and a smaller replacement heat pipe can be slipped inside the standard one. The replacement heat pipe has an internal diameter o f 1 inch compared to the standard heat pipe of 1-4 inches and is about 90% as efficient as a standard one. The annulus between the two heat pipes i s filled with an ethyline, glycol and water mixture after which the two heat pipes are welded together. Two surveys, t w o infrared monitorings of the elevated line were conducted in the winter of 1976/77. A s a result of that monitoring 120 heat pipes were replaced. A few additional failures were detected by 1977/78 monitoring. The number to be replaced has still not been finally decided, although it will be quite small, perhaps in the order of 10 to 15,

Approximately 150 thermistor strings have been installed near thermally sensitive pipeline structures, most of which are VSM. Data collection was started in 1976 and continues on a regular basis. Thus far the data indicate that the heat pipes are performing adequately. This is despite the unusually warm winter of l.976/77, immediately before pipeline startup. For example, in that winter the average January temperature in Fairbanks represented one warm winter out of 100.

These VSM were installed in initially thawed soil but had one year of heat pipe operation. The inspection holes allow direct visual verification of the freeze bulb generated around the VSM. It was found that the freeze bulb radius was 3+ to 4 % feet from the VSM centerline which is consistent with computer calculations. Skin melting can occur which i s the local depression o f the active layer in the immediate vicinity o f the VSM caused by heat conduction down the metal VSM wall. It may be as much as an additional 1% ft below the local active layer near the VSM.

The development of natural resources has been greatly stimulated in recent years and this has led to increased interest in permafrost science and engineering. The Trans-Alaska Pipeline has played a major role and will undoubtedly continue to do so in the years ahead.

During construction large diameter holes were drilled next to selected VSM.

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EXPERIMENTAL RESEARCH ON THE PRINCIPAL MECHANICAL PROPERTIES O F F R E E Z I N G AND FROZEN

SOILS I N CHINA ( A REVIEW)

Chen Hsiao-pai and Wu Tzu-wang, Research I n s t i t u t e o f G l a c i o l o g y a n d Cryopedology , Academia S i n i c a , Lanchow, The People ' s R e p u b l i c of China

ABSTRACT

T h i s i s a review of t h e r e s u l t s of e x p e r i m e n t a l r e s e a r c h o n t h e m a i n m e c h a n i c a l p r o p e r t i e s of f r e e z i n g a n d f r o z e n soils r e l a t i n g t o t h e f o l l o w i n g a s p e c t s : f r o s t h e a v i n g i n t h e ac t ive l a y e r ; v a r i o u s t y p e s of f r o s t h e a v i n g f o r c e s a n d t h e i r e f f e c t s ; e f f e c t o f g r o u n d t e m p e r a t u r e , water c o n t e n t and ice s e g r e g a t i o n o n a d f r e e z i n g f o r c e s ; " i n s i t u " m e t h o d of m e a s u r i n g t h e b e a r i n g c a p a c i t y of f r o z e n g r o u n d a n d o t h e r f a c t o r s t h a t i n f l u e n c e t h a w c o n s o l i d a t i o n c h a r a c t e r i s t i c s o f f r o z e n g r o u n d a n d t h e i r r e l a t i o n t o t h e b a s i c p h y s i c a l p r o p e r t i e s o f f r o z e n soils.

INTRODUCTION

I n t h e e c o n o m i c d e v e l o p m e n t of t h e e x t e n s i v e n o r t h e a s t e r n a n d n o r t h w e s t e r n r e g i o n s o f o u r c o u n t r y , t h e m e c h a n i c a l p r o p e r t i e s o f f r o z e n soils are becoming a s i g n i f i c a n t factor i n c o n s t r u c t i o n i n areas of f rozen g round .

A s w e know, most s t r u c t u r e s i n t e r a c t w i t h t h e ac t ive l a y e r , a n d w h i l e t h e g r o u n d i s f r o z e n t h e y a re b o t h s u b j e c t e d t o h e a v i n g a n d t h e a c c o m p a n y i n g p r e s s u r e . When f o u n d a t i o n s s u c h as p i l e s o r columns a re b u r i e d i n p e r m a f r o s t , t h e a d f r e e z i n g s t r e n g t h b e t w e e n t h e m a n d t h e soil n o t o n l y p r o v i d e s b e a r i n g , b u t a l so o f f s e t s t h e h e a v i n g p r e s s u r e s i n t h e a c t i v e l a y e r ; w i t h c o l u m n f o u n d a t i o n s , a n d e s p e c i a l l y p i e r s and s t r i p f o u n d a t i o n s , t h e correct b e a r i n g c a p a c i t y i s t h e most n e c e s s a r y b a s i c d e s i g n data . B e c a u s e t h e r h e o l o g y o f ice d e t e r m i n e s t h e c r e e p p r o p e r t i e s of f rozen g round unde r l o a d a n d t h e r e l a x a t i o n effect d e f o r m a t i o n , i n v e s t i g a t i o n s of t h e above problems must i n c l u d e t h o s e of o b s e r v i n g t h e e n v i r o n m e n t a n d c h a n g e s i n it.

I f t h e f o u n d a t i o n soil b e n e a t h a h e a t e d b u i l d i n g o n p e r m a f r o s t i s a l l o w e d t o thaw, t h e i n c r e a s e i n d e p t h of thaw aue t o t h e d a i l y a c c u m u l a t i o n of h e a t , w i l l r e s u l t i n t h a w s e t t l e m e n t a n d r e c o n s o l i d a t i o n . T h e r e - fore a n t i c i p a t e d s e t t l e m e n t m u s t b e p r e d i c t e d at t h e d e s i g n s t a g e .

S i n c e 1 9 6 5 , a series of s y s t e m a t i c e x p e r i m e n t s a n d f i e l d o b s e r v a t i o n s o n t h e basic m e c h a n i c a l p r o p e r t i e s of f r o z e n g round have been success fu l ly carr ied o u t i n d i s t r i c t s s u c h a s C h i l i e n M o u n t a i n s , t h e g r e a t e r K h i n g a n M o u n t a i n a n d a l o n g the Ch ingha i -T ibe t H ighway . Labora to ry r e s e a r c h w a s a l so done a t t h e same time. V a r i o u s a g e n c i e s c o n n e c t e d w i t h t h e n a t i o n a l r a i l w a y s , h i g h w a y s , c o n s t r u c t i o n , water c o n s e r v a n c y a n d f o r e s t r y h a v e a l l made many i n v e s t i g a t i o n s . I n t h i s p a p e r , w e w i l l describe a n d a n a l y z e some of t h e r e s u l t s o b t a i n e d f r o m tests a n d o b s e r v a t i o n s o n f r o s t h e a v i n g , f r o s t h e a v e p r e s s u r e s , b e a r i n g c a p a c i t y of soils and thaw set t lement c h a r a c t e r i s t i c s . The m a i n r e s u l t s as m e n t i o n e d i n t h i s a r t i c l e a re t h e co l lec t ive work of t h e g r o u p d o i n g r e s e a r c h o n s o i l m e c h a n i c s i n t h e C r y o p e d o l o g y R e s e a r c h D i v i s i o n , Lanchow I n s t i t u t e of G l a c i o l o g y and Cryopedology, Academia S i n i c a .

I n o r d e r t o o b t a i n f u r t h e r k n o w l e d g e o n t h i s s u b j e c t , work i s s t i l l b e i n g c a r r i e d o u t .

FROST HEAVE AND FROST HEAVE PRESSURE

F r o s t Heave

The e f fec t of t h e h e a v i n g of s o i l d u r i n g f r e e z i n g is t h e r e s u l t , n o t o n l y of t h e v o l u m e t r i c a l s w e l l i n g of water t h a t f r e e z e s i n t h e v o i d s of t h e o r i g i n a l g r o u n d , b u t a lso t h e c o n t i n u a l m i g r a t i o n and accumula t ion of water t h a t becomes ice when f r o z e n t o w a r d t h e f r e e z i n g f r o n t i n t h e u n f r o z e n z o n e .

Tests show t h a t when t h e water c o n t e n t i n t h e soil r e a c h e s a c r i t i c a l v a l u e , t h e s w e l l i n g of t h e soil u n d e r g o i n g f r e e z i n g becomes n o t i c e a b l e ; t h i s c r i t i ca l limit i s ca l led t h e i n i t i a l w a t e x c o n t e n t of

frost h e a v i n g W;'). T a b l e 1 shows Wo v a l u e s fo r s e v e r a l t y p e s o f s o i l under l abora tor ia l t e s t i n g .

160

N a m e Loam

--"-- wo% I I2 - l7

Loam

10-14

Bouldery Clayey Soil

S o i l c o n t a i n i n g C o n t a i n i n g S i l t a n d B o u l d e r y

G r a v e l C l a y S o i l * Sand

* Weight o f g r a i n d i a m e t e r < 0 . 0 0 5 mm l e s s t h a n 128 of o v e r a l l w e i g h t

T a b l e 1 Test Value Wo o f Severa l Types of S o i l

F o r c l a y e y s o i l :

Wo 0 . 8 4 W P (1)

where W - water c o n t e n t a t t h e p l a s t i c P l i m i t .

I n a c losed sys t em and €or t h e ac t ive l a y e r i n t h e p e r m a f r o s t r e g i o n w h i c h is l a c k i n g i n g r o u n d w a t e r r e c h a r g e , a l i n e a r e q u a t i o n c a n be u s e d a p p r o x i m a t e l y t o g i v e t h e mean f r o s t heave r a t e (Wu Tzu-wang, Chang Chia-yi , Wang Yan-qing and Shen Chong-yen, 1 9 7 2 ; Tong Shang-chiang and Wang Yan g i n g , 1 9 7 7 ) .

= K ( W - Wo) ( 2 )

i n w h i c h w - mean water c o n t e n t i n t h e a c t i v e l a y e r ;

K - e m p i r i c a l c o e f f i c i e n t r e l a t i n g t o s o i l p r o p e r t y .

I t i s p a r t i c u l a r l y n o t e w o r t h y t h a t i n t h e ac t ive l a y e r i n areas of s e a s o n a l f r e e z i n g , a s well as i n p e r m a f r o s t r e g i o n s , t h e r e e x i s t s a main zone of f r o s t heave , as shown i n F i g u r e 1 (Chen Hsiao-pai , 1 9 7 2 ) . I n t h e p e r m a f r o s t a c t i v e l a y e r ( F i g u r e l a ) t h e m a i n f r o s t heave zone i s s i t u a t e d i n L/3 t o 2 /3 of t h e t h i c k n e s s o f t h e a c t i v e l a y e r a n d t h e a m o u n t of frost heave exceeds 80 -90% o f t he t o t a l ; below t h i s t h e f r o s t h e a v e i s minimal; from t h e r e downward, n e a r t h e p e r m a f r o s t t ab l e (still p e r t a i n i n g t o t h e f r e e z i n g f r o n t ) i s t h e sub f ros t heave zone . Accord ing t o d a t a f r o m t h e I n s t i t u t e of S c i e n t i f i c R e s e a r c h o n Low Tempera tu re Cons t ruc t ion , He i lungk iang P r o v i n c e , i n areas o f s e a s o n a l g r o u n d f r e e z i n g , a t o n e - t h i r d of t h e f r o s t d e p t h of t h e s u r f a c e soil l a y e r , t h e frost heave is a b o u t 6 5 % of t h e t o t a l f i g u r e , a n d a t 1 / 3 t o 4 / 5 of t h e f r o s t d e p t h , it is a b o u t 3 0 % ; t h e m a i n f r o s t h e a v e bel t i s located

w i t h i n t h e r a n g e of 2 / 3 o f t h e t o t a l d e p t h ; a n d t h e z o n e w i t h n o h e a v e u s u a l l y l i e s a t t h e b a s e o f t h e l a y e r h a v i n g t h e g r e a t e s t s e a s o n a l f r o s t a c t i v i t y .

I n o r d e r t o r emove t he e f fec t of f r o s t h e a v e o n b u i l d i n g s , c l e a n d r y s a n d ( o r s a n d y g r a v e l ) is used t o r e p l a c e f r o s t s u s c e p t i b l e so i l . Sometimes, good r e s u l t s a re a c h i e v e d b u t , o n o t h e r o c c a s i o n s , it p r o v e s t o be t h e c o n t r a r y . I n 1 9 7 4 , a tes t by Chen Hsiao-pail showed t h a t t h e i d e a l r e s u l t c o u l d o n l y be o b t a i n e d when a r e l a t i v e l y p e r m e a b l e l a y e r l i es a t t h e b a s e of t h e e x c h a n g e l a y e r a n d s u r p l u s pore water has been removed under t h e i n f l u e n c e of a f r e e z i n g p r e s s u r e g r a d i e n t .

F r o s t H e a v e P r e s s u r e o n a F o u n d a t i o n

When expans ion due t o f r o s t h e a v e i s r e s t r i c t e d , t h e f r e e z i n g s o i l b e g i n s t o e x e r t a n u p w a r d l i f t i n g f o r c e (sometimes it may be a c o m p r e s s i v e force) o n t h e s t r u c t u r e or f o u n d a t i o n ; it is s i m p l y cal led f r o s t h e a v i n g c o m p r e s s i v e p r e s s u r e (or f r o s t h e a v i n g f o r c e ) . A c c o r d i n g t o i t s r e l a t i o n t o t h e f o u n d a t i o n s u r f a c e , it c a n be c l a s s i f i e d a s fo l lows (Chen Hsiao-pai l Tong Shang-chiang and She Qin-sheng, 1972; Chen Hsiao-pai and Tong Shang-chiang, 1977) :

1. When t h e d i r e c t i o n of h e a t f l o w Q is p a r a l l e l t o t h e f o u n d a t i o n s u r f a c e as shown i n F i g u r e 2a, t h e r e e x i s t s a l a t e ra l f r o s t h e a v i n g p r e s s u r e T a t t h e s i d e s of t h e f o u n d a t i o n and a frost h e a v i n g p r e s s u r e u1 normal t o t h e base

of t h e f o u n d a t i o n .

2 . When t h e d i r e c t i o n o f h e a t f l o w Q i s d i a g o n a l t o t h e s i d e of t h e f o u n d a - t i o n ( F i g u r e 2 b ) , b e s i d e 'c' and 01, t h e r e

i s a l a t e r a l f r o s t h e a v i n g p r e s s u r e n o r m a l t o t h e s i d e of t h e f o u n d a t i o n ; it is a l so

161

c a l l e d t h e l a t e r a l c o m p r e s s i v e t h r u s t 0 a t t h e s i d e of t h e f o u n d a t i o n . I t is t h i s f o r c e t h a t c a u s e s t h e c o n c a v e d e f o r m a t i o n o f b u i l d i n g f o u n d a t i o n s ( p a r t i c u l a r l y s t r i p f o u n d a t i o n s ) .

Tangen t i a l Frost Heaving Fosce

l. Process of development . Figure 3 shows t h e l i n e s o f t a n g e n t i a l f o r c e s a c t i n g on a c o n c r e t e p i l e , i n r e l a t i o n t o g r o u n d t e m p e r a t u r e i n a permafros t reg ion where t h e s o i l l a y e r i s f rozen . On the who le , t h e y c a n b e d i v i d e d i n t o t h r e e s t a g e s (Chen Hsiao-pail 1975; Chen Hsiao-pai and Tong Shang-chiang, 1977) .

S tages o f g radual change - Frozen p e n e t r a t i o n i s abou t 3 0 c m ; ground temper- a t u r e g r a d i e n t dO/dh = 0.1-0 .2°C/cm; o v e r a l l f r o s t h e a v i n g f o r c e g r a d u a l l y i n c r e a s e s .

S t age o f ab rup t rise - Frozen depth f rom 30 cm down t o t h e e n t i r e main f ros t heave zone . The peak va lue o f the o v e r a l l f r o s t h e a v e f o r c e o f t e n a p p e a r s a t t h e l o w e r limit o f t h e main f r o s t h e a v e z o n e . I n t h i s s t a g e , t h e g r o u n d t e m p e r a t u r e g r a d i e n t i s c o m p a r a t i v e l y s m a l l , g e n e r a l l y dO/dh = 0.06-0.01°C/cm. L a r g e q u a n t i t i e s of water a c c u m u l a t e i n t h e s o i l l a y e r , a n d t h e f r o s t h e a v e f o r c e r ises a b r u p t l y . B e c a u s e o f t h e g r e a t e r r h e o l o g i c a l p o t e n t i a l of f i n e g r a i n e d soils, where t he i nc reas ing frost heave force i s no t s t rong enough t o resist c r e e p , phenomena o f r e l a x a t i o n stress a p p e a r l o c a l l y . I n c o a r s e g r a i n e d s o i l s , it is n o t so obvious.

S t a g e o f r e l a x a t i o n - When t h e f r o s t h e a v e f o r c e i n c r e a s e s , s l o w l y o r e v e n s t o p s , t h e r h e o l o g i c a l phenomenon becomes the dominan t func t ion . Th i s shows t h a t t h e r e l a x a t i o n p r o c e s s o f f r o s t h e a v e force proceeds w i th time. I n f i n e g r a i n e d soil, e s p e c i a l l y ice r i c h s o i l s , t h i s s t a g e i s p a r t i c u l a r l y c o n s p i c u o u s .

Observa t ion of Chen Hs iao -pa i i n 1974 d i scove red t ha t when t h e f r o s t h e a v e fo rce deve loped t o t h e s t a g e o f r e l a x a t i o n a s shown by po in t N i n F i g u r e 3 , t h e t o t a l f r o s t h e a v e f o r c e r e a c h e d 7 9 0 0 k g i n s t a n - t a n e o u s l y . I f t h e t o t a l f o r c e a c t i n g o n a c o n c r e t e p i l e were t o b e s u d d e n l y d i s e n g a g e d t o 1150 kg (see F i g u r e 4 ) , a d e f o r m a t i o n o f r e s i l i e n c e S=13 mm appeared a t t h e t o p o f t h e p i l e , a n d t h e o v e r a l l f o r c e i n c r e a s e d c o n t i n u a l l y a f t e r w a r d s ; it reached 3190 kg i n 8 h o u r s a n d r o s e t o 3670 kg i n 3 6 hours ; f rom then t o 50 hours , the change s lowed down a n d t h e l i n e became smooth.

Th i s phenomenon shows t h a t : F i r s t , u n d e r t h e a c t i o n o f f r o s t h e a v e p r e s s u r e , t h e f r o z e n soil a r o u n d t h e p i l e i s under

t h e f i e l d o f i n f l u e n c e o f c o m p r e s s i v e stress. Once t h e stress is p a r t i a l l y removed, t h a t p a r t of t h e e l a s t i c d e f o r m a t i o n o f f r o z e n s o i l c a n r e c o v e r immediately.

second, due t o t h e i n c r e a s e o f f r o s t h e a v e p r e s s u r e a r o u n d t h e p i l e , t h e f r e e z i n g t e m p e r a t u r e o f w a t e r d r o p s c o r r e s p o n d i n g l y a n d t h e t h i c k n e s s o f t h e w a t e r f i l m d e c r e a s e s . When t h e stress is p a r t i a l l y removed t r a n s i e n t l y , t h e f r e e z i n g p i n t rises, t h e u n f r o z e n w a t e r i n t h e s o i l w i l l p a r t i a l l y f r e e z e . S i m u l t a n e o u s l y , t h e water of t h e u n f r o z e n w a t e r f i l m w i l l m i g r a t e t o w h e r e t h e f i l m is t h i n n e r a n d f r e e z e . T h i s w i l l c a u s e t h e f r o s t h e a v i n g f o r c e t o r e c o v e r p a r t i a l l y .

2 . D i s t r i b u t i o n w i t h d e p t h . L e t t h e v e r t i c a l c o o r d i n a t e h b e t h e f r o s t d e p t h , a n d t h e h o r i z o n t a l c o o r d i n a t e r e p r e s e n t t h e mean t a n g e n t i a l f r o s t h e a v e f o r c e T c o r r e s p o n d i n g t o a c e r t a i n d e p t h of f r o s t heave. Then w e c a n o b t a i n a s t a t i s t i c a l r e l a t i o n s h i p o f v a r i o u s o b s e r v a t i o n a l d a t a f o r p e r m a f r o s t r e g i o n s as shown i n F i g u r e 5 (Chen Iisiao-pai and Tong Shany-chiang, 1 9 7 7 ) . O b v i o u s l y , i n t h e f i r s t s t a g e o f deve lopmen t o f f ro s t heave p re s su re , t he mean p res su re changes ve ry l i t t l e through t h e f r o z e n l a y e r . When it d e v e l o p s i n t o t h e s e c o n d s t a g e , t h e c o r r e s p o n d i n g mean f r o s t h e a v e p r e s s u r e i n c r e a s e s , a b r u p t l y wi th depth . A f t e r it r e a c h e s t h e p e a k v a l u e it e n t e r s t h e r e l a x a t i o n s t a g e . A t t h i s time, t h e mean frost h e a v i n g p r e s s u r e t h r o u g h t h e f r o z e n l a y e r r a p i d l y d e c l i n e s . The s t a t i s t i c s o f many f i e l d o b s e r v a t i o n s show t h a t t h e g r e a t e s t d e p t h of f r o s t i s between 1 2 0 c m t o 150 c m . The h i g h e s t mean t a n g e n t i a l f r o s t h e a v i n g f o r c e s appear to be be tween 50 and 1 0 0 c m and t h i s d e p t h c o r r e s p o n d s t o t h e main f r o s t heave zone.

3 . In f luence o f mo i s tu re . Tests show t h a t when t h e w a t e r c o n t e n t o f t h e s o i l e x c e e d s Wo, t h e t a n g e n t i a l f r o s t h e a v e f o r c e i n c r e a s e s a s t h e w a t e r c o n t e n t i n c r e a s e s . F i g u r e 6 shows t h e r e l a t i o n s h i p be tween t angen t i a l f ro s t heave fo rce and water content (Shen Shong-yen, Chang Chia- y i , Wang Yan-qing, and Wu Tzu-wang, 1 9 7 2 ) . From Figure 5 w e know t h a t t h e t a n g e n t i a l f r o s t h e a v e f o r c e would be g rea tes t when t h e w a t e r c o n t e n t r e a c h e s a c e r t a i n l i m i t , b u t it d e c r e a s e s a f t e r w a r d s . Under l a b o r a t o r y c o n d i t i o n s , a maximum t a n g e n t i a l f r o s t h e a v e f o r c e e x c e e d i n g 4 kg/cm2 has been recorded.

I n t h e a c t i v e l a y e r o f p e r m a f r o s t r eg ions where t he re is no s t a b l e r e c h a r g e o f g r o u n d w a t e r , t h e g r e a t e s t t a n g e n t i a l f r o s t h e a v i n g f o r c e o f common c l a y u s u a l l y ranges f rom 0 . 3 t o 0 . 4 kg/cm2 i f t h e c l a y is v e r y p l a s t i c . W i t h i n c r e a s i n g w a t e r

162

c o n t e n t (W 100%), t h e t a n g e n t i a l f r o s t h e a v e f o r c e r e a c h e s u p t o 1 . 2 kg/cm2 (Chen Hsiao-pail 1 9 7 2 ; Chang Shang-qin e t al, 1976) .

We m u s t p o i n t o u t t h a t t h e v a l u e s ob ta ined f rom f i e ld measu remen t s a r e a lways lower than those f rom the l abora tory . The main reason i s t h a t i n t h e f o r m e r c a s e , t h e f r e e z i n g r a t e is r e l a t i v e l y low, a l though it is conducive t o mois ture accumula t ion . However, i n f r o z e n s o i l t h e r e l a x a t i o n of stress is s u f f i c i e n t l y d e v e l o p e d . I n t h e l a t t e r c a s e , a l t h o u g h less ice accumula tes b e c a u s e t h e r h e o l o g i c a l process is r a t h e r s h o r t , t h e f r o s t h e a v e p r e s s u r e is o f t e n much g r e a t e r t h a n t h a t o b s e r v e d i n t h e f i e l d . B e c a u s e of laminations and numerous c r a c k s i n t h e n a t u r a l u n d i s t u r b e d s o i l , p a r t o f t h e m o i s t u r e f r e e z e s i n s i d e , a n d w i l l c a u s e t h e f r o s t h e a v e f o r c e t o d iminish .

F r o s t Heave Pressure Normal to Sur face

1. A s p a r t o f t h e t es t d a t a , a c o n c r e t e p i l e h a v i n g a b a s a l s u r f a c e o f 30.6 c m 2 i n f r o z e n loamy c l a y w i t h m o i s t u r e con ten t o f 30 .4% i s s u b j e c t e d t o a recorded f r o s t h e a v e p r e s s u r e n o r m a l t o t h e s u r f a c e r each ing 35.6 kg/cm2 a g a i n s t t h e p i l e b a s e under Laboratory condi t ions. The normal f r o s t h e a v e p r e s s u r e d e c r e a s e s w i t h a n i n c r e a s e i n a r e a of the base (Shen Chong- yen, Wu Tzu-wang, Wang Yan-qing and Chaw Chia-y i , 1 9 7 2 ) .

From f i e l d o b s e r v a t i o n s i n t h e p e r m a f r o s t r e g i o n t h e v a l u e o b t a i n e d f o r u n s a t u r a t e d c l a y e y s o i l g e n e r a l l y was g r e a t e r t h a n t h a t f o r c o a r s e g r a n u l a r soil (Chen Hsiao-pai and Tong Shang-chiang, 1977) . However, i n t h e s a n d g r a v e l l a y e r o f a v a l l e y bot tom where the water t ab le i s sha l low, g r o u n d w a t e r u n d e r p r e s s u r e a f t e r f r e e z i n g a t t h e g r o u n d s u r f a c e f o r c e s m o i s t u r e m i g r a t i o n t o t h e f r e e z i n g p l a n e . F u r t h e r - more, more moisture accumulates a t t h e c o n c r e t e p i l e t h a n i n t h e s u r r o u n d i n g s o i l b e c a u s e o f t h e f o r m e r ' s h i g h e r t h e r m a l c o n d u c t i v i t y a n d c o o l i n g r a t e . T h e r e f o r e , t h e f r o s t h e a v e p r e s s u r e n o r m a l t o t h e s u r f a c e a p p a r e n t l y i n c r e a s e s . If t h e b u r i e d dep th i s 50 c m , t h e f r o s t h e a v e p r e s s u r e normal t o a c o n c r e t e p i l e w i t h a base of 4 0 0 c m 2 w i l l exceed 2 0 kg/cm2. Thus, i n a r eg ion w i th h igh g roundwate r con ten t (o r s u p e r s a t u r a t e d ) , t h e no rma l f ro s t heave p r e s s u r e i s v e r y l a r g e a n d g r e a t c a r e m u s t be t aken .

According t o d a t a c o l l e c t e d by t h e I n s t i t u t e o f S c i e n t i f i c R e s e a r c h on Low Tempera ture Cons t ruc t ion , Hei lungkiang Province , where the g round sur face i s swampy, t h e w a t e r t a b l e b e i n g v e r y s h a l l o w co r re sponds t o t h e w i n t e r f r o s t h e a v e d e p t h . M o r e o v e r , i n h i g h l y p l a s t i c s o i l f o r a c o n c r e t e p i e r w i t h a b e a r i n g s u r f a c e of 2 5 0 0 cm2, a t a dep th of 2 0 cm, a v a l u e

of 1 1 . 6 kg/cm2 f o r f r o s t h e a v e p r e s s u r e normal t o t h e s u r f a c e h a s b e e n r e c o r d e d . When t h e b u r i e d d e p t h is i n c r e a s e d t o 4 0 c m , it is 5.9 kg/crn2.

2 . R e l a t i o n to d e p t h of founda t ion b u r i a l . F i g u r e 7 i l l u s t r a t e s t h e r e l a t i o n between f r o s t h e a v e p r e s s u r e n o r m a l t o t h e s u r f a c e a n d t h e d e p t h o f f o u n d a t i o n b u r i a l (Chen Hsiao-pai and Tong Shang-chiang 1977). I n t h i s f i g u r e , c u x v e I is t h e a c t u a l measured value €or a p i l e o f 2 0 c m x 2 0 cm c r o s s s e c t i o n i n a permafros t reg ion: cu rve I1 shows t h e v a l u e s w i t h d e p t h f o r a foundat ion having 50 cm x 50 c m cross s e c t i o n , r e c o r d e d b y t h e I n s t i t u t e of S c i e n t i f i c R e s e a r c h o n Low Temperature Construct ion, Hei lungkiang Province. Curve I T converges more rap id ly than curve I. Below t h e main f r o s t h e a v e z o n e ( 1 2 0 cm- 1 4 0 c m ) al< 1 kg/cm2, which is a v a l u e t h a t t h e f o u n d a t i o n of a n o r d i n a r y b u i l d i n g could overcome.

3 . R e l a t i o n t o bea r ing area. Every p o i n t i n F igu re 8 i s t h e a c t u a l m e a s u r e d v a l u e o f f r o s t h e a v e p r e s s u r e n o r m a l t o t h e s u r f a c e o f t h e f o u n d a t i o n b a s e a t d i f f e r e n t d e p t h s i n a permafros t reg ion . Curve I i n F i g u r e 7 c a n b e t a k e n a s a b a s e t o t r a n s f o r m t h e m e a s u r e d v a l u e i n t o t h e p r o b a b l e v a l u e a t a d e p t h e q u a l t o ze ro ( i . e . t h e g r o u n d s u r f a c e ) , and c a l c u l a t e t h e g r e a t e s t p r o b a b l e v a l u e (Chen Hsiao-pai and Tong Shang-chiang, 1 9 7 7 ) . A f t e r a n a l y z i n g t h e c u r v e p a t t e r n , w e g e t

u 1 = C + - + - 0 a b F2

i n which ol - f r o s t h e a v e p r e s s u r e n o r m a l 0

t o s u r f a c e a t foundat ion base when bur i ed dep th i s z e r o ( i . e . ground surface) : (kg/cm*) :

F x l o 2 - b e a r i n g a r e a , ( c m 1 . 2

Under c o n d i t i o n s o f t h e c u r v e i n F i g u r e 8 , Formula ( 3 ) becomes:

Oo = 3.85 + - 2 o -+ - 28:-8 (kg/cm ) 2 1 F F

A s F i n c r e a s e s , t h e v a l u e of 0; d e c r e a s e s a s a hype rbo l i c func t ion . When t h e b e a r - i n g a r e a i s v e r y l a r g e , uo -+ 3 .85 kg/cm . 2

1

T e s t o f P r e s s u r e A g a i n s t A S t r u c t u r e

I n o r d e r t o d e t e r m i n e t h e f r o s t h e a v e p res su re on t he back o f a r e t a i n i n g s t r u c t u r e when the g round i s f r o z e n ,

163

Shen Chong-yen, Wu Tzu-wang, Wang Ya-qing and Chang Chia-yi conducted an indoor model test on a s o i l sample 36 x 3 2 x 4 9 c m ( l o n g x wide x h i g h ) , O n l y t h e t o p a n d r e t a i n i n g p l a n e were d i r e c t l y e x p o s e d i n t h e l o w temperature room; t h e r e m a i n i n g f o u r s i d e s were t h e r m a l l y i n s u l a t e d . T h e s u r r o u n d i n g t e m p e r a t u r e g e n e r a l l y w a s m a i n t a i n e d a t -15 +. - 2 O O C ; t h e f r o s t h e a v e p r e s s u r e was measu red w i th a steel w i r e p r e s s u r e t r a n s d u c e r i n t h e t o p , m i d d l e a n d b o t t o m l a y e r s a t t h e b a c k o f t h e r e t a i n i n g s t r u c t u r e . M o i s t u r e c o n t e n t s a t t h e L i q u i d a n d p l a s t i c limits a n d g r a i n s i z e d i s t r i b u t i o n of t h e s a m p l e s are l i s t e d i n T a b l e 2 .

The model tes t shows t h a t t h e f ros t h e a v e p r e s s u r e o n t h e r e t a i n i n g s t r u c t u r e i s c l o s e l y r e l a t e d t o t h e p l a c e w h e r e it is a c t i n g a n d t o t h e s o i l m o i s t u r e c o n t e n t . F i g u r e 9 i l l u s t r a t e s t h a t t h e f r o s t heave p r e s s u r e i n c r e a s e s a s t h e m o i s t u r e c o n t e n t i n c r e a s e s i n d i f f e r e n t t y p e s o f s o i l w i t h v a r i o u s p o s i t i o n s of t h e r e t a i n i n g s t r u c t u r e .

A f i e l d m o d e l t es t o n a r e t a i n i n g w a l l was p e r f o r m e d b y t h e S c i e n t i f i c R e s e a r c h I n s t i t u t e , M i n i s t r y o f R a i l w a y s . T h e h e i g h t of t h e wall was o n e metre, and it was d i v i d e d i n t o f i v e e q u a l s e c t i o n s ( s e p a r a t e d f r o m e a c h o t h e r ) . A p r e s s u r e t r a n s d u c e r w a s used t o m e a s u r e t h e t o t a l force o n e a c h s e c t i o n . I n c o n d i t i o n s of n o d e f o r m a t i o n of t h e wal l , t h e mean f r o s t h e a v e p r e s s u r e a t d i f f e r e n t s e c t i o n s was m e a s u r e d a n d l i s t e d i n T a b l e 3. T h e v a l u e s were found t o be i n a c c o r d a n c e w i t h t h o s e o b s e r v e d a t a n a c t u a l c o n s t r u c t i o n s i t e of t h e same I n s t i t u t e .

Observed Values a t a n A c t u a l C o n s t r u c t i o n S i t e . A s teel wire p r e s s u r e t r a n s d u c e r was u s e d t o measure t h e f r o s t heave p re s su re no rma l t o t h e s u r f a c e a c t i n g a g a i n s t t h e l i n i n g s o f a t u n n e l a n d ve r t i ca l s h a f t w h i l e t h e s u r r o u n d i n g soil was r e f r e e z i n g a n d a l s o t o m e a s u r e t h e h o r i z o n t a l p r e s s u r e a g a i n s t t h e s i d e s o f a b u i l d i n g f o u n d a t i o n when t h e local soil w a s f rozen (Chen Hsa io -pa i l 1972) .

Tunnel and ver t ica l s h a f t . The l a r g e s t v a l u e s of f r o s t h e a v e p r e s s u r e normal t o t h e surface of 4 . 1 and 1 . 4 kg/cm2, were o b t a i n e d r e s p e c t i v e l y f o r t h e c r o w n of t h e a r c h a n d s i d e wal l s of a r a i l w a y t u n n e l i n a r e g i o n of d e e p s e a s o n a l f r o s t . I n t h e p e r m a f r o s t r e g i o n for s a t u r a t e d f r o z e n s a n d y g r a v e l t h e ' g r e a t e s t f r o s t h e a v e p r e s s u r e normal to t h e walls o f a ve r t i ca l s h a f t was found t o b e 1 . 7 kg/cm2 : f o r s a t u r a t e d r e f r o z e n loamy c l a y t h e frost h e a v e p r e s s u r e normal t o t h e wal l s of a ve r t i ca l s h a f t reached 2 .8 kg/cm2.

S i d e s of b u i l d i n g f o u n d a t i o n s . A l t h o u g h t h e o r i e n t a t i o n o f d i f f e r e n t sides

is a c r i t i c a l f ac to r , t h e m o i s t u r e c o n t e n t e x e r t s t h e g r e a t e s t i n f l u e n c e . When t h e g r o u n d s u r f a c e i s m a i n t a i n e d i n a f a i r l y d r y c o n d i t i o n , t h e h o r i z o n t a l f r o s t h e a v e p r e s s u r e n o r m a l t o t h e f o u n d a t i o n s i d e s i s between 0 . 1 t o 0 .3 kg/cm2; when t h e g r o u n d s u r f a c e i s under water o r swampy, t h e f r o s t h e a v e p r e s s u r e r e a c h e d 0- > 1 kg/cm2, and occas iona l ly exceeded 2 kg/cm2.

ADFREEZING STRENGTH BETWEEN SOIL AND FOUNDATION

When t h e p o r e water i n t h e soil l a y e r f r e e z e s , t h e f o r c e t h a t c e m e n t s t h e s o i l p a r t i c l e s a n d f o u n d a t i o n material t o g e t h e r i s t e r m e d t h e a d f r e e z i n g s t r e n g t h b e t w e e n t h e s o i l a n d t h e f o u n d a t i o n ( s i m p l y , a d f r e e z i n g f o r c e ) . I t o c c u r s o n l y when s h e a r d e f o r m a t i o n a p p e a r s b e t w e e n t h e f o u n d a t i o n a n d t h e s o i l . Thus, it is a s o r t of i n d e x f o r s h e a r s t r e n g t h .

L o n g - t e r m c o m p e s s i v e a n d t e n s i l e p i l e tes ts were c o n d u c t e d i n t h e l a b o r a t o r y a n d o u t s i d e w i t h c o n t r o l l e d l o a d i n g , t h e s t a b l e d e f o r m a t i o n s t a n d a r d was found t o b e 0 . 0 1 - 0 . 0 5 m / h r f o r e a c h Load increment.

P r a c t i c a l e x p e r i e n c e i n d i c a t e s t h a t t h e a d f r e e z i n g force i s de te rmined by g r o u n d t e m p e r a t u r e 0 , water c o n t e n t W , t i m e o f a c t i v e l o a d i n g T a n d g r a i n s i z e d , t h a t is:

T h e I n f l u e n c e o f Ground Temperature

A s shown i n F i g u r e 1 0 f o r e a c h so i l t y p e , t h e u n f r o z e n water c o n t e n t W

w i l l decrease w i t h a n i n c r e a s e i n n e g a t i v e t e m p e r a t u r e e a n d t h e c e m e n t i n g ice c o n t e n t w i l l i n c r e a s e , e s p e c i a l l y i n t h e r e g i o n of ab rup t phase change (Xsu Hs ieh - t zu , Tao Chao-xiang and Pu Su-lan, 1 9 7 5 ) . F u r t h e r - more, f o l l o w i n g a c o n t i n u o u s t e m p e r a t u r e d e c r e a s e , t h e s t r e n g t h of ice rises c o r r e s p o n d i n g l y a s i l l u s t r a t e d i n F i g u r e s 11 and 1 2 . When 0 > -5 - -7oC, t h e f o l l o w i n g f o r m u l a c a n b e u s e d (Wu Tzu-wang and Wang Ya-qing, 1972; Chen Hsiao-pai l 1975; Chang Shang-qin, 1976):

unf

T adf 'adf-o + clel '

i n w h i c h : T - A d f r e e z i n g s t r e n g t h when 0 = 0 ( f r e e z i n g

t e m p e r a t u r e ) v a r y i n g w i t h s o i l p r o p e r t y and water c o n t e n t :

0

164

0.01 0.005

0.005 0.001

- "

I 1 < 0 . 0 0 1

1 . 7 2 7.35 6.70

1.11 6 . 1 7 3 . 3 4

T a b l e 2 Water Content a t L i q u i d a n d P l a s t i c L i m i t s and G r a i n S i z e D i s t r i b u t i o n f o r V a r i o u s S o i l S a m p l e s

B a c k f i l l e d S o i l

Clayey Loam

M o i s t u r e C o n t e n t P r e s s u r e (kg/cm )

b e f o r e

2

Freezing . . . . . .

% 0-0.2m 0.2-0.4 0 . 4 - 0 . 6 0.6-0.8 0.8-1.0

1 5 . 7 0.09 0.30 0.39 1.10 1.42 1 T a b l e 3 Actua l Measured Value of L a t e r a l P r e s s u r e o n

a R e t a i n i n g W a l l Model (1977)

C - c o e f f i c i e n t v a r y i n g w i t h so i l p r o p e r t y a n d water c o n t e n t ;

0 - n e g a t i v e t e m p e r a t u r e ;

a - c o e f f i c i e n t less t h a n 1.

I n p r a c t i c e (when 0 > -3 - -4OC1, w e c a n s t a t e a p p r o x i m a t e l y a = 1, t h a t i s :

When t h e t e m p e r a t u r e o f loamy c l a y i s below -7 - -9%, w h e r e t h e ice-water p h a s e h a s r e a c h e d t h e s t a t e o f slow c h a n g e , t h e a d f r e e z e f o r c e w i l l e n l a r g e v e r y l i t t l e w i t h a n i n c r e a s e i n n e g a t i v e t e m p e r a t u r e .

I n f l u e n c e i n M o i s t u r e C o n t e n t

A d f r e e z e s t r e n g t h b e t w e e n t h e s o i l and a f o u n d a t i o n c a n o c c u r only when ice forms

i n t h e pores. , T h e r e f o r e , when t h e m o i s t u r e c o n t e n t i s below t h e u n f r o z e n water c o n t e n t , t h e r e is n o a d f r e e z e force - i . e . t h e soil i s i n t h e s t a t e of b e i n g " d r y f r o z e n " .

F i g u r e 1 3 i l l u s t r a t e s c h a n g e s i n a d f r e e z e s t r e n g t h a t c e r t a i n n e g a t i v e t e m p e r a t u r e s when m o i s t u r e c o n t e n t i n c r e a s e s . (Wu Tzu-wang and Wang Yu-qing, 1 9 7 2 ; Chen Hsiao-pai, 1975; Chang Shang- g i n , 1 9 7 6 ) . When t h e m o i s t u r e c o n t e n t e x c e e d s t h e u n f r o z e n water c o n t e n t , t h e ice c o n t e n t c e m e n t i n t h e so i l p a r t i c l e s a n d f o u n d a t i o n materials a l so i n c r e a s e s . T h e a d f r e e z e force c o r r e s p o n d i n g l y i n c r e a s e s u n t i l a l l t h e v o i d s are s a t u r a t e d w i t h ice. When t h e m o i s t u r e c o n t e n t r e a c h e s Wc t h e soi l p a r t i c l e s

h a v e n o t b e e n , s i g n i f i c a n t l y s e p a r a t e d f r o m e a c h o t h e r a n d t h e a d f r e e z e force r e a c h e s i t s u l t i m a t e v a l u e . W i t h i n t h i s r a n g e , t h e adfreeze force i n c r e a s e s w i t h ice c o n t e n t a n d d i s p l a y s a l i n e a r t r e n d ,

165

t h a t is:

T adf = ' 0 + K (W'Wunf 1 (6)

i n w h i c h : T - f r i c t i o n a l r e s i s t a n c e when 0 w < w unf '

K - c o e f f i c i e n t r e l a t i n g t o n e g a t i v e t e m p e r a t u r e a n d s o i l p r o p e r t y .

When W > W c , t h e i n t e r f a c i n g a c t i o n

between s o i l g r a i n s , ice a n d t h e f o u n d a t i o n material g r a d u a l l y i s d i s p l a c e d b y a n ice- f o u n d a t i o n i n t e r f a c e . A s t h e m o i s t u r e c o n t e n t c o n t i n u e s t o increase, t h e c o r r e s p o n d i n g adfreeze f o r c e s l o w l y a t t e n u a t e s and t e n d s t o become t h e a d f r e e z e s t r e n g t h b e t w e e n t h e ice a n d t h e f o u n d a t i o n material.

E f f e c t of R e l a x a t i o n

I t i s known, t h a t ice unde r l ong- t e rm l o a d h a s a s t r o n g r e l a x a t i o n c h a r a c t e r , which determines t h a t t h e a d f r e e z e s t r e n g t h unques t ionably becomes a f u n c t i o n of l o a d t i m e .

F i g u r e 1 4 shows t h e a d f r e e z e s t r e n g t h b e t w e e n c o n c r e t e a n d f r o z e n s a n d y s o i l a t -4.0 -. - 4 . 2 O C . With a s u r f a c e u n i t l o a d o n t h e test p i l e o f 2 .85 kg/crn2 , f a i l u r e d i d n o t o c c u r u p t o 7 5 h o u r s (Wu Tzu-wang and Wang Yan-qu in , 1972) . Labora to ry e x p e r i m e n t s show t h a t l o n g - t e r m a d f r e e z e s t r e n g t h is a b o u t 1/3 of t h e t r a n s i e n t v a l u e . T h e r e s u l t s o f many f i e l d e x p e r i m e n t s a g r e e w i t h t h e a b o v e r e s u l t ; t h e l o n g - t e r m v a l u e i s a b o u t 0.3-0.4 t h a t of t h e s h o r t - t e r m v a l u e ( r e a c h e s u l t i m a t e v a l u e i n 3-8 minutes) (Chang Qin-sheng and Chang Shang-qin, 1977) .

E f f e c t o f Ice S e g r e g a t i o n

O t h e r factors i n f l u e n c i n g t h e a d f r e e z e force are t h e m e c h a n i c a l a n d m i n e r a l c o m p o s i t i o n of t h e s o i l , soil s a l i n i t y , p r o p e r t i e s of Eoundat ion materials, s u r f a c e r o u g h n e s s , e tc . It is n e c e s s a r y t o i n d i c a t e t h e ice s e g r a t i o n e f f e c t a r o u n d a f o u n d a t i o n s u r f a c e . E x p e r i m e n t s p r o v e t h a t t h e m o i s t u r e c o n t e n t n e a r t h e s o i l above t h e f o u n d a t i o n s u r f a c e is d i f f e r e n t f r o m t h a t s u r r o u n d i n g i t , b e c a u s e t h e f o u n d a t i o n material ( c o n c r e t e , s teel) h a s a h i g h e r t h e r m a l c o n d u c t i v i t y t h a n t h e so i l . There- fo re , when t h e soil a r o u n d t h e f o u n d a t i o n freezes b a c k , h o r i z o n t a l h e a t flow o c c u r s . Moi s tu re accumula t e s and ice s e g r e g a t i o n o c c u r s o n t h e f o u n d a t i o n s u r f a c e w h i c h i s a t t h e f r o s t f r o n t . From f i e l d o b s e r v a t i o n s t h e r e i s a n ice f i l m o f 2-12 mm w h i c h u s u a l l y

I t s t h i c k n e s s v a r y s w i t h m o i s t u r e a n d f r e e z e b a c k c o n d i t i o n s . E x p e r i m e n t s show t h a t when t h e t h i c k n e s s of t h e ice f i l m e x c e e d s 5 mm, t h e a d f r e e z e s t r e n g t h b e t w e e n c l a y e y soi l a n d c o n c r e t e d e c r e a s e s more t h a n 3 0 % over t h a t of i n v i s i b l e ice f i l m s (Chang Qin-sheng and Chang Shang-gin, 1977) . T h e r e f o r e , t h e m e t h o d of c o n s t r u c t i o n , b a c k f i l l material a n d e x t e r n a l f r e e z i n g envi ronment a l l i n f l u e n c e g r e a t l y t h e a d f r e e z e s t r e n g t h s e r i o u s l y .

U s u a l l y , t h e a d f r e e z e s t r e n g t h of u n t r e a t e d metal f o u n d a t i o n s is e x p e c t e d to d r o p 30% more t h a n t h a t of c o n c r e t e , b u t f i e l d d a t a p r o v e t h a t t h i s i s n o t SO (Chang Qin-sheng and Chang Shang-qin, 1977) . Because of t h e g o o d t h e r m a l c o n d u c t i v i t y of metal ( e s p e c i a l l y p i p e p i l e s ) , t h e s o i l a round a f o u n d a t i o n s u r f a c e f r e e z e s q u i c k l y a n d t h e moisture c a n n o t m i g r a t e s u f f i c i e n t l y . T h u s , t h e e f f e c t of ice s e g r e g a t i o n is r e l a t i v e l y weak and i t s a d f r e e z e s t r e n g t h i s s l i g h t l y h i g h e r t h a n t h a t of c o n c r e t e .

MEASUREMENT OF BEARING CAPACITY FOR FROZEN GROUND U S I N G I N S I T U METHOD

Method of Measurement

u p t o now, v a r i o u s c o u n t r i e s u s e d i f f e r e n t ways t o m e a s u r e t h e b e a r i n g c a p a c i t y o f f r o z e n g r o u n d . O u r e x p e r i m e n t shows t h a t t h e so called " i n s i t u " m e t h o d shown i n F i g u r e 1 5 g i v e s t h e best r e s u l t (Wu Tzu-wang, Ma Shi-min and Liu Yang-chi , 1 9 7 7 ) . T h e l o a d i n g p l a t e i s b u r i e d i n t h e f r o z e n s o i l l a y e r a f t e r w h i c h t h e t o p s u r f a c e o f t h e p l a t e a n d t h e c o n n e c t i n g r o d are c o a t e d w i t h g r e a s e . A f t e r t h e m o i s t u r e a n d t e m p e r a t u r e revert t o t h e i r n a t u r a l s t a t e , t h e t es t i s c a r r i e d o u t . The s t a b l e d e f o r m a t i o n s t a n d a r d f o r e a c h l o a d i n c r e m e n t i s < 0.02 mm/hr. This method h a s t h e f o l l o w i n g f a v o u r a b l e f e a t u r e s :

1. I t is similar t o t h e a c t u a l f o u n d a t i o n i n s i t u m e t h o d ;

2 . A s t h e s u r f a c e l a y e r i s almost t h e r m a l l y i n s u l a t e d u n d e r f i e l d c o n d i t i o n s , it r e s u l t s i n t h e g r o u n d t e m p e r a t u r e of t h e b e a r i n g l a y e r b e i n g , r e l a t i v e l y s tab le . I n 4 0 d a y s t h e a m p l i t u d e i s 0.2OC;

3. I t p r o t e c t s t h e s u r f a c e of t h e s o i l samples f rom sub l ima t ion o r o t h e r d i s t u r b a n c e s .

T h e o r e t i c a l l y a n d p r a c t i c a l l y , b o t h p r o v e t h a t t h e p r o p o r t i o n a l l i m i t i n g s t r e n g t h PA o b t a i n e d b y t h e " i n s i t u " method i s almost e q u a l t o t h a t o b t a i n e d w i t h t h e r e g u l a r o p e n m e t h o d of b e a r i n g s u r f a c e tes t . Moreover , it d o e s n o t

forms o n t h e c o n c r e t e f o u n d a t i o n s u r f a c e . - r e l a t e t o t h e area of t h e b e a r i n g p l a t e ,

166

a n d t h e u l t i m a t e s t r e n g t h P j i n t h e " i n i n w h i c h : PAo - p r o p o r t i o n a l l i m i t i n g s i t u " m e t h o d i s o b v i o u s l y h i g h e r t h a n i n l o a d when 0 = f3 t he open me thod . f r e e z i n g t e m p e r a t u r e ;

0

P-S Curve

I n t h e " i n s i t u " s t a t i c load t e s t , i n f r o z e n b o u l d e r y soil, f r o z e n f i n e s a n d , f r o z e n c l a y e y s o i l o r s o i l ice a n d p u r e ice l a y e r s , t h e r e l a t ive c u r v e (P-S) of t h e l o a d s t r e n g t h P and de fo rma t ion S c a n o b v i o u s l y b e d i v i d e d i n t o t h r e e s t a g e s (Wu Tzu-wang, Ma Shi-min and Liu Yung-chi, 1 9 7 7 ) . F i g u r e 1 6 shows t h e P-S c u r v e c h a r a c t e r i s t i c f o r g r o u n d ice c o n t a i n i n g s o i l l a y e r s . F i g u r e 1 r e p r e s e n t s t h e l i n e a r d e f o r m a t i o n s t a g e , i n w h i c h e l a s t i c a n d i r r e v e r s i b l e d e f o r m a t i o n are t h e p r i n c i p a l o n e s . However, t h e t o t a l d e f o r m a t i o n i s n o t g r e a t . T h e so i l ( ice) i s s t e a d i l y c o m p r e s s e d a n d t h e d e f o r m a t i o n e n d s w i t h t h e g r e a t e s t l i n e a r p r o p o r t i o n a l limit of PA.

When t h e l o a d P >, PA, it e n t e r s t h e s e c o n d s t a g e . A t t h i s t i m e , a p l a s t i c z o n e d e v e l o p s a t t h e e d g e of t h e p l a t e a n d c o n t i n u e s t o g row. A l though t he de fo rma t ion u n d e r e a c h l o a d i n c r e m e n t i s g r e a t , it i s still p a r t o f t h e a t t e n u a t i n g s t a g e . I n v i e w o f t h e r h e o l o g i c a l p r o p e r t y of ice, t h i s p r o c e s s i n f r o z e n s o i l c o n t a i n i n g much ice is e s p e c i a l l y o b v i o u s .

A f t e r P > P j , it e n t e r s i n t o t h e t h i r d s t a g e . T h e p l a s t i c z o n e p e n e t r a t e s u n d e r t h e l o a d p l a t e . I f t h e l o a d c o n t i n u e s t o i n c r e a s e , p l a s t i c f l o w o c c u r s i n t h e s o i l a n d t h e d e f o r m a t i o n i s u n a t t e n u a t i n g .

E x p e r i m e n t s s h o w t h a t t h e u l t i m a t e load P j i s abou t 1 .7 -2 .3 times t h e p r o p o r - t i o n a l limit l o a d i n g .

R e l a t i o n of PA t o S o i l T e m p e r a t u r e

L i k e t h e o t h e r s t r e n g t h i n d e x e s of f r o z e n s o i l , s o i l t e m p e r a t u r e i s o n e o f t h e most i m p o r t a n t factors . A n u m b e r o f f i e l d a n d l a b o r a t o r y e x p e r i m e n t s p r o v e t h a t when t h e soil t e m p e r a t u r e is below f r e e z i n g , ice c r y s t a l s o c c u r : t h e c e m e n t i n g b y t h e ice c r y s t a l s c a u s e s t h e b e a r i n g c a p a c i t y o f f r o z e n s o i l t o i n c r e a s e a n d it rises a s t h e n e g a t i v e t e m p e r a t u r e i n c r e a s e s . A s t h e t e m p e r a t u r e i s h i g h e r t h a n -3OC ( t h i s t e m p e r a t u r e r a n g e i s u s u a l l y f o u n d i n p r a c t i c e ) , t h e r e l a t i o n b e t w e e n t h e p r o p o r t i o n a l l i m i t i n g l o a d PA a n d t h e

n e g a t i v e t e m p e r a t u r e is l i n e a r a s shown i n F i g u r e 1 7 (Wu Tzu-wang, Ma Shi-min, Xia Chin- ru and Liu Yang-chi , 1977) . I t c a n b e e x p r e s s e d b y t h e f o l l o w i n g f o r m u l a :

C - c o e f f i c i e n t r e l a t i n g t o s o i l p r o p e r t y a n d moisture c o n t e n t ;

9 - n e g a t i v e t e m p e r a t u r e .

Re la t ion Be tween PA and Mois tu re Con ten t

When t h e m o i s t u r e c o n t e n t e x c e e d s t h e u n f r o z e n water c o n t e n t (and W = f ( e ) ) , unf t h e b e a r i n g c a p a c i t y w i l l i n c r e a s e w i t h m o i s t u r e c o n t e n t as shown i n F i g u r e 18 (Wu Tzu-wang, Ma Shi-min and Lui Yung- c h i , 1 9 7 7 ) . T h e c a u s e i s q u i t e clear when t h e soil p o r e s are almost f i l l e d w i t h ice. T h e b e a r i n g c a p a c i t y r e a c h e s i t s h i g h e s t v a l u e . If t h e m o i s t u r e c o n t e n t i n c r e a s e s , t h e s o i l p a r t i c l e s e n t e r i n t o a suspended s t a t e , a n d t h e p r o p e r t i e s o f t h e f r o z e n so i l a p p r o a c h t h a t of ice. Thus, PA w i l l t end t oward P A i -

R h e o l o g i c a l E f f e c t

Under load ice flows d u e t o a d r o p i n t h e f r e e z i n g p o i n t w h i c h p r o d u c e s p l a s t i c f l o w i m p a r t i n g a r h e o l o g i c a l c h a r a c t e r t o f r o z e n soil .

F i g u r e 1 9 shows t h e r e l a t i o n of s o i l w i t h a n i ce l a y e r of s table p l a s t i c v e l o c i t y v = d s / d t u n d e r t h e c o n d i t i o n o f a c o n s t a n t t e m p e r a t u r e i n t h e l a b o r a t o r y a n d a n e x t e r n a l l o a d P (Wu Tzu-wang, e t a l l 1 9 7 7 ) . F o l l o w i n g a n i n c r e a s e i n e x t e r n a l l o a d , t h e s t a b l e p l a s t i c flow v e l o c i t y i n c r e a s e i n t h e f o r m o f a p a r a b o l i c c u x v e , t h i s is:

V = a p 2 + bp

when e = -1.0 c 0

V = 0.0059p2 + 0 . 0 0 6 ~ ( 8 ' )

F i g u r e 2 0 shows c r e e p l i n e s i n c l a y e y 1 5 . 7 % ) u n d e r l o a d s of 3 , 5 and

~ o ~ ~ / ~ ~ s r e s p e c t i v e l y i n w i t h 8 = 1. O°C (k 0. l 0 C ) and W = 29%. (Wu Tzu-wang e t a l l 1 9 7 7 ) . O b v i o u s l y t h e g r e a t e r t h e l o a d , t h e more t h e d e f o r m a t i o n a n d t h e time r e q u i r e d t o s t a b i l i z e t h e d e f o r m a t i o n w i l l be much l o n g e r . I f it i s e x p r e s s e d i n l o g a r i t h m i c c o o r d i n a t e s as shown i n F i g u r e 2 1 , i t s d e f o r m a t i o n b e f o r e s t a b i l i z - a t i o n c a n b e e x p r e s s e d b y t h e f o l l o w i n g formula : (Wu Tzu-wang e t a1 1 9 7 7 ) .

7.67

l g s = l g so + c l g t (9)

i .e. S = S t C (9' 1 0

i n w h i c h : s -

so -

c -

t -

t o t a l amount of deforma- t i o n :

i n s t a n t a n e o u s d e f o r m a t i o n u n d e r t h e e f f e c t o f l o a d :

c o e f f i c i e n t r e l a t i n g t o l o a d i n g r a t e and s o i l p r o p e r t y ;

l o a d i n g t i m e .

E v i d e n t l y , w i t h d i f f e r e n t l o a d i n g ra tes , t h e time r e q u i r e d t o s t a b i l i z e t h e d e f o r m a t i o n ts i n e v i t a b l y d i f f e r s . F i g u r e 2 2 i l l u s t r a t e s t h e t i m e ts n e e d e d f o r s t a b i l i z i n g d e f o r m a t i o n for t h e s a m p l e s ment ioned above under P = 5 , 8 , 9 . 5 and 11 kg/cm2 r e s p e c t i v e l y (Wu Tzu-wang e t a l l 1 9 7 7 ) . T h u s , w i t h i n t h e r a n g e o f e x p e r i m e n t a l l o a d i n g , it c a n b e e x p r e s s e d b y t h e f o l l o w i n g f o r m u l a :

i n w h i c h : ts - time fo r s t a b i l i z i n g de fo rma t ion unde r P ;

K - c o e f f i c i e n t r e l a t i n g t o s o i l t e m p e r a t u r e a n d m o i s t u r e c o n t e n t .

when p + P d e f o r m a t i o n of t h e s o i l i s e x t r e m e l y small a n d t h e time needed t o s t a b i l i z e it is almost e q u a l t o z e r o .

0'

CHARACTERISTIC INDICES OF THAW CONSOLIDATION OF FROZEN SOIL

I t i s well known t h a t t h e t h a w c o n s o l i d a t i o n o f f r o z e n soil d i f f e r s o b v i o u s l y from t h a t of o r d i n a r y so i l . The v a r i a t i o n i n void r a t i o of f r o z e n g r o u n d are shown i n F i g u r e 23. When t h e p r e s s u r e i s low, t h e f r o z e n s o i l thaws and a f te r - wards under lpad, it c o n s o l i d a t e s a n d t h e v a r i a t i o n i n t h e v o i d r a t i o Ae d u r i n g thawing is:

i n w h i c h : Aeo - v a r i a t i o n i n v o i d r a t i o when f r o z e n soil thaws;

Ae - v a r i a t i o n i n v o i d r a t i o u n d e r l o a d P a f t e r t h e f r o z e n soil thaws.

if allow: A = Ae 0

a = t g P

t h e n A e = A + a p (12)

and amount of s e t t l e m e n t when f r o z e n so i l thaws is:

i n w h i c h : H - t h a w d e p t h o f f r o z e n s o i l l a y e r ;

e , - v o i d r a t i o b e f o r e f r o z e n soil thaws;

l e t : A. = me,- p r a c t i c a l t h a w A

s e t t l e m e n t c o e f f i c i e n t ;

a = - - c1 0

p r a c t i c a l c o m p r e s - " e , s i o n c o e f f i c i e n t .

t h e n : S = H A o + H u P 0 (14)

It s h o u l d be i n d i c a t e d t h a t P i n t h e formula i s t h e a d d i t i o n a l stress o f f r o z e n s o i l a f t e r t h a w i n g , i n c l u d i n g t h e d e a d w e i g h t a n d e x t e r n a l load p r e s s u r e o f t h e soil above (Chen Hsiao-pai and Tong Shang- c h i a n g , 1 9 7 7 ; Chu Yan- l in , 1977).

A. and a0 are t h e c h a r a c t e r i s t i c i n d i c e s i n t h e t h a w c o n s o l i d a t i o n p r o c e s s o f f r o z e n soil. Here w e w i l l g e n e r a l i z e a n d d i s c u s s t h e m b a s e d o n t h e l a r g e a m o u n t o f e x p e r i m e n t a l d a t a f r o m u n d i s t u r b e d soil samples .

T e s t Samples

S o i l s a m p l e s were t a k e n from d e p t h s of 3 . 5 t o 4 m , t h e y i n c l u d e s e a s o n a l l y f r o z e n a n d u n d i s t u r b e d p e r m a f r o s t s o i l samples. The l a t t e r c o n t a i n e d some ice w i t h soil l a y e r s . T h e soil samples were d i v i d e d i n t o : c l e a n s a n d y g r a v e l , g r a v e l c o n t a i n i n g f i n e s , f i n e sand, c l a y e y loam a n d s i l t y c l a y , h e a v y c l a y , etc. The r e p r e s e n t a t i v e g r a i n s i z e a n a l y s i s c u r v e s are shown i n F i g u r e 2 4 (Chu Yan- l in , 1 9 7 7 ) . T h i s w o r k i n c l u d e d b o t h i n s i t u t e s t i n g and sampling .

168

I n t h e t e s t i n g , t h e area of t h e l o a d i n g p l a t e s were 25 x 25 and 50 x 50 c m 2 ; t h e samples had a d i a m e t e r o f 7 . 5 c m and 4 crn i n h e i g h t . One d imens iona l t hawing was m a i n t a i n e d i n t h e t e s t i n g . The s t ab le d e f o r m a t i o n s t a n d a r d c h o s e n i n t h e i n s i t u t e s t i n g , for a l l t y p e s of s o i l , d i d n o t e x c e e d t h e f o l l o w i n g v a l u e w i t h i n 2 h o u r s : c o a r s e - g r a i n s o i l - 0 . 0 2 c m , f i n e - g r a i n soil--O.O5 c m , ice l a y e r c o n t a i n i n g s o i l - 0 . 1 0 c m ; i n t h e small. scale t e s t , t h e r e was f i n e - g r a i n so i l w i t h 0.05 nun, ice l a y e r s a n d 0 .10 mm s o i l l a y e r s r e s p e c t i v e l y (Chu Yan-l in , 1977) .

Prac t ica l Thaw S e t t l e m e n t C o e f f i c i e n t A.

A. is t h e r e l a t ive s e t t l e m e n t c a u s e d by t h e v o l u m e t r i c s h r i n k a g e when ice becomes water which is d r a i n e d o u t d u r i n g t h e thaw of f r o z e n soil. T h e r e f o r e , it relates c l o s e l y w i t h i t s m o i s t u r e c o n t e n t and d r y d e n s i t y ( d e g r e e of s a t u r a t i o n of so i l v o i d s ) .

1. Water c o n t e n t W .

F i g u r e 25 shows t h e r e l a t i o n between A. and W f o r several t y p e s of so i l . On t h e whole , the l i n e s can be d i v i d e d i n t o s t r a i g h t l i n e s e c t i o n s a n d c u r v e s e c t i o n s . I n t h e s t r a i g h t l i n e p o r t i o n , it can be i n d i c a t e d b y :

A. = K(W-Wo)

i n which: K - c o e f f i c i e n t r e l a t i n g t o soil p r o p e r t y ;

Wc - m o i s t u r e c o n t e n t a t t h e boundary of t h e s t r a i g h t l i n e and c u r v e d s e c t i o n ;

Aoc - c o e f f i c i e n t of thaw s e t t l e m e n t when W = Wc

(Chu Yan- l in t 1977)

For the r e l a t i o n s h i p o f A. for ground ice ( ice l a y e r c o n t a i n i n g soil) and W see F i g u r e 2 6 , t h e c u r v e d l i n e A. = 1 0 0 % i s t a k e n as t h e a s y m p t o t e .

2 . D r y d e n s i t y . I n f a c t , t o a c e r t a i n e x t e n t , there e x i s t s a close r e l a t i o n b e t w e e n m o i s t u r e c o n t e n t a n d d r y d e n s i t y . T h u s , t h e r e is also a c o r r e l a t i o n between A. and yd as shown i n F i g u r e 2 7 ;

l e t : y d c - d r y d e n s i t y c o r r e s p o n d i n g t o WC'

when yd b ydc , A- +. yd c u r v e c a n be

e x p r e s s e d by t h e f o l l o w i n g e q u a t i o n (Chu Yan- l in t 1977) :

U (15)

i n w h i c h : K - c o e f f i c i e n t r e l a t i n g t o s o i l p r o p e r t y ;

yd - n a t u r a l d r y d e n s i t y of f r o z e n s o i l ;

ydo - i n i t i a l t h a w s e t t l e m e n t d r y d e n s i t y , i . e . when yd = y d o , An = 0 , -

W - m o i s t u r e c o n t e n t of f r o z e n s o i l ; when yd < ydc, it c a n b e shown approx-

i m a t e l y b y l i n e a r e q u a t i o n (Chu Yan-lin, Wo - m o i s t u r e c o n t e n t when 1 9 7 7 ) :

A. + 0 w i t h c l a y e y so i l wo = 5 + wp w i t h c o a r s e - g r a i n s o i l , Wo = 9-12%. Pract ical C o m p r e s s i o n C o e f f i c i e n t M

(Chen Hsiao-pai l 1972; Wu Tzu-wang, Chang C h i a - y i , Wang Ya-qing and Shen Chong-yen, 1 9 7 2 ; Chang Shang-qin, 1976; Chu Y a n - l i n t 1 9 7 7 ) .

A f t e r t h e f r o z e n soil thaws, u n d e r a n e x t e r n a l l o a d , c o n s o l i d a t i o n i n e v i t a b l y o c c u r s . The p r a c t i c a l c o m p r e s s i o n c o e f f i c i e n t ct0 t h e n becomes t h e c h a r a c t e r -

c a n b e i n d i c a t e d by: thawed s o i l , a0 is d e t e r m i n e d by t h e s t a t e I n the c u r v e d p o r t i o n s e c t i o n , it i s t i c i n d e x of t h a t p r o c e s s . L i k e common

of c o n s o l i d a t i o n of t h e soil which i s t h e Ao' = K' W - W, + Aoc (17) d r y d e n s i t y .

F i g u r e ,28 shows t h a t u n d e r t h e effect of P = 0-2 kg/crn2, c1 var ies w i t h yd ,

af ter thawing of several t y p e s of f r o z e n i n which: K' - c o e f f i c i e n t r e l a t i n g t o 0

soil p r o p e r t y ;

169

so i l . L e t : yd & ydo, x. -+ 0. Thus, when 1 . 4 g/cm3 < yd < ydo, CI almost follows t h e decrease o f yd and shows a l i n e a r i nc rease (Chen Hs iao -pa i l 1972 ; Wu Tzu- wang, Chang Chia-yi, Wang Ya-qing and Shen Chong-yen, 1972; Chu Yan-lin, 1977).

t h a t is: c1 = K (ydo - yd)

0

0 ( 2 0 )

i n w h i c h : K - c o e f f i c i e n t r e l a t i n g t o s o i l p r o p e r t y a n d e x t e r n a l l o a d ;

ydo - d r y d e n s i t y when x. -+ 0 ;

yd - d r y d e n s i t y .

When yd < 1 . 4 g/cm3, t h e c u r v e c h a n g e s s l o w l y a n d becomes i r r e g u l a r . T h e m a i n r e a s o n i s t h a t , a s t h e s o i l i s s u p e r - s a t u r a t e d , t h e p a r t i c l e s are i n a s t a t e o f s u s p e n s i o n . When t h a w e d , u n d e r t h e e f f e c t of t h e l o w stress o f t h e i r d e a d w e i g h t , t h e s u s p e n d e d g r a i n s t e n d t o come i n t o c o n t a c t , s i m u l t a n e o u s l y . I n v i e w of t h e d i f f e r e n t i a t i o n of t h e s t r u c t u r e o f f r o z e n soil, t h e t h a w s e t t l e m e n t s u r e l y h a s a c e r t a i n d i f f e r e n c e a n d a l l of t h e s e n e c e s s a r i l y e x e r t a s t r o n g i n f l u e n c e o n t h e c o m p r e s s i o n c o e f f i c i e n t .

F u r t h e r m o r e , t h e s o d w h i c h g r o w s i n p e r m a f r o s t r e g i o n , p o s s e s s e s g r e a t a b s o r p t i v i t y a n d t h e r m a l i n s u l a t i v e p r o - p e r t i e s . I n d e s i g n a n d c o n s t r u c t i o n , t h e s u b g r a d e s h o u l d be m a i n t a i n e d i n t h e f r o z e n s ta te . T h e s o d m u s t n o t o n l y b e k e p t i n i t s o r i g i n a l c o n d i t i o n , b u t it s h o u l d be c o v e r e d . T h e r e f o r e w e a lso have t o a s c e r t a i n i t s thawed compress ive b e h a v i o u r .

E x p e r i m e n t s s h o w t h a t t h e sod is spongy when thawed. The volumetr ic change of t h e f r o z e n s o i l i s n o t L a r g e , b u t u n d e r l o a d ( e v e n i f smal l ) , it s h o w s v e r y g r e a t c o m p r e s s i v e n e s s . F i g u r e 2 9 , i l l u s t r a t e s t h e r e l a t i o n b e t w e e n t h e c o m p r e s s i v e c o e f f i c i e n t a n d d r y d e n s i t y (Chu Yan-lin, 1 9 7 7 ) .

CONCLUSION AND DISCUSSION

1. F r o s t h e a v i n g a p p e a r s i n s o i l o n l y when t h e m o i s t u r e c o n t e n t e x c e e d s t h e i n i t i a l r e q u i r e m e n t s . T h e m a i n z o n e o f h e a v i n g is i n t h e seasonL.LLy f r o z e n l a y e r . When s a n d a n d g r a v e l are used t o r e p l a c e f r o s t s u s c e p t i b l e s o i l , h e a v i n g c a n o n l y be a c h i e v e d when t h e r e i s a r e l a t i v e l y p e r m e a b l e l a y e r a t t h e b a s e .

2 . The mean t a n g e n t i a l f r o s t h e a v e force i s d i s t r i b u t e d i n t h e ac t ive l a y e r similar t o t h e f r o s t heave zone. Tests

show t h a t t h e water-ice p h a s e o f f r o z e n s o i l is i n a s t a t e of dynamic ba lance .

3 . I n a c l o s e d s y s t e m t h e t a n g e n t i a l frost heave force i n c r e a s e s w i t h water m o i s t u r e c o n t e n t , a n d g r a d u a l l y d e c r e a s e s when it r e a c h e s t h e u l t i m a t e v a l u e .

4 . Frost heave p re s su re no rma l t o a f o u n d a t i o n base decreases w i t h d e p t h i n t h e ac t ive l a y e r . I n t h e r e g i o n of s e a s o n a l l y f r o z e n s o i l , it a t t e n u a t e s r a p i d l y . It still p o s s e s s e s a much l a r g e r v a l u e n e a r t h e p e r m a f r o s t t ab le .

5. The f r o s t h e a v e p r e s s u r e n o r m a l t o t h e s u r f a c e r a p i d l y d e c r e a s e s w i t h a n i n c r e a s e o f b e a r i n g area and can be expres sed by :

o 1 = c + - + - a b F2

6 . A d f r e e z e s t r e n g t h v a r i e s w i t h n e g a t i v e t e m p e r a t u r e , a n d h a s -radf =

-radfo + a 0 I , when 0 > -3 - -40C, it is: c1

T adf = + ' 1

7 . A d f r e e z e s t r e n g t h is r e l a t e d t o m o i s t u r e c o n t e n t a n d b e y o n d t h e u l t i m a t e v a l u e , it g r a d u a l l y t e n d s t o w a r d t h e a d f r e e z e f o r c e o f ice.

8 . S i n c e d i f f e r e n c e s e x i s t i n f o u n d a t i o n mater ia ls , c o n d i t i o n s of b u r i a l a n d s u r r o u n d i n g c o n d i t i o n s , t h e s t a t e of i ce s e g r e g a t i o n a t t h e s i d e of a f o u n d a t i o n d i f f e r s g r e a t l y , d i r e c t l y i n f l u e n c i n g t h e a d f r e e z e s t r e n g t h .

9. T h e d e t e r m i n a t i o n of t h e b e a r i n g c a p a c i t y o f f r o z e n soil u s i n g t h e i n s i t u method i s similar t o t h a t u s i n g t h e b u r i e d method. The soil t e m p e r a t u r e i s s tab le a n d s u b l i m a t i o n a n d o t h e r d i s t u r b a n c e s are prevented . The "P-S" c u r v e t h u s o b t a i n e d c o r r e s p o n d s w i t h t h a t of o r d i n a r y thawed soil .

1 0 . W i t h i n t h e u s u a l t e m p e r a t u r e x a n g e , t h e p r o p o r t i o n a l l i m i t i n g l o a d PA a p p e a r s t o have a l i n e a r r e l a t i o n w i t h n e g a t i v e t e m p e r a t u r e , pA - - pA0 + cl0l. The r e l a t i o n o f PA t o m o i s t u r e c o n t e n t i s

similar t o t h e a d f r e e z e f o r c e .

11. W i t h i n t h e r a n g e of o u r e x p e r i - m e n t s , t h e s t a b l e p l a s t i c y i e l d v e l o c i t y v of ice u n d e r l o a d h a s a r e l a t i o n of V = aP2 -+ bP.

170

1 2 . The r e l a t i o n b e t w e e n f r o z e n s o i l du r ing compress ion before s tab le deforma- t i o n a n d t i m e c a n be i n d i c a t e d b y 1 S =

1 S + C 1 t, a n d t h e s tab le d e f o r m a t i o n

tlme ts h a s a r e l a t i o n of 1

K (1 p-1 P ) w i t h a l o a d P.

g

s o 9 g ts

- -

9 9 0

1 3 . T h e p r a c t i c a l t h a w s e t t l e m e n t c o e f f i c i e n t A. h a s a close r e l a t i o n t o

m o i s t u r e water c o n t e n t . T h e s t r a i g h t s e c t i o n of t h e c u r v e is t h e r a n g e o f t e n u s e d w h i c h c a n b e e x p r e s s e d b y t h e l i n e a r e q u a t i o n A. = K (W-Wo) ; t h e c u r v e d s e c t i o n c a n be i n d i c a t e d b y :

A, = K' + AOC

1 4 . A h a s a close r e l a t i o n t o d r y 0

d e n s i t y y d , when yd & ydo, A. = K (ydo - y d ) / y d ; when y d ydc it c a n be e x p r e s s e d a p p r o x i m a t e l y b y t h e l i n e a r e q u a t i o n A ' =

K (ydo - yd) + Aoc. 0

1 5 . The p r a c t i c a l c o m p r e s s i o n c o e f f i c i e n t u h a s a close r e l a t i o n t o d r y

d e n s i t y , when 1 . 4 g/crn3 < yd < ydo. The l i n e a r e q u a t i o n uo = K(ydo-yd) can be used

t o e x p r e s s it. A f t e r yd < 1 . 4 g/cm3 t h e c u r v e c h a n g e s s l o w l y a n d t h e r e i s no r u l e to which it c a n be r e f e r r e d .

0

1.

2 .

3 .

4.

5.

I

REFERENCES

Wu Tzu-wang, Chang Chia-yi, Wan9 Y a - q ing and Shen Chong-yen. Study of t h e p r o p e r t i e s of F r o s t H e a v i n g of S o i l . 1 9 7 2 . (Unpub l i shed manusc r ip t ) . Chen Bs iao -pa i . Obse rva t ions of F r o s t H e a v e i n t h e S e a s o n a l Active L a y e r , Myl i D i s t r i c t . 1 9 7 2 . (Unpubl i shed m a n u s c r i p t ) .

Shen Chong-yen, Chang Chia-yi, Wang Ya-qing and Wu Tzu-wang. "Research on t h e Lateral F r o s t H e a v i n g F o r c e a g a i n s t t he Founda t ion Dur ing F reez ing" . 1 9 7 2 . ( M a n u s c r i p t ) .

Chen Hs iao-pa i . "The Observa t iona l Study About the Thermal Dynamic Under Subgrade of t h e H e a t i n g B u i l d i n g a n d M e c h a n i c a l S t a b i l i z a t i o n a f F o u n d a t i o n , Myl i Dis t r ic t" . 1 9 7 2 . ( M a n u s c r i p t ) . Shen Chong-yen, Wu Tzu-wang, Wang Yan- qing and Chang Chia-yi. "The Exper imen ta l Resea rch of Normal F r o s t Heav ing Fo rce" . 1972 . (Manusc r ip t ) .

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Shen Chong-yen , Wu Tzu-wang, Wang Yan-qing and Chang Chia-yi. "The P r e l i m i n a r y E x p e r i m e n t a l S t u d y of t h e R e t a i n i n g T h r u s t P r e s s u r e " . 1 9 7 2 . (Manuscr ip t ) . Cheng Kuo-tung, Chen Hsiao-pail Kuo Tong-hsin and Tong Pe- l iang. "Cryopedo logy" . P re s s of S c i e n c e . 1975 .

Wu Tzu-wang and Wang Yan-qing. "The S t u d y of A d f r e e z i n g S t r e n g t h Between t h e F o u n d a t i o n a n d F r o z e n S o i l " . 1 9 7 2 . ( M a n u s c r i p t ) .

Chang Shang-qin, e t a l . P r e l i m i n a r y S tudy of Some P r o p e r t i e s o f Frozen S o i l M e c h a n i c s a l o n g t h e C h i n g h a i - T i b e t Highway. Reports of Lanchow I n s t i t u t e of Glac io logy Cryopedo logy and Desert Resea rch , Academia S in i ca N o . 1. 1 9 7 6 . P r e s s of S c i e n c e .

C h e n H s i a o - p a i . C h a r a c t e r i s t i c s o f Thaw C o n s o l i d a t i o n of P e r m a f r o s t , Myl i District. 1972. (Unpublished m a n u s c r i p t ) . Wu Tzu-wang, Chang Chia-yi, Wang Ya-qing and Shen Chong-yen. Prelim- i n a r y S t u d y o f Thaw C o n s o l i d a t i o n of Frozen S o i l . 1 9 7 2 . (Unpubl i shed M a n u s c r i p t ) . Chen Hsiao-pail Tong Shang-chiang. Tes t ing and Resea rch of F r o s t Heave Pres su re . 1977 . (Unpub l i shed m a n u s c r i p t ) . Chang Qin-sheng, Chang Shang-qin. S t u d y o f A d f r e e z e S t r e n g t h B e t w e e n F r o z e n S o i l a n d a F o u n d a t i o n S u r f a c e . 1 9 7 7 . (Unpub l i shed manusc r ip t ) . Wu Tzu-wang, Ma Shi-nin, Liu Yung-Chi . D e t e r m i n a t i o n of t h e B e a r i n g C a p a c i t y of F r o z e n G r o u n d w i t h t h e I n S i t u i n Method. 1977. (Unpublished m a n u s c r i p t ) . Chu Y a n - l i n . C h a r a c t e r i s t i c s of Thaw Set t lement and Compress ion o f Frozen Ground. 1977. (Unpublished m a n u s c r i p t ) .

F i g u r e C a p t i o n s

F i g u r e 1. The d i s t r i b u t i o n o f frost heave r a t e t h r o u g h t h e act ive l a y e r .

F i g u r e 2 . Schemat i c d i ag ram of d i f f e r e n t f r o s t h e a v e f o r c e s .

F i g u r e 3 . L i n e s of d e v e l o p i n g t a n g e n t i a l f r o s t h e a v e f o r c e w i t h time.

171

F i g u r e 4 .

F i g u r e 5.

F i g u r e 6 .

F i g u r e 7 .

F i g u r e 8 .

F i g u r e 9 .

F i g u r e 1 0 .

F i g u r e 11.

F i g u r e 1 2 .

F i g u r e 13.

F i g u r e 14.

F i g u r e 1 5 .

F i g u r e 1 6 .

F i g u r e 1 7 .

F i g u r e 1 8 .

F i g u r e 1 9 .

F i g u r e 20.

F i g u r e 2 1 .

F i g u r e 22.

S t a t e of f r o s t h e a v e force p a r t i a l l y r e c o v e r e d a f t e r u n l o a d i n g .

V a r i a t i o n of mean t a n g e n t i a l f r o s t h e a v e force t h r o u g h t h e f r o z e n d e p t h .

R e l a t i o n s h i p b e t w e e n t a n g e n t i a l f r o s t h e a v e f o r c e a n d water c o n t e n t i n a c l o s e d s y s t e m .

V a r i a t i o n w i t h d e p t h of f r o s t heave p re s su re no rma l t o s u r f a c e .

V a r i a t i o n s o f f r o s t h e a v e p r e s s u r e n o r m a l t o s u r f a c e w i t h t h e b e a r i n g area.

R e l a t i o n of f r o s t h e a v e p r e s s u r e t o m o i s t u r e c o n t e n t i n a soil model t es t .

Unfrozen water c o n t e n t i n r e l a t i o n t o c h a n g e i n n e g a t i v e t e m p e r a t u r e .

T r a n s i e n t a d f r e e z i n g s t r e n g t h o f s a n d y soil i n r e l a t i o n t o n e g a t i v e t e m p e r a t u r e .

A d f r e e z i n g s t r e n g t h o f loamy c l a y i n r e l a t i o n t o n e g a t i v e t e m p e r a t u r e .

A d f r e e z e s t r e n g t h i n r e l a t i o n t o m o i s t u r e c o n t e n t .

A d f r e e z e s t r e n g t h b e t w e e n f r o z e n s a n d y s o i l a n d c o n c r e t e .

S k e t c h of l o a d i n g tes t u s i n g i n s i t u m e t h o d .

P-S c u r v e of ground ice c o n t a i n i n g s o i l .

R e l a t i o n s o f p r o p o r t i o n a l l i m i t i n g l o a d PA t o s o i l t e m p e r a t u r e .

The r e l a t i o n of PA and W i n loamy clay.

R e l a t i o n b e t w e e n p l a s t i c f l o w v e l o c i t y of i ce L a y e r c o n t a i n - i n g so i l a n d e x t e r n a l load.

C r e e p l i n e s i n loamy c lay .

D e f o r m a t i o n l i n e s i n l o a m y c l a y b e f o r e s t a b i l i z a t i o n .

R e l a t i o n s b e t w e e n t h e s t a b i l i z i n g time t of deformation and load p.

S

F i g u r e 2 3 .

F i g u r e 2 4 .

F i g u r e 25.

F i g u r e 26 .

F i g u r e 27 .

F i g u r e 2 8 .

F i g u r e 2 9 .

V a r i a t i o n s i n void r a t i o d u r i n g t h a w c o n s o l i d a t i o n of f r o z e n so i L . Main g r a i n s i z e d i s t r i b u t i o n of t es t soils.

C u r v e s r e l a t i n g A and W f o r

several t y p e s of f r o z e n so i l .

C u r v e r e l a t i n g A. and W f o r ice l a y e r c o n t a i n i n g soil.

Curves for r e l a t i o n b e t w e e n A

and yd f o r s e v e r a l t y p e s o f f r o z e n so i l .

C u r v e s r e l a t i n g u0 and yd

a f t e r t h a w i n g f o r s e v e r a l t y p e s o f f r o z e n s o i l .

Re la t ion be tween a0 and yd for sod *

0

0

F i g u r e 1

172

t

4 4

F i g u r e 2

Figure 3

Relative mean tangential froett heaving forceg

-.- 4 f I.'

F i g u r e 5

F i g u r e 6

F i g u r e 7

173

I ! :

Figure 8

Figure 10

O 1 -f -/0 -tf 0:

Figure 1 2

174

I

Figure 13

5 P I5 . t c l i ,

Figure 14

T i lye'

Figure 15

J,I Figure 16

0

I

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P 7

P "b

F i g u r e 18

Figure 19

Figure 2 0

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F i g u r e 21

F i g u r e 2 2

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F i g u r e 2 4

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TESTING OF PILE FOUNDATIONS I N PERMAFROST AREAS

R e s e a r c h G r o u p o n P i l e F o u n d a t i o n s i n P e r m a f r o s t , R e s e a r c h I n s t i t u t e of M i n i s t r y of Ra i lways , The Peop le ' s Repub l i c of China.

ABSTRACT

T h i s r e p o r t p r e s e n t s t h e n a t u r a l g e o g r a p h i c a l a n d g e o l o g i c a l c o n d i t i o n s of t w o p e r m a f r o s t p i l e tes t s i tes , o n e l o c a t e d i n t h e K u k u s i l i M o u n t a i n s a n d t h e o t h e r n e a r t h e Chumar R i v e r o n t h e C h i n g h a i - T i b e t P l a t e a u . T h e f r e e z e b a c k of t h e p i l e , t h e h a r d e n i n g of c o n c r e t e a t l o w t e m p e r a t u r e , d u r a b i l i t y a n d r e s i s t a n c e t o f r e e z i n g a n d thawing of t h e c a s t - i n - p l a c e r e i n f o r c e d c o n c r e t e p i l e f o u n d a t i o n s , a n d r e s u l t s of s ta t ic l o a d tests a re a l so d e s c r i b e d .

I n c o m p a r i s o n w i t h o t h e r t y p e s o f f o u n d a t i o n s i n p e r m a f r o s t areas , p i l e s have some a d v a n t a g e s . P i l e f o u n d a t i o n s h a v e t h e r e f o r e b e e n a d o p t e d r e c e n t l y i n b r i d g e a n d b u i l d i n g c o n s t r u c t i o n i n p e r m a - f r o s t areas of China . The main types used h e r e a re d r i l l e d d r i v e n p i l e s , d r i l l e d p l a c e m e n t p i l e s a n d d r i l l e d c a s t - i n - p l a c e p i l e s . A l l of them are of r e i n f o r c e d c o n c r e t e . I n o r d e r t o d e v e l o p d e s i g n a n d c o n s t r u c t i o n c r i t e r i a for t h e a b o v e - m e n t i o n e d f o u n d a t i o n s , i n a d d i t i o n t o s u p p o r t i n g l a b o r a t o r y e x p e r i m e n t s , t w o p i l e tes t si tes, o n e i n t h e K u k u s i l i Mountains (Test S i t e K ) a n d t h e o t h e r a t t h e Chumar River (Test S i t e C H ) , were e s t a b l i s h e d €or r e s e a r c h p u r p o s e s .

T e s t S i t e s K and CH are b o t h l o c a t e d i n c o n t i n u o u s p e r m a f r o s t o n t h e C h i n g h a i - T i b e t P l a t e a u a t a l t i t u d e s of 4618 m and 4470 m w i t h mean a n n u a l a i r t e m p e r a t u r e s o f -5.7OC and -6.2OC r e s p e c t i v e l y . T h e g r o u n d t e m p e r a t u r e a t t h e d e p t h of z e r o a m p l i t u d e i n b o t h s i tes is -1.5OC a t a d e p t h of 1 0 rn and -l .O°C a t a d e p t h of 8 m. The t h i c k n e s s of t h e s e a s o n a l l y t h a w e d l a y e r i s 1 . 5 - 2 . 0 m and 2 . 0 - 2 . 5 m. The former s i t e h a s d e n s e so i l wi th l ow ice c o n t e n t a n d w e l l d e v e l o p e d s u p r a p e r m a f r o s t water, w h i l e t h e l a t t e r h a s s t r a t i f i e d s o i l w i t h v o l u m e t r i c ice c o n t e n t of 4 0 % t o 70%.

The geo log ica l co lumns and c u r v e s of g r o u n d t e m p e r a t u r e are shown i n F i g u r e 1.

T h e p l a n a n d t e c h n i c a l a s p e c t s of t h e t es t p i l e s a t t h e t w o s i tes are shown i n F i g u r e 2 and Table 1.

The main t es t r e s u l t s are as follows:

FREEZEBACK

T h e t h e r m a l e q u i l i b r i u m of t h e perma- f r o s t a r o u n d t h e p i l e s was d i s t u r b e d d u e t o i n s t a l l a t i o n , a n d t h e g r o u n d n e a r t h e p i l e s may even be thawed. A f t e r a p e r i o d o f some hea t exchange , t he t hawed g round becomes re f rozen so t h a t a new s t a t e of t h e r m a l e q u i l i b r i u m i s e s t a b l i s h e d . T h e time t a k e n f o r f r e e z e b a c k d e p e n d s o n t h e amount of h e a t . ( h e a t d u e t o d r i l l i n g , h e a t from t h e d r i l l i n g s l u r r y , b a c k f i l l mater ia l a n d c o n c r e t e m i x t u r e , a n d h e a t of cemen t hydra t ion ) and t he g round t h e r m a l r e g i m e a r o u n d t h e p i l e s .

A s o b s e r v e d a t t h e t w o t es t s i tes , t h e time of f r e e z e b a c k f o r d r i l l e d d r i v e n p i l e s a n d d r i l l e d p l a c e m e n t p i l e s i s q u i t e s h o r t , a n d it is e v e n n o t v e r y l o n g f o r c a s t - i n - p l a c e p i l e s .

D r i l l e d D r i v e n P i l e s

Because on ly a small amount of h e a t w a s i n t r o d u c e d d u e t o c o n s t r u c t i o n , t h e r i se i n g r o u n d t e m p e r a t u r e a r o u n d t h e d r i l l e d d r i v e n p i l e s w a s r a t h e r small. F r e e z e b a c k w a s c o m p l e t e d m a i n l y i n 7 t o 11 d a y s a f t e r p l a c e m e n t ( F i g u r e 3 ) . T h i s d e m o n s t r a t e s t h a t n a t u r a l f r e e z e b a c k may be u s e d f o r d r i l l e d d r i v e n p i l e s i n t h e s e tes t areas.

D r i l l e d P l a c e m e n t P i l e s

Because a c o m p a r a t i v e l y l a r g e a m o u n t of h e a t w a s i n t r o d u c e d i n t h e b a c k f i l l m a t e r i a l a r o u n d t h e p i l e s , t h e time of f r e e z e b a c k r e q u i r e d w a s 3 t o 4 d a y s l o n g e r t h a n t h a t f o r t h e d r i l l e d d r i v e n p i l e s , i . e . L O t o 1 5 d a y s w e r e needed f o r t h e c o m p l e t i o n of f r e e z e b a c k a f t e r p l a c e - men t (F igu re 4 ) . T h i s m e a n s t h a t n a t u r a l f r e e z e b a c k c a n a lso be u s e d i n d s i l l e d p l a c e m e n t p i l e c o n s t r u c t i o n f o r t h e tes t sites.

180

Bored

S i t e

T u b u l a r Rc 1 4 0 0 1 350

K

RC 1 Tubular I 300 I 350 +

CH 1 1

1 RC 1 550 1 T u b u l a r 650

Method of P i l e

P l a c e - men t

D r i l l e d d r i v e n

D r i l l e d p lacement

D r i l l e d d r i v e n

D r i l l e d p lacement

D r i l l e d c a s t - i n

p l a c e

P l a c e -

( p c s )

7 . 5 l 3 I

8.0 I 3

T a b l e 1 T e c h n i c a l C h a r a c t e r i s t i c s of Test P i l e s

D r i l l e d C a s t - i n - p l a c e P i l e s

F o r c a s t - i n - p l a c e p i l e s , d u e t o t h e r a t h e r h i g h t e m p e r a t u r e (lO°C - 2OoC) of t h e c o n c r e t e m i x a n d i n a d d i t i o n , t h e c e m e n t h y d r a t i o n h e a t i n v o l v e d , t h e r e w a s a s u b s t a n t i a l rise o f t empera tu re a round t h e p i l e s . Hence t h e f r e e z e b a c k l a s t e d a p p r o x i m a t e l y 30 d a y s ( F i g u r e 5 ) . A l o w t e m p e r a t u r e ( a r o u n d O°C) m o i s t u r e w i l l g r e a t l y r e d u c e t h e v o l u m e t r i c h e a t c o n t e n t of t h e c o n c r e t e a n d w i l l a l s o d e l a y t h e h y d r a t i o n a c t i o n of the cemen t . Thus , some r e d u c t i o n i n t h e r m a l d i s t u r b a n c e t o t h e f r o z e n s o i l a r o u n d t h e p i l e w i l l o c c u r w h i c h l e a d s t o a s h o r t e n i n g of t h e f r e e z e - back t i m e .

Dr i l led C a s t - i n - p l a c e C o n c r e t e P i l e s

Dril led c a s t - i n - p l a c e p i l e s h a v e t h e a d v a n t a g e s o f a l a r g e d i a m e t e r a n d h i g h b e a r i n g c a p a c i t y . T h e y are a l so s u i t a b l e f o r v a r i o u s l i t h o l o g i c a l c o n d i t i o n s a n d f o r areas o f a c t i v e g r o u n d w a t e r . T h e r e - fo re , t h e y a re a s u p e r i o r t y p e of f o u n d a t i o n f o x s t r u c t u r e s c a r r y i n g h e a v y l o a d s . However, e f f o r t s m u s t b e made t o m i n i m i z e t h e t h e r m a l effect o f t h e c o n c r e t e , t o accelerate i t s h a r d e n i n g a t l o w temper- a t u r e s a n d t o improve i t s d u r a b i l i t y a n d r e s i s t a n c e t o f r e e z i n g a n d t h a w i n g . F o r t h e s e p u r p o s e s a series of t e s t s was carried o u t b o t h i n t . he l abo ra to ry and a t t h e s i t e f o r w h i c h g o o d r e s u l t s were a c h i e v e d .

E f f o r t s were made t o m o d i f y a n d i m p r o v e t h e t e c h n i c a l p r o p e r t i e s o f t h e c o n c r e t e u s e d fo r d r i l l e d c a s t - i n - p l a c e p i l e s , m a i n l y t h r o u g h t h e u s e of c h e m i c a l a d d i t i v e s

T h r e e d i f f e r e n t p r e p a r a t i o n s of a d d i t i v e s were u s e d i n t h e tes ts :

(1) A i r - e n t r a i n i n g a g e n t (AEA - a l k y l s u l f o n a t e ) + a c c e l e r a t i n g a g e n t (AA - s o d i u m c h l o r i d e a n d s u l p h a t e ) ;

n a p h t h o l s u l f o n a t e or n a p h t h o l s u l f o n i c ac id - fo rma ldehyde dehydra t ion p roduc t ) + AA;

a g e n t (FR?, - n i t r a t e ) .

( 2 ) Wate r - r educ ing agen t (WRA -

( 3 ) WRA + AA + f r e e z i n g r e s i s t a n c e

The t es t materials were o r d i n a r y c e m e n t a n d e a r l y - s t r e n g t h c e m e n t , r i v e r s and , c rushed s tone and pebb les . The water-cement r a t i o w a s 0 .30 - 0.60. The t es t specimen w e r e c u r e d a t t e m p e r a t u r e s of 2OoC, O°C, -3OC, -5OC and -lO°C d u r i n g h a r d e n i n g . Various tests for d e t e r m i n i n g t h e p h y s i c a l m e c h a n i c a l p r o p e r t i e s a n d r e s i s t a n c e t o f r e e z i n g a n d t h a w i n g were u n d e r t a k e n . F i e l d tes ts i n c l u d e d embed- d i n g t h e r m o c o u p l e s a n d t h e r m i s t o r s i n t h e p i l e t o tes t t h e t h e r m a l e f f e c t o f t h e c o n c r e t e . R e s u l t s p r o v e d t h a t t h e specimen made of low w a t e r - c e m e n t r a t i o c o n c r e t e a n d b l e n d e d w i t h c h e m i c a l a d d i t i v e s showed e x c e l l e n t w o r k a b i l i t y . Compared t o spec imens w i thou t addi t ives , t h e r a t e of h a r d e n i n g u n d e r l o w ( o r n e g a t i v e ) t e m p e r a t u r e a n d the c a p a b i l i t y

181

o f r e s i s t i n g f r e e z i n g a n d t h a w i n g showed a p p r e c i a b l e i n c r e a s e s . The s t r e n g t h v a l u e s ob ta ined from specimens cured i n c ryogen ic c o n t a i n e r s (cold chambers) coincided approx ima te ly w i th t hose ob ta ined i n ou t - d o o r s t e s t p i t s i n t h e f r o z e n g r o u n d . A l l t h e v a l u e s o b t a i n e d were up t o or above t h e d e s i g n e d v a l u e . T h e v a l u e s € o r c o u n t e r - measures f reez ing and thawing were a l s o u p t o o r o v e r "200 and m e t t h e d e s i g n e d d u r a b i l i t y c r i te r ia . D u r i n g t h e f i r s t f e w d a y s u p t o a d o z e n o r m o r e a f t e r p l a c i n g of t h e c o n c r e t e , t h e t e m p e r a t u r e s i n s i d e t h e c o n c r e t e p i l e s were above zero and then l o w e r e d g r a d u a l l y u n t i l a s t a t e of e q u i l - i b r i u m i n r e l a t i o n t o t h e t e m p e r a t u r e of t h e f r o z e n g r o u n d was a t t a i n e d . G e n e r a l l y t h i s t u r n e d o u t t o b e d u r i n g a 2-3 week per iod. Keeping down t h e i n i t i a l temp- a t u r e of t h e c o n c r e t e mix was f a v o u r a b l e to p romot ing thermal equi l ibr ium be tween t h e p i l e s a n d t h e s u r r o u n d i n g f r o z e n g r o u n d a n d t h e r e f r e e z i n g p e r i o d o f t h e l a t t e r was reduced. So, when c a s t i n g t h e p i l e s a t empera tu re o f app rox ima te ly OOC shou ld be ma in ta ined i n t he conc re t e mix .

The key t o s u c c e s s f u l r e s u l t s w i t h c a s t - i n - p l a c e p i l e s l i e s i n t h e c o n c r e t e m a t e r i a l s u s e d a n d t h e p r o c e d u r e f o l l o w e d i n t h e i r i n s t a l l a t i o n . Adding chemical a d m i x t u r e s i n t o t h e c o n c r e t e mix 3s a promising method.

S t a t i c L o a d i n g Tests

V e r t i c a l a n d l a t e r a l s t a t i c l o a d i n g tes ts were b o t h c a r r i e d o u t a t Test S i t e s K and CH (F igu re 6 ) . Tes t ing i n s t rumen t s I

and loading equipment a re shown i n F i g u r e 7 . I n t e r n a l f o r c e s a t d i f f e r e n t s e c t i o n s a n d r e a c t i o n f o r c e s a t t h e l o w e r end o f each p i l e were measured by resis- t a n c e s t r a i n g a u g e s and p r e s s u r e s e n s o r s . Set t lement and displacement were measured by micrometers.

Loading proceeded in several s t a g e s . For t h e v e r t i c a l l o a d i n g t es t , t h e l o a d a p p l i e d a t t h e f i r s t s t a g e a c c o u n t e d f o r 50% of t h e d e s i g n v a l u e . I n s u b s e q u e n t s t a g e s t h e l o a d was a p p l i e d i n i n c r e m e n t s of LO% of t he des ign l oad . Each l oad increment was appl ied when t h e p r e v i o u s loading reached a s ta te o f s t a b i l i t y . The c r i t e r i o n o f s t a b i l i t y is: p i l e s e t t l e m e n t less than 0 .5 mm i n 2 4 hours and obse rved fo r 3 consecu t ive days. S h o u l d t h e l o a d i n g a t a n y s t a g e n o t r e a c h s t a b i l i t y w i t h i n 1 0 d a y s , t h e tes t should b e s t o p p e d . F o r t h e l a t e r a l l o a d i n g t e s t , l o a d s were a p p l i e d i n e q u a l i n c r e m e n t s . A disp lacement of less t han 0 . 0 2 mm p e r h o u r w a s t a k e n a s t h e c r i t e r i o n o f s t a b i l i t y . I n c a s e s t a b i l i t y c a n n o t b e achieved dur ing a c e r t a i n l o a d i n g s t a g e which is s u s t a i n e d for 24 h o u r s t h e tes t should be s topped .

The fol lowing points have emerged t h r o u g h t h e t e s t i n g :

1. Under a v e r t i c a l l o a d i n t h e permafros t a p i l e f o u n d a t i o n w i l l form an e q u i l i b r i u m f o r c e s y s t e m c o n s i s t i n g o f t h e f r i c t i o n of t h e t h a w e d s o i l , a d f r e e z - i ng bond of t h e p e r m a f r o s t , r e a c t i o n f o r c e a t the lower end of t h e p i l e s and t h e e x t e r n a l l o a d . The magnitude and composi- t i o n o f t h e f i r s t t h r e e v a r y w i t h t h e e x t e r n a l l o a d a n d t h e r a t e of load ing . When t h e l o a d i s small, t h e r e w i l l be no r e a c t i o n f o r c e a t t h e Lower end of the p i l e . I t a p p e a r s a p p a r e n t l y o n l y when s e t t l e m e n t occurs a t a c e r t a i n l o a d c a u s i n g r e l a x a t i o n o f t h e a d f s e e z i n g f o r c e i n t h e u p p e r p a r t down t o a c e r t a i n d e p t h . I f t h e l o a d i n g time i s pro longed and the l o a d i n c r e a s e d , t h e r e l a x a t i o n phenomenon w i l l develop cont inuously. Correspond- e n t l y , t h e r e a c t i o n f o r c e a t t h e l o w e r e n d w i l l g r a d u a l l y i n c r e a s e a t t h e same t i m e , and r each up t o 9 % o f t h e t o t a l r e a c t i o n

R e a c t i o n F o r c e a t V e r t i c a l Load Lower End

Pe rcen tage Load S u s t a i n e d S e t t l e m e n t o f u l t i m a t e

Appl ied Appl ica t ion o f Pile-Top Magnitude Loading (t) ( 2 4 h r s ) (m) ( t ) Capaci ty

15 1 0 . 0 9 0 .036 0 . 2 4

30 1 0 . 4 6 1.450 4.83

I 45* I 9 I 15.08 [ 4.168 I 9 . 2 6 I * Ul t ima te l oad

Table 2 Relat ionship between React ion Force a t Lower End of Dr i l l ed P l acemen t P i l e a n d V e r t i c a l Load a t T e s t S i t e K

182

Dri l led

P i l e p l a c e

Tempera ture of I Frozen Ground

F r e e z i n g I I D r i l l e d

I

-1.0 6.0 8.7 "-

-0 .5 4 . 1 8 . 2 12.2

T a b l e 3 Ultimate a d f r e e z i n g s t r e n g t h a r o u n d p i l e s

f o r c e w i t h u l t i m a t e l o a d i n g ( F i g u r e 2 ) . The r e s u l t s m e n t i o n e d a b o v e i n d i c a t e t h a t t h e r e e x i s t s a problem of t h e optimum l e n g t h of t h e p i l e s f o x e c o n o m i c p u r p o s e s i n d e s i g n i n g p i l e f o u n d a t i o n . F u r t h e r s t u d i e s a re r e q u i r e d t o d e t e r m i n e t h e l e n g t h .

2 . T h e a d f r e e z i n g f o r c e var ies g r e a t l y w i t h t h e t y p e o f p i l e f o u n d a t i o n a n d c o n - s t r u c t i o n m e t h o d . T h e a d f r e e z i n g f o r c e of a d r i l l e d p l a c e m e n t p i l e is a t a maximum w h i l e t h a t of t h e d r i l l e d d r i v e n p i l e i s a t a minimum ( F i g u r e 3 ) . B u t b o r e d p l a c e - m e n t p i l e i s c o n v e n i e n t fo r c o n s t r u c t i o n . I t s b e a r i n g c a p a c i t y c a n also b e g r e a t l y i n c r e a s e d when a p p l y i n g s p e c i a l s u r f a c e f e a t u r e .

3. I n m a k i n g c a l c u l a t i o n s f o r a p i l e f o u n d a t i o n u n d e r h o r i z o n t a l l o a d , t h e f o l l o w i n g e q u a t i o n c a n b e a p p l i e d t o c h o o s e t h e f o u n d a t i o n m o d u l u s a l o n g t h e p i l e l e n g t h s u i t a b l e for p e r m a f r o s t .

K = m Z n

where K - founda t ion modu lus m - c o e f f i c i e n t of f o u n d a t i o n

m o d u l u s v a r y i n g w i t h t h e d e p t h

g r o u n d s u r f a c e

l o g i c a l c h a r a c t e r

2 - l e n g t h of p i l e b e n e a t h

n - power v a r i e s w i t h l i t h o -

The bending moment of t h e p i l e c a n b e t e s t e d a n d c o m p a r e d w i t h t h e a c t u a l measured moment . The d i s t r ibu t ion of f o u r f o u n d a t i o n m o d u l i a l o n g t h e d e p t h i n F i g u r e 8 c a n bc used fo r c a l c u l a t i o n . R e s u l t s show t h a t t h e maximum bending moment and maximum b e n d i n g p o s i t i o n c a l c u l a t e d by means of (d) are n e a r t h e a c t u a l m e a s u r e d v a l u e ( F i g u r e 9 ) .

4 . I n p e r m a f r o s t areas, t h e f o u n d a - t i o n s o i l a r o u n d t h e p i l e s c o n s i s t s of thawed s o i l n e a r t h e t o p , p l a s t i c h i g h c r e e p f r o z e n s o i l i n t h e m i d d l e a n d low c r e e p f r o z e n soil a t t h e bottom. The

r e a c t i o n force c o e f f i c i e n t a t t h e t o p i s v e r y small, b i g g e r a t the bo t tom, and i n t e r m e d i a t e i n t h e m i d d l e . T h e d i s t r i - b u t i o n o f t h e f o u n d a t i o n m o d u l u s i s a c o n c a v e p a r a b o l a a b o v e t h e f i r s t e las t ic zero p o i n t . I t i s n e a r t h e a c t u a l c o n - d i t i o n . The f i r s t e l a s t i c z e r o p o i n t i s l o c a t e d below t h e f r e e z e - t h a w i n t e r f a c e of t h e s o i l . T h e d i s t a n c e b e t w e e n t h e f i r s t e las t ic zero p o i n t a n d t h e f r e e z e - t h a w i n t e r f a c e i s r e l a t e d t o t h e p i l e d i a m e t e r a n d t h e c h a r a c t e r i s t i c s of t h e p e r m a f r o s t .

5. I t is u n r e a l i s t i c t o u s e o n l y t h e f i x e d d i s p l a c e m e n t t o work o u t t h e parameter m of t h e above f o r m u l a . Two u l t i m a t e c o n d i t i o n s s h o u l d b e c o n s i d e r e d , s u c h a s t h e s p l i t t i n g of t h e p i l e a n d t h e r e s t r a i n t e f f e c t of t h e f o u n d a t i o n o n t h e p i l e s , a n d t h e smaller v a l u e t a k e n . T h e v a l u e m o b t a i n e d b y t h i s m e t h o d a n d t h e f o u n d a t i o n modulus K of t h e t e s t p i l e o b t a i n e d f r o m (d) i n F i g u r e 8 a re a s f o l l o w s :

(1) When mean ground temperatur tl = -0.5OC, K1 = 130 kg/cm 7

(2) When mean g r o u n d t e m p e r a t u r e t2 t2 = -l.O°C, K 2 = 2 0 0 kg/cm3

I n p r a c t i c e , K s h o u l d be d e d u c t e d a c c o r d i n g t o t h e l o a d i n g c h a r a c t e r i s t i c s , etc.

CONCLUSIONS

(1) The f r eezeback of soil around a p i l e f o u n d a t i o n i n p e r m a f r o s t areas d e p e n d s n o t o n l y on the g round t emper - a t u r e , b u t a lso o n t h e t y p e of p i l e foundat ion , method and season of con- s t r u c t i o n , as w e l l as h e a t i n t r o d u c e d by b a c k f i l l e d mater ia l , e tc . I n t h e perma- f r o s t a r e a s of t h e C h i n g h a i - T i b e t P l a t e a u w i t h mean annua l g round t empera tu re lower t h a n -l.O°C, d r i l l e d d r i v e n p i l e s , d r i l l e d p l a c e m e n t p i l e s a n d e v e n c a s t - i n - p l a c e p i l e s c a n h a v e r a p i d n a t u r a l f r e e z e b a c k .

183

I n c o n s t r u c t i o n w i t h c a s t - i n - p l a c e p i l e s , the concre te mix should be near O W i n o r d e r t o r e d u c e t h e n a t u r a l f r e e z e b a c k p rocess . I

( 2 ) Concre t e w i th a low water-cement r a t i o c a n r e a c h Mark 300 by applying c h e m i c a l a d d i t i v e s . I ts index o f resis- t a n c e t o f r e e z i n g a n a t h a w i n g c a n r e a c h o r s u r p a s s "200. I t meets t h e d e s i g n r e g u i r e - ments and creates t h e p o s s i b i l i t y of a wide a p p l i c a t i o n of c a s t - i n - p l a c e p i l e s i n p e r m a f r o s t a r e a s .

(3 ) For p iLe foundat ions in perma- f r o s t , when se t t lement caused by a c e r t a i n v e r t i c a l l o a d makes t h e r e l a x a t i o n o f t h e a d f r e e z i n g f o r c e a t t h e t o p d e v e l o p t o a c e r t a i n d e p t h , a r e a c t i o n f o r c e a p p e a r s a t t h e lower end. If t h e l o a d i n g time is prolonged ox t h e l o a d i n c r e a s e d , t h e r e l a x a t i o n phenomenon w i l l develop con- t i nuous ly . Cor re sponden t ly , t h e r e a c t i o n force a t t h e l o w e r e n d w i l l i n c r e a s e g r a d u a l l y a t t h e same time. All t h e s e show t h a t t h e r e e x i s t s a problem of economic p i l e l e n g t h i n d e s i g n i n g pile f o u n d a t i o n s i n p e r m a f r o s t . F u r t h e r s t u d i e s a r e n e e d e d t o d e t e r m i n e t h e l eng th .

( 4 ) For p i l e s u n d e r a h o r i z o n t a l l o a d i n p e r m a f r o s t , a l t h o u g h c a l c u l a t i o n s common i n soil mechanics do no t en t i re ly conform w i t h r e a l i t y , t h e f o u n d a t i o n m o d u l u s c a n be de t e rmined t h rough f i e ld expe r imen t s and can be used as a s i m p l i f i e d c a l c u l a t i n g method f o r e n g i n e e r i n g d e s i g n . The d i s t r i - bu t ion o f t he founda t ion modu lus i s a c o n c a v e p a r a b o l a a b o v e t h e f i r s t e las t ic zero p o i n t of t h e p i l e and a r e c t a n g l e below it. It conforms f a i r l y w e l l w i t h t h e a c t u a l c o n d i t i o n s . T h e f i r s t e l a s t i c z e r o p o i n t is loca ted be low the f r eeze - thaw i n t e r f a c e a n d t h e d i s t a n c e b e t w e e n t h e s e two i s r e l a t e d t o t h e p i l e d i a m e t e r a n d t h e c h a r a c t e r i s t i c s of t h e f r o z e n soil .

F i g u r e 1.

F i g u r e 2 .

F i g u r e 3.

F i g u r e 4 .

F i g u r e 5.

Geological column and ground t e m p e r a t u r e c u r v e s a t t h e Test S i t e .

Lay o u t o f Test S i t e CH.

Ground t empera tu re cu rve du r ing f r eezeback . (P repa red for d r i v e n p i l e N o . 1 a t T e s t S i t e CB)

Ground t empera tu re cu rve du r ing f r eezeback . (P repa red fo r p l a c e m e n t p i l e N o . 2 a t T e s t S i t e ca)

Freezeback curve o f No. 1 d r i l l e d c a s t - i n - p l a c e p i l e a t Test S i t e CH.

Notes : 1. Data taken

2 0 hours b e f o r e c a s t - i n - p l a c e 1 6 hours a f t e r c a s t - i n - p l a c e

3 days d i t t o 7 days d i t t o

11 days d i t t o 52 days d i t t o 98 a a y s d i t t o

2 . Date o f ca s t - in -p lace : 1 7 h o u r s , J u l y 2 0 , 1 9 7 6 .

F i g u r e 6 . V i e w o f Test S i t e CH.

F i g u r e 7. I n s t a l l a t i o n o f s t a t i c l o a d t e s t .

F igu re 8 . D i s t r i b u t i o n of founda t ion modu lus a long p i l e l eng th

Notes: (a ) n=O K=K

(b ) n=O. 5 K=mZ

(c) n = l K=mZ

( d ) Above t h e f i r s t p o i n t of

0.5

z e r o d i s p l a c e m e n t , n ? l Below d i t t o , n=O

F i g u r e 9 . Comparison between measured and computed bending moments.

F i g u r e 2

F i g u r e 1

F i g u r e 4 Figure 5

Figure 7

F igu re 8

186

187

EXPERIMENTAL ROADBED I N AN AREA WITH A THICK LAYER O F GROUND I C E

R e s e a r c h G r o u p o n E x p e r i m e n t a l R o a d b e d R e s e a r c h , I n s t i t u t e of M i n i s t r y o f Ra i lways , The Peop le ' s Repub l i c of China

ABSTRACT

T h i s p a p e r d e s c r i b e s r e s u l t s from an e x p e r i m e n t a l r o a d b e d a t a s e c t i o n w i t h a t h i c k l a y e r of ground ice - i n a p e r m a f r o s t area a t K u k u s i l i M o u n t a i n i n t h e C h i n g h a i - T i b e t P l a t e a u . T h e e f f e c t s o f u s i n g a small cross s e c t i o n i n a c u t a n d f i l l t o p r e s e r v e a t h i c k l a y e r o f g r o u n d ice w i l l be a n a l y s e d . T h e r e g u l a r i t y o f v a r i a t i o n of t h e p e r m a f r o s t t a b l e a f t e r t h e embankment is c o n s t r u c t e d , e tc . , w i l l a l s o be e v a l u a t e d .

I n C h i n a i n t h e C h i n g h a i - T i b e t P l a t e a u , t h e r e i s e x t e n s i v e c o n t i n u o u s p e r m a f r o s t w i t h t h e h i g h e s t a l t i t u d e above sealevel i n t h e w o r l d . B e c a u s e o f g e o l o g i c a l a n d climatic f ac to r s , t h e s o i l h a s i t s own s p e c i a l h y d r o t h e r m a l c h a r a c t e r i s t i c s a n d t h i c k l a y e r s of ground i c e are p r e s e n t . I n t h i s s e c t i o n t h e r m a l s l i d i n g o r t h e r m a l s e t t l e m e n t w i l l o c c u r , d u e t o n a t u r a l c a u s e s o r human a c t i v i t i e s , c a u s i n g a g r e a t d e a l o f t r o u b l e s b o t h t o road c o n s t r u c t i o n and main tenance . Hence , research work has b e e n c a r r i e d o u t b y c o n s t r u c t i n g a n e x p e r i - men ta l roadbed 4 8 0 m l o n g i n t h e K u k u s i l i Moun ta in (F igu re 1). T h i s p a p e r d e s c r i b e s b r i e f l y t h e d e s i g n p r i n c i p l e s of t h e e x p e r i m e n t a l r o a d b e d i n t h i s area w i t h a t h i c k l a y e r of ground ice , t r e a t m e n t p r o c e d u r e s a n d t h e i r e f f e c t s .

GENERAL CONDITIONS O F EXPERIMENTAL SITE

The expe r imen ta l s i t e is 4 7 8 0 m above sealevel w h e r e t h e p e r m a f r o s t i s r e l a t i v e l y s t a b l e . The geo log ica l and c l imat ic c h a r a c t e r i s t i c s a r e as f o l l o w s :

1. The b a s i c r o c k c o n s i s t s o f p u r p l e r e d s a n d s t o n e a n d m u d s t o n e i n t e r l a y e r s of T e r t i a r y a g e . Above it is Q u a t e r n a r y d e l u v i u m a n d a l l u v i u m o f c l a y e y s a n d a n d s a n d y c l a y , g e n e r a l l y 3 - 5 m th i ck . The p e r m a f r o s t t a b l e i s u s u a l l y 1 . 3 - 1 . 6 m b e l o w t h e g r o u n d s u r f a c e a n d i n c r e a s e s t o a b o u t 2 rn b e n e a t h d i t c h e s w i t h f l o w i n g water. An ice l a y e r a b o u t 1 - 3 rn t h i c k is u s u a l l y f o u n d j u s t below t h e p e r m a f r o s t table . T h e t h i c k n e s s of t h e p e r m a f r o s t i s a b o u t 80 - 1 2 0 m.

2 . The mean annual a i r t e m p e r a t u r e i s -4% t o -6OC a n d t h e mean annual. g r o u n d t e m p e r a t u r e i s -2.5OC ( F i g u r e 2 ) . The per iod of n e g a t i v e t e m p e r a t u r e i n 1976 was 255 d a y s a n d o f p o s i t i v e t e m p e r - a t u r e w a s 1 1 0 days . The f r eez ing i ndex was 2640 d e g r e e (OC) d a y s , t h e t h a w i n g i n d e x was 280 d e g r e e d a y s a n d t h e r a t i o of f r e e z i n g i n d e x t o thawing index w a s 9 . 4 . T h e n a t u r a l g r o u n d s u r f a c e f r e e z i n g index w a s 2314 d e g r e e d a y s , a n d t h e t h a w - i n g i n d e x was 7 6 8 d e g r e e d a y s ( F i g u r e 3 ) . C a p a b i l i t y of a n n u a l f r o s t d e p t h w a s much g r e a t e r t h a n t h a t of annua l t haw dep th .

3 . P r e c i p i t a t i o n i s p r i m a r i l y i n t h e f o r m of snow, mostly i n J u n e , J u l y , A u g u s t a n d S e p t e m b e r . T h e a n n u a l p r e c i p i t a t i o n i s 300 - 4 0 0 mm, a n d a n n u a l e v a p o r a t i o n i s 1200 - 1 4 0 0 mm.

4 . S o l a r r a d i a t i o n i s h i g h , e s p e c i a l l y i n t h e w a r m s e a s o n s . From A p r i l t o O c t o b e r , t h e mean d a i l y r a d i a t i o n e x c e e d s 4 0 0 kcal /cm2 day. The July radia- t i o n i s l. 8 times t h a t of December. The t o t a l r a d i a t i o n i n 1 9 7 6 w a s 1 4 1 kcal /cm2, among of w h i c h d i r e c t r a d i a t i o n a m o u n t e d t o 8 8 . 1 k c a l / c m 2 y e a r a n d d i f f u s e r a d i a - t i o n t o 5 2 . 7 kcal/cm2.

T h u s , t h e e x p e r i m e n t a l s i t e p o s s e s s e s n a t u r a l c h a r a c t e r i s t i c s o f l o w a i r and g r o u n d t e m p e r a t u r e , l a r g e r q u a n t i t y of h e a t d i s p e r s i o n t h a n a b s o r p t i o n a t t h e g r o u n d s u r f a c e , g r e a t e r t h i c k n e s s p e r m a f r o s t , h i g h water and ice c o n t e n t i n t h e s o i l nea r and a few metres benea th t he pe rma- f r o s t table, etc . F o r t h e s e r e a s o n s , t h e p r i n c i p l e of e x p e r i m e n t a l r o a d b e d d e s i g n i n c u t s i s t o p r o t e c t t h e t h i c k l a y e r of ground ice and ice r i c h f r o z e n s o i l a n d ma in ta in t hem i n a f r o z e n s t a t e . An i n s t a l l e d r e i n f o r c e d c o n c r e t e L - s h a p e d r e t a i n i n g wal l a n d m a s o n r y r e t a i n i n g wa l l , a s w e l l as a d r a i n a g e s y s t e m were a l so c o n s t r u c t e d .

I n order t o i n v e s t i g a t e t h e c o n - s t r u c t i o n t e c h n i q u e of a r o a d b e d i n a n area wi th g round ice d u r i n g t h e t h a w i n g s e a s o n , t h e e x p e r i m e n t a l r o a d b e d s were b u i l t d u r i n g t h e p e r i o d from May t o September .

188

After the experimental roadbeds were completed, thermocouple cables, sensit ive resis tance thermometer uni ts together with heat f low, heat conductance and moisture content measuring apparatus were i n s t a l l e d . In addi t ionIan automatic remote monitor ing device was a l so p rovided for per iodic observat ion.

TREATMENTS ON EXPERIMENTAL CUT AND ANALYSIS OF THEIR EFFECTS

Two types of c r o s s s e c t i o n were adopted for the experimental cut : s ide- s lopes and subgrade with insulation (Figures 4 and 5 ) ; s ides lopes wi th reve tment counter for t and subgrade with insu la t ion (F igure 6 ) .

1. Cross sec t ion of b a c k f i l l e d s i d e - s lope and subgrade with insulat ion.

For t h i s t y p e of c r o s s s e c t i o n , t h e most important matter i s to de te rmine t h e t h i c k n e s s of t h e b a c k f i l l e d l a y e r , which is worked ou t by the empir ica l formula:

where h --

1 . 2 -- Kl

"

K2 --

K3 --

Hmax --

t h i ckness of b a c k f i l l e d l a y e r (m) s a f e t y c o e f f i c i e n t back f i l l ed ma te r i a l modifying coeff ic ient or ien ta t ion modi fy ing c o e f f i c i e n t sur face fea ture modi fy ing c o e f f i c i e n t maximum depth of natural permafros t t ab le in a t y p i c a l s i t e (good vege ta t ion and open plain1 fo r yea r s , i n metres.

Determination and selection o f va lues sax, K1, K 2 , and K3 a r e b r i e f l y s t a t e d a s follows:

1) Determination o f Hmax

(1) When it is determined by SUP- veying, the natural depth of the permafrost table should be modified by adding the tempera ture f luc tua t ion , i .e. ,

Hmax =

where H --

AH --

a --

depth of natural permafrost t ab l e ob ta ined by surveying, i n metres increment of depth o f natura l permafros t t ab le due to t empera ture f l u c t u a t i o n , i n metres s t a t i s t i c a l c o e f f i c i e n t determined by local geo- l o g i c a l c o n d i t i o n s , i n m/OC

T -- mean annual temperature of

TH -- mean annual temperature of P designed frequency, i n OC

the observing year i n OC

( 2 ) I t may be c a l c u l a t e d a l s o by the fol lowing formula:

Ifmax = aE8 + b ................ ( 3 )

where E , -- mean monthly temperature ( O C ) of the experimental s ec t ion i n Augus t r e l a t ing to designed f requency

I t may be found in Table 1.

a -- empi r i ca l coe f f i c i en t (m/OC) from s t a t i s t i c a l d a t a a = 0 . 1 m/oC

b -- empi r i ca l coe f f i c i en t ( m l , from s t a t i s t i c a l d a t a b = 0 . 8 5 m

The ac tua l da t a r eco rded ove r s ix y e a r s , v e r i f i e d t h a t t h e maximum abso lu te dev ia t ion of c a l c u l a t e d Elmax by using Formula ( 3 ) i s 9 cm and t h e maximum r e l a t i v e d e v i a t i o n i s 70% (Table 2).

2 ) Determination of K1

wi th pea t and subgrade with insulation (1) For a s lope surface covered

K1 i s obtained by the fol lowing formula:

I T

Z d+ (Hma,-d)J a' K1 =- = Hmax Hmax

*. . * ( 4 )

where

t i o n ,

where

2 --

d --

a --

a ' --

thickness of peat and soi l l ayer conver ted in to th ick- n e s s of b a c k f i l l e d m a t e r i a l above the natural permafrost t a b l e , i n metres p e a t t h i c k n e s s a t t y p i c a l s i t e ( m ) thermal conduct ivi ty o f b a c k f i l l e d m a t e r i a l i n thawing state (m2/sec) thermal conduct ivi ty of s o i l layer i n thawing s ta te (m*/sec)

( 2 ) For t h e homogeneous i n s u l a -

"max "max

a -- thermal conduct ivi ty of p e a t l a y e r i n t h a w i n g s t a t e (m2/ sec

o t h e r s -- as above

189

! I n s u r a n c e (8) 0 . 1 I 1 2 5 1 0 2 0 50 90 95 9 9

'

R e c u r r i n g P e r i o d ( y e a r ) 1 0 0 0 1 0 0 50 2 0 1 0 5 2 10 2 0 100

- t* (OC) 7.6 6.9 6.6 6.3 6 .0 5.7 5.1 4 . 2 4.0 3.6

Table 1 Mean t e m p e r a t u r e of t h e e x p e r i m e n t a l s e c t i o n i n A u g u s t a c c o r d i n g t o d e s i g n e d f r e q u e n c y

I Year 1 1966 1 1967 1 Actual ( ;yasured 1 1 . 4 9 I 1 . 3 8

C a l c u l a t e d (m) 1 . 4 1 1 .38

A b s o l u t e d e v i a t i o n 8 0 ( c m )

Relative d e v i a t i o n 6 . 1 0 ( % I

I 2 - 3 I 3 - 5

I

1 9 7 6

1.30

1 . 2 1

9

6.9

Table 2 D e v i a t i o n b e t w e e n a c t u a l d a t a a n d c a l c u l a t e d v a l u e of n a t u r a l p e r m a f r o s t t ab l e

1977

1.34

1.31

3

2 . 2

O r i e n t a t i o n Open P l a i n Sunny S lope Shaded S lope

Grade 0 1 ~ 1 . 5 - 1 ~ 1 . 7 5 L t 1 . 5 - 1:1 .75

K 2 1 . 0 0 1.10 0.85

Table 3 O r i e n t a t i o n m o d i f y i n g c o e f f i c i e n t s

3 ) S e l e c t i o n o f K 2

K2 i s r e l a t e d t o i n s o l a t i o n . T t s h o u l d be c a l c u l a t e d b y t h e t h a w i n g i n d e x a t t h e g r o u n d s u r f a c e o f similar s u r f a c e f e a t u r e s a n d d i f f e r e n t o r i e n t a t i o n a n d s l o p e . T h e o r i e n t a t i o n m o d i f y i n g c o e f f i c - i e n t s w h i c h were o b t a i n e d , a x e shown i n Table 3 .

4 ) S e l e c t i o n of K 3

K i s r e l a t e d t o t h e s u r f a c e h e a t 3 a b s o r p t i o n a n d r e f l e c t i o n . I t sh0ul.d be

c a l c u l a t e d by t h e t h a w i n g i n d e x a t t h e g r o u n d s u r f a c e o f similar o r i e n t a t i o n , s l o p e a n d d i f f e r e n t s u r f a c e f e a t u r e s . S u r f a c e fea ture m o d i f y i n g c o e f f i c i e n t s which were o b t a i n e d are shown i n T a b l e 4 .

I n o r d e r t o p l a c e t h e i n s u l a t i o n i n t h e w a r m season, t h e ice l a y e r , e x p o s e d d u r i n g c o n s t r u c t i o n , w a s c o v e r e d by a L i g h t i n s u l a t i n g c u r t a i n as a t e m p o r a r y p r o t e c t i o n ; t h u s t h e t h a w i n g r a t e was r e d u c e d ( F i g u r e 7 ) . The face o f t h e s l o p e s r e m a i n e d s tab le d u r i n g t h e c o n s t r u c t i o n p e r i o d a n d were p r e s e r v e d .

190

Clayey Polysty- Bitumen Sand Aerated

C o a t i n g Peat Material

P e a r l i t e w i t h C o n c r e t e r e n e Foam Pla te Gravel P l a t e P la te

Colour G r e y i s h Brown G r e y i s h White Y e l l o w i s h g r e e n b l a c k w h i t e

Surf ace Smooth Coarse Rough Smooth Fe l t

K 3 1 . 0 0 1 .18 1 . 1 6 0 . 9 4 0 . 8 2

T a b l e 4 S u r f a c e f e a t u r e m o d i f y i n g c o e f f i c i e n t

C o n s t r u c t i o n p r a c t i c e a n d o b s e r v e d d a t a f o r 2 - 3 y e a r s a f t e r c o m p l e t i o n of t h e c u t show t h a t s u c h d e s i g n i n g p r i n c i p l e s , c a l c u l a t i n g m e t h o d a n d t r e a t m e n t c a n m a i n - t a i n t h e s t a b i l i t y o f a c u t i n a n area w i t h a t h i c k l a y e r of ground ice.

The i n i t i a l c o n c l u s i o n s a re as f o l l o w s :

1) A f t e r c o n s t r u c t i o n of t h e e x p e r i m e n t a l r o a d b e d , t h e maximum d e p t h o f s e a s o n a l t h a w i n v a r i o u s t y p e s of s i d e - s l o p e i s 0 .7 6 - 1 . 8 5 m , which meets t h e design needs. However , when i n d u s t r i a l i n s u l a t i n g material i s u s e d , i t s low t h e r m a l c o n d u c t i v i t y e f f e c t i v e l y r e d u c e s t h e t h a w i n t h e s i d e s l o p e a n d s u b g r a d e . Among t h e s i x t y p e s o f i n s u l a t i n g materials u s e d i n t h e e x p e r i m e n t a l r o a d b e d , t h e i n s u l - a t i n g p r o p e r t i e s o f t h e r i g i d foam p l a s t i c p l a t e , p l a s t i c p e a r l i t e c o n c r e t e p l a t e a n d a e r a t e d c o n c r e t e p l a t e w i t h water p r e s e r v - i n g t r e a t m e n t are m o s t e f f e c t i v e . B e n e a t h t h e s i d e s l o p e , t h e maximum d e p t h of s e a s o n a l t h a w is reduced by 0 .7 - 3.1 m c o m p a r e d w i t h t h a t w h e r e c l a y i s u s e d a s b a c k f i l l mater ia l . F o r e x a m p l e , t h e d e p t h o f t h a w i n a s u n n y s l o p e p r o t e c t e d b y a p o r o u s c o n c r e t e p l a t e i s 0.98 m less t h a n t h a t b y c l a y m i x e d w i t h c r u s h e d s t o n e . I t s mean thaw r a t e is o n l y 6 5 % of t h a t a t a n a t u r a l s i te . The mean monthly temper- a t u r e d i f f e r e n c e b e t w e e n t h e u p p e r a n d lower f a c e s a m o u n t s t o l l ° C , which i n d i c a t e s good i n s u l a t i n g v a l u e s o f t h e i n s u l a t i o n material .

2 ) Because of i t s low thermal c o n d u c t i v i t y ( o n l y o n e - h a l f t h a t o f the soil), p e a t h a s b e e n u s e d as a n i n s u l a t i n g m a t e r i a l . I t s amount of heat consumption i s i n c r e a s e d b y p h o t o s y n t h e s i s a n d e v a p o r - a t i o n : i t s roots l o o s e n t h e s u r r o u n d i n g soil c a u s i n g i n c r e a s e d water a b s o r p t i o n a n d l a t e n t h e a t of t h a w i n g . T h e r e f o r e , when p e a t i s used as b a c k f i l l , t h e maximum d e p t h o f s e a s o n a l t h a w i n side- slopes i s reduced by 1 4 % ( 0 . 3 - 0 . 4 ml

c o m p a r e d w i t h t h a t of l oca l s a n d y c l a y m i x e d w i t h c r u s h e d s t o n e . D u r i n g t h e warm season , t he amoun t of r a i n f a l l is a b u n d a n t i n t h e C h i n g h a i - T i b e t P l a t e a u , which i s advantageous t o t h e g r o w t h of t h e p e a t a f t e r t r a n s p l a n t i n g . Two y e a r s a f t e r c o n s t r u c t i o n , t h e roo ts i n t e r w e a v e i n t o a s i n g l e s h e e t a n d t h e s i d e s l o p e i s f u r t h e r s t a b i l i z e d .

2 . Cross s e c t i o n of t h e s i d e s l o p e w i t h r e v e t m e n t s t r u c t u r e a n d s u b g r a d e w i t h i n s u l a t i o n .

T h e r e a r e two t y p e s of r e v e t m e n t s t r u c t u r e f o r t h i s so r t of cross s e c t i o n . One i s a m a s o n r y r e t a i n i n g wal l a n d t h e o t h e r i s an i n s t a l l e d (1 m w i d e p e r p i e c e ) L - s h a p e d r e i n f o r c e d c o n c r e t e t h i n p l a t e r e v e t m e n t .

For t h e L - s h a p e d r e i n f o r c e d c o n c r e t e r e v e t m e n t s t r u c t u r e , it s h o u l d be f i l l e d w i t h sand a n d g r a v e l , t h e g r a v e l c o n t a i n i n g c l a y e y s a n d s t o n e f r a g m e n t s a n d soil s l u r r y . The founda t ion shou ld be b u r i e d 0 . 2 - 0.4 m below t h e c a l c u l a t e d p e r m a f r o s t table , or a t s u f f i c i e n t d e p t h t o m a i n t a i n t h e f o o t i n g i n a f r o z e n s t a t e a n d u t i l i z i n g t h e w e i g h t of t h e b a c k f i l l e d s o i l t o overcome soil s w e l l i n g a n d f r o s t h e a v e f o r c e s .

I n o r d e r t o i n v e s t i g a t e t h e force a c t i n g o n t h e r e t a i n i n g w a l l and i t s d e f o r m a t i o n , n i n e force m e a s u r i n g u n i t s were i n s t a l l e d b e h i n d t h e r e t a i n i n g wall a l o n g i t s h e i g h t a n d t h e d i s p l a c e m e n t was m e a s u r e d i n f r o n t of t h e s t r u c t u r e . A t t h e same t i m e i n s i t u tests were a l so c a r r i e d o u t on t h e m o d e l r e t a i n i n g wall a n d l o a d i n g s e n s o x s were u s e d t o make o b s e r v a t i o n .

From o b s e r v a t i o n s over t w o y e a r s , i n i t i a l c o n c l u s i o n s are a s f o l l o w s : -

191

1 I Mean Freez- Mean Thawing V a r i a t i o n of

C o n s t r u c t i o n C o n s t r u c t i o n f o l l o w i n g T a b l e i n t h e c r o s s P e r i o d H e i g h t Year Pea r Cons t ruc t ion Section (month) (m 1 Ccm/day) (crn/day) Year ( m )

i ng Ra te of R a t e i n t h e P e r m a f r o s t

0 + 215 June- 1.3 5 . 1 1 . 1 5 Rise - 1 . 0 J u l y

0 -k 280 J u l y - 5 . 4 3 .0 1.53 Drop - 0.25 sept.

b

Table 5 I n f l u e n c e of c o n s t r u c t i o n s e a s o n on permafros t under subgrade

1) The l a t e r a l normal f r o s t h e a v e f o r c e a c t i n g o n t h e r e t a i n i n g w a l l i s r a t h e r h i g h a n d v a r i e s s i g n i l c a n t l y w i t h depth f rom 0 . 0 1 - 2.63 kg/cm . I n com- p a r i s o n w i t h t h e p r e s s u r e of thawed s o i l a t t h e same d e p t h , t h e l a t e r a l n o r m a l f r o s t h e a v e f o r c e i s g e n e r a l l y 10 times o r even up t o a maximum of 3 5 times t h e s o i l p r e s s u r e .

5 '

The l a t e r a l normal f r o s t h e a v e f o r c e acts main ly upon the middle and l o w e r p a r t s of t h e r e t a i n i n g s t r u c t u r e .

2 ) The l a t e r a l normal f r o s t h e a v e f o r c e h a s a c o n s p i c u o u s c h a r a c t e r i s t i c of r e l a x a t i o n ( F i g u r e 1 0 ) .

THERMAL ANALYSIS OF EXPERIMENTAL EMBANKMENT

Embankments of d i f f e r e n t h e i g h t were cons t ruc ted f rom 0 t o 9 m a n d i n s u l a t i o n tests were c a r r i e d o u t a t t h e e x p e r i m e n t a l s i te t o i n v e s t i g a t e t h e f o r m a t i o n o f a " f r o z e n c o r e " a n d t h e r e g u l a r i t y o f v a r i a - t i o n i n t h e embankment. A f t e r c o n s t r u c t i o n was completed, thermal observat ions were c a r r i e d o u t t o g e t h e r w i t h t h o s e o n a neut ron mois tuxe meter water gauge, e lectr ic probe , etc. f o r m o n i t o r i n g t h e m o i s t u r e m i g r a t i o n and t o measu re su r f ace de fo rma t ion . From t h e c o n q t r u c t i o n a n d t h e r m a l a n a l y s i s , t h e fo l lowing conc lus ions were ob ta ined :

1. Pe rmaf ros t benea th t he embankment subgrade is in f luenced by t h e c o n s t r u c t i o n season t o a c e r t a i n e x t e n t . When t h e embankment i s constructed and completed d u r i n g t h e l a t t e r p a r t o f t h e w a r m season , t h e p e r m a f r o s t b e n e a t h t h e s u b g r a d e may t h a w l o c a l l y r e s u l t i n g i n a n i n c r e a s e o f embankment s e t t l e m e n t . T h i s is d u e t o t h e depth of thaw i n n a t u r a l g r o u n d b e i n g comparatively g r e a t (70% - 80% o f t h e s e a s o n a l d e p t h o f thaw by the end o f J u l y ) ; the h e a t

s t o r e d i n t h e ground i s c o n s i d e r a b l e and h e a t b r o u g h t i n t o t h e embankment by t h e b a c k f i l l i s h a r d t o d i s s i p a t e . M o r e o v e r , t h e f r e e z i n g r a t e i n t h e same yea r i s also af fec ted . For ah embanhnent less than 9 m h i g h , t h e h e a t s t o r e d is e n t i r e l y consumed a f t e x o n e o r two years , and the thaw rate i s b a s i c a l l y p r o p o r t i o n a l t o t h e h e i g h t of t h e embankment. However, t h e zone with ze ro deg ree t empera tu re still r e m a i n s i n the middle and lower par t s o f t h e embankment and w i l l g r a d u a l l y d i s a p p e a r a f t e r t h r e e y e a r s .

The t e c h n i c a l d a t a of embankment c o n s t r u c t e d i n J u n e a n d J u l y ( c r o s s s e c t i o n 0 + 215) compared t o t h a t b u i l t f rom Ju ly t o September (cross s e c t i o n 0 + 2 8 0 ) a r e g i v e n i n T a b l e 5, F i g u r e s 11 and 1 2 .

2 . The h e i g h t o f t h e embankment d i r e c t l y i n f l u e n c e s the d e p t h o f f r e e z i n g and thawing. Based upon the obse rved da ta f rom twelve embankments of d i f f e r e n t h e i g h t s f i l l e d w i t h a c l a y g r a v e l m i x t u r e , t h e f o l l o w i n g r e l a t i o n s h i p is d e r i v e d s t a t i s t i c a l l y :

1) The r e l a t i o n b e t w e e n embankment h e i g h t H (i8 m) and t h e r i s i n g 0 of t h e p e r m a f r o s t t a b l e i s

u = 1.02H - 0.5 . .... ....... (6) The c r i t i c a l h e i g h t of t h e embank-

ment w h e r e t h e o r i g i n a l p e r m a f r o s t t a b l e remains unchanged i s 0 . 5 m. The minimum h e i g h t o f t h e e m b a n m e n t w h e r e t h e " f r o z e n core" e x t e n d s i n t o t h e embankment i s 1 .8 - 2 . 6 m.

The above r e l a t ionsh ip does no t a g r e e w i t h t h e o - H obtained from thaw u n s t a b l e s o i l embankments a t v a r i o u s loca t ions a long t he Ch ingha i -T ibe t H ighway.

192

Embankment H e i g h t

( m )

5 . 4

4 . 6

3.0

Amount o f Mean F r e e z i n g Rate i n S t o r e d Heat C o n s t r u c t i o n Year Mean Thaw

i n Embank- (cm/day) Rate i n

P e r i o d Fol lowing

L i n e a r Metre F r e e z i n g B a c k f r e e z i n g (month)

Year C o n s t r u c t i o n m e n t p e r

(kcn l ) f rom above from below (cm/day) I I I I I

J u l y - S e p t . I 3.85 X l o 5 I 3 .0 1 1 . 6 1 1.53

11 2 .7 x 10 I 3.3 I 1.8 j 1.37

T a b l e 6 I n f l u e n c e of embankment h e i g h t o n f r e e z i n g r a t e of t h e c o n s t r u c t i o n y e a r a n d t h a w i n g

r a t e o f t h e f o l l o w i n g y e a r

2 ) The r e l a t i o n b e t w e e n embankment h e i g h t H (0 .5m~Hi8m) and maximum d e p t h of s e a s o n a l t h a w h a t t h e c e n t r e of t h e embankment i s max

hma, = 0 . 1 5 H t 1.8 . . . . . . * . ( 7 )

3 ) The influence of embankment h e i g h t o n f r e e z i n g r a t e i n t h e c o n s t r u c t i o n yea r and t hawing r a t e o f t h e f o l l o w i n g y e a r i s g i v e n i n T a b l e 6 .

3 . H is d u e t o t h e i n f l u e n c e o f s i d e - s l o p e o r i e n t a t i o n a n d s u b g x a d e s u r f a c e u n e v e n n e s s ; t h e a r t i f i c i a l u p p e r b o u n d a r y i n t h e embankment may be a c u r v e i n c l i n e d t o b o t h s i d e s o r a l i n e i n c l i n e d t o o n e s i d e . B o t h a re d e t r i m e n t a l t o t h e s t a b i l i t y o f t h e s i d e s l o p e . When t h e s h o u l d e r i s f a c i n g t h e s u n , i t s d e p t h of thaw w i l l be a t a maximum ( 1 . 2 - 1 . 4 times t h a t of t h e r o a d b e d c e n t r e ) b e c a u s e t h e h e a t c o n d u c t i o n is a two-dimensional problem. Moreover, t h e u p p e r b o u n d a r y of t h e s i d e - s l o p e a n d s u b g r a d e s u r f a c e i s c o n n e c t e d w i t h a c u r v e . On t h e o t h e r h a n d , t h e upper thaw depth of t h e s h o u l d e r a t t h e s h a d e d s i d e i s close t o t h a t of t h e r o a d b e d c e n t r e ( 0 . 9 - 1 . 0 times t h a t of t h e r o a d - b e d c e n t r e ) . T h e r e f o r e , t h e f r e e z e - t h a w i n t e r f a c e i n c l i n e s g r a d u a l l y from t h e s h o u l d e r of t h e s h a d e d s l o p e t o w a r d t h a t of t h e s u n n y s i d e (or r o a d b e d c e n t r e ) , f o r m i n g a n a n g l e w i t h t h e h o r i z o n g r e a t e r t h a n 6 0 ( a c t u a l m e a s u r e d v a l u e i s 8 O ) . When ice a c c u m u l a t i o n a t t h e u p p e r b o u n d a r y is s u f f i c i e n t a n d t h e s i d e d i t c h c a n n o t d r a i n e f f e c t i v e l y , a s p l i t a l o n g t h e s h o u l d e r o r even a s i d e s l o p e s l i de w i l l r e s u l t . I n t h i s c a s e , t h e s t a b i l i t y of a s t e e p s i d e s l o p e a n d h i g h embankment must be checked and local i n s u l a t i o n o r a berm s h o u l d be p r o v i d e d i f n e c e s s a r y .

4. T h r o u g h a n o b s e r v a t i o n p e r i o d o f t w o t o t h r e e y e a r s , t h e v a r i a t i o n i n m o i s t u r e c o n t e n t i n t h e embankment i s n o t s i g n i f i c a n t b e c a u s e t h e c o m p a c t e d d e n s i t y a h d moisture c o n t e n t h a v e b e e n c o n t r o l l e d d u r i n g c o n s t r u c t i o n . F u r t h e r - more, t h e t y p e of c r o s s s e c t i o n of t h e embankment i s a l so conducive t o dessica- t i o n .

5. I n s u l a t i o n may r e d u c e t h e d e p t h of thaw and f r o s t h e a v e . I n t h e e x p e r i m e n t a l embankment w i t h a r i g i d foam p l a s t i c p l a t e , t h e c u r v e of t h a w i n g b e n e a t h t h e i n s u l a - t i o n shows a s i g n i f i c a n t t u r n . D u r i n g t h e e a r l y p a r t of t h e w a r m s e a s o n , t h e thaw ra te i s fas te r t h a n i n t h e c o n v e n - t i o n a l embankment; however, as soon a s t h e O°C i s o t h e r m p a s s e s t h r o u g h t h e i n s u l a t i n g l a y e r , t h e t h a w r a t e r e d u c e s q u i c k l y so t h a t t h e maximum d e p t h of s e a s o n a l t h a w i s 2 0 - 3 0 % less t h a n t h a t of t h e c o n v e n t i o n a l s o i l embankment and t h e t h i c k n e s s o f t h e f r o s t heave zone i s r e d u c e d ( F i g u r e s 13 and 1 4 ) . A t t h e same time, t h e f r e e z i n g rate of t h e soil above t h e i n s u l a t i n g l a y e r i s a l so i n c r e a s e d i n w i n t e r , r e d u c i n g m o i s t u r e m i g r a t i o n a b o v e t h e i n s u l a t i o n . M o i s t u r e m i g r a t i o n b e n e a t h t h e i n s u l a t i o n i s i n t e r c e p t e d . C o r r e s p o n d i n g l y t h e a m o u n t o f f r o s t h e a v e i n t h e embankment i s reduced .

SUBGFL4DE DRAINAGE SYSTEM AND I T S EFFECTS

Accord ing t o t h e climate and c h a r a c t e r i s t i c s of t h e p e r m a f r o s t a t t h e working s i te , a side d i t c h i n t h e s u b g r a d e , c u t - o f f d i k e a n d i n t e r c e p t i n g d i t c h on t h e u p h i l l s i d e were i n c o r p o r a t e d t o d r a i n ox i n t e r c e p t t h e water.

193

The cross s e c t i o n of t h e s i d e d i t c h i s g e n e r a l l y 0 . 4 - 0.6 m w i d e ( a t t h e b o t t o m ) , 0 .4 m deep and i t s s i d e s l o p e i s 1:l. The bo t tom and s ide a re c o v e r e d w i t h p e a t or sealed w i t h c l a y . A f t e r t w o t o t h r e e y e a r s o f o b s e r v a t i o n , it was found that d e f o r m a t i o n was n o t s i g n i f i c a n t a n d t h e d e p t h of t h a w b e n e a t h t h e b o t t o m of t h e d i t c h d e s c e n d e d o n l y 0 . 1 - 0.2 m c o m p a r e d w i t h t h e p e r m a f r o s t t a b l e .

I n t h e case of t h e d e e p c u t , t h e c u t - o f f d i k e o b t a i n e d g o o d r e s u l t s b y u t i l i z i n g t h e e a s y f o r m a t i o n o f a “ f r o z e n core” i n t h i s area t o i n t e r c e p t a n d d r a i n t h e water a b o v e t h e l a y e r a l o n g t h e o p p o s i t e f r o z e n s l o p e t o p r e v e n t it from f l o w i n g i n t o t h e s i d e s l o p e . The d imens ions of t h e c u t - o f f d i k e a r e : c e n t r e h e i g h t 0 .8 - 1 . 0 m , w i d t h o f u p p e r s u r f a c e 0 .6 - 1 . 0 m a n d s i d e s l o p e 1 : 1 . 5 .

CONCLUSIONS

From t h e d e s i g n , c o n s t r u c t i o n a n d a c t u a l o b s e r v a t i o n of t h e s e e x p e r i m e n t a l s o a d b e d s , t h e m a i n c o n c l u s i o n s c a n b e s t a t e d as follows:

1. T h e m a i n p r i n c i p l e of d e s i g n i n g a r o a d b e d i n a n area w i t h a t h i c k l a y e r o f ground ice a n d r e l a t i v e l y s t a b l e perma- f rost , is t o p r o t e c t a n d m a i n t a i n t h e ice and ice r i c h f r o z e n s o i l i n t h e f r o z e n s ta te . T h e f o l l o w i n g e m p i r i c a l f o r m u l a may be used t o d e t e r m i n e t h e t h i c k n e s s o f t h e b a c k f i l l e d L a y e r :

h = 1.2K1K2K3Hmax

The ca l cuLa t ion o f t h e a b o v e f o r m u l a i s s i m p l e a n d t h e p a r a m e t e r s i n v o l v e d i n t h e c a l c u l a t i o n a x e e a s i l y obtained. However , f o r a n i m p o r t a n t s i t e s u c h a s a deep cu t and h igh embankmen t , a t w o - d i m e n s i o n a l m a t h e m a t i c a l a n a l y s i s or a n a p p r o x i m a t i o n of g r e a t e r a c c u r a c y m u s t b e d e r i v e d t o d e t e r m i n e t h e t o p b o u n d a r y o f t h e p e r m a f r o s t . T h i s w i l l l e a d t o a r e a s o n a b l e s e l e c t i o n of t h e cross s e c t i o n .

2 . I n d u s t r i a l i n s u l a t i o n h a s a more p r o m i n e n t e f f e c t o n r e d u c i n g t h e c u t s e c t i o n a n d d e p t h o f t h a w . I f b a c k f i l l e d material i s a v a i l a b l e l o c a l l y , p e a t or coarse a n d f i n e g r a i n so i l may be also used .

3. I n d e s i g n i n g a r e t a i n i n g s t r u c t u r e , full a t t e n t i o n m u s t be paid t o l a t e r a l n o r m a l f r o s t h e a v e .

4 . A t t h e e x p e r i m e n t a l s i t e , a f t e r t h e 0 . 5 t o 9 m h i g h embankment was comple ted , t h e a r t i f i c i a l upper boundary

o f t h e p e r m a f r o s t was r i s i n g . When t h e b a c k f i l l e d material i s c l a y e y soil, t h e r e l a t i o n b e t w e e n t h e r i s i n g h e i g h t o f t h e a r t i f i c i a l u p p e r b o u n d a r y a n d t h e embank- m e n t h e i g h t H i s

C- = 1.02H - 0 . 5

Namely, t h e minimum h e i g h t of t h e embankment where t h e o r i g i n a l p e r m a f r o s t t a b l e r e m a i n s u n c h a n g e d i s 0,5 m ; t h e c r i t i c a l h e i g h t o f t h e embankment where t h e “ f r o z e n c o r e “ e x t e n d s i n t o t h e embankment i s a b o u t 1 . 8 m f o r c l a y e y so i l and a b o u t 2 . 6 m f o r c o a r s e g r a i n e d so i l . But a t t e n t i o n s h o u l d b e p a i d t o t h e f o l l o w i n g c o n d i t i o n s :

When t h e embankment i s c o n s t r u c t e d a n d c o m p l e t e d d u r i n g t h e l a t t e r p a r t of t h e warm s e a s o n , a s o f t e n as n o t t h e a r t i f i c i a l u p p e r b o u n d a r y o f t h e p c r m a - f r o s t w i l l d r o p d u r i n g t h e c o n s t r u c t i o n y e a r d u e t o t h e p o t e n t i a l h e a t of s e a s o n a l l y t h a w e d l a y e r a n d f i l l materials.

5. I n t h i s area, p r o v i d e d a d e q u a t e p r o t e c t i n g m e a s u r e s a re be ing t aken and a t t e n t i o n p a i d t o t h e o r g a n i z a t i o n a n d p r o c e d u r e s o f c o n s t r u c t i o n , b o t h c u t s a n d embankments i n area w i t h t h i c k g r o u n d ice c a n b e c o n s t r u c t e d d u r i n g t h e w a r m s e a s o n .

F i g u r e 1.

F i g u r e 2 .

F i g u r e 3 *

F i g u r e 4 .

F i g u r e 5

F i g u r e 6 .

F i g u r e I .

C o n s t r u c t i o n s i t e of e x p e r i m e n t a l r o a d b e d .

M o n t h l y v a r i a t i o n s i n g r o u n d t e m p e r a t u r e .

A i r and ground tempera ture p r o c e s s i n g c u r v e s .

C r o s s s e c t i o n o f e x p e r i m e n t a l roadbed .

I I I(

Cross s e c t i o n of r e t a i n i n g s t r u c t u r e .

T e m p e r a t u r e v a r i a t i o n of s i d e - s l o p e w i t h t e m p o r a r y i n s u l a t i n g c u r t a i n

Notes 1.

2 .

3.

T e m p e r a t u r e v a r i a t i o n of n a t u r a l g r o u n d s u r f a c e i n p l a i n . T e m p e r a t u r e v a r i a t i o n of s i d e s l o p e s u r f a c e f a c i n g s u n s h i n e w i t h cover d u r i n g day time and opened a t n i g h t . T e m p e r a t u r e v a r i a t i o n of s i d e s l o p e s u r f a c e f a c i n g s u n s h i n e w i t h cover b o t h during day time and a t n i y h t ,

194

F i g u r e 7.

Notes

F i g u r e 8.

Notes

F i g u r e 9 .

Notes

( c o n t d) 4 . T e m p e r a t u r e v a r i a t i o n of

s i d e s l o p e s u r f a c e € a c i n g sunsh ine w i thou t cover.

Mean monthly ground temperature I

’* /- conc re t e , sunny s ide -

2 . , ‘ t y p i c a l n a t u r a l s i te ,

p r o t e c t e d by aerated

s l o p e .

/ o p e n p l a i n w i t h good v e g e t a t i o n .

Thaw cu rves

a ---- p r o t e c t e d by a e r a t e d conc re t e , sunny s ide - s l o p e .

b ---- t y p i c a l n a t u r a l s i t e , open p l a i n wi v e g e t a t i o n .

F i g u r e 1 0 . Re laxa t ion cu rve o f normal f r o s t heave.

t h good

F i g u r e 11. V a r i a t i o n s i n g r o u n d and mo i s tu re con ten t i n s e c t i o n 0 + 2 1 5 .

F igu re 1 2 . V a r i a t i o n s i n g r o u n d and mois ture conten t i n s e c t i o n 0 + 280.

l a t e r a l

t empera ture wi th dep th

tempera ture wi th dep th

F i g u r e 13 . Thaw curves .

195

F i g u r e 2

F i g u r e 3.

Figure 3

F i g u r e 4

7 96

F i g u r e 5

Figure 7

Figure 9

F igu re 6

F igu re 8

197

198

199

EXPERIMENTAL RESEARCH ON AN EMBANKMENT I N AN AREA WITH MASSIVE GROUND I C E AT THE LOWER LIMIT OF ALPINE PERMAFROST

Cheng Kuo- tung and Tung Po- l iang , Research Ins t i tu te o f Glac io logy and Cryopedology, Academia S i n i c a , Lanchow, The P e o p l e ' s R e p u b l i c of China. Lo Hsueh-bo, Lanchow U n i v e r s i t y , Lanchow, The People ' s Republ ic o f China .

ABSTRACT

The Reshui experimental embankment i s s i t u a t e d i n a n area w i t h massive ground ice a t t h e lower limit o f t h e a l p i n e p e r m a f r o s t s i t u a t e d a t t h e s o u t h e r n f o o t o f t h e Ch i l i en Moun ta ins . Th i s pape r summar izes t h e data o b t a i n e d a f t e r a t h r e e - y e a r o b s e r v a t i o n p r o g r a m m e o n t h e e x p e r i m e n t a l embankment and ra i lway cons t ruc t ion p r a c t i c e i n t h e d i s c o n t i n u o u s p e r m a f r o s t r e g i o n o f t h e G r e a t e r K h i n g a n M o u n t a i n s . T h e i n f l u e n c e o f a number o f f ac to r s , i n c l u d i n g mater ia ls a n d s u r f a c e c o n d i t i o n s of t h e embankment, compression of t h e s o i l l a y e r s i n t h e b a s e c o u r s e , h e i g h t a n d exposure o f t he embankmen t , cons t ruc t ion s e a s o n s , water ( i n c l u d i n g . s u r f a c e a n d g roundwate r ) , and l ong- t e rm a i r t e m p e r a t u r e f l u c t u a t i o n s o n t h e p e r m a f r o s t t a b l e u n d e r t h e embankment are ana lyzed . Accord ing t o t h e s e a n a l y s e s , it a p p e a r s t h a t , u n d e r c e r t a i n c o n d i t i o n s it i s p o s s i b l e t o b u i l d embankments where massive ground ice o c c u r s a t t h e lower limit of t h e alpine p e r m a f r o s t based o n t h e p r i n c i p l e o f p r o t e c t i n g t h e p e r m a f r o s t . T h i s p a p e r p o i n t s o u t p r o b l e m s t o w h i c h a t t e n t i o n m u s t b e paid i n b u i l d i n g embankments i n t h i s sort o f t e r r a i n b a s e d o n t h e above p r i n c i p l e a n d p r o p o s e s f o r m u l a e s u i t a b l e for c a l c u l a t i n g t h e p o s i t i o n o f t h e p e r m a f r o s t table .

I n areas w i t h massive ground ice i n t h e d i s c o n t i n u o u s p e r m a f r o s t z o n e , t h e method of removing and r e p l a c i n g soil has a lways been adop ted f o r b u i l d i n g embank- m e n t s . T h i s m e t h o d c a u s e s d i f f i c u l t i e s i n c o n s t r u c t i o n a n d costs are h igh . O n t h e c o n t r a r y , i f t h e p r i n c i p l e of p r o t e c t i n g t h e p e r m a f r o s t w a s u s e d , it would be easy t o work and the expense would be lower. However, i f a d o p t i n g t h e p r i n c i p l e of p r o t e c t i n g t h e p e r m a f r o s t i n c o n s t r u c t i n g embankments i n r e g i o n s w h e r e the ground t e m p e r a t u r e i s n e a r O°C a n d t h e p e r m a f r o s t l a y e r i s t h i n , t h e q u e s t i o n t h a t has t o be answered i s whether it is p o s s i b l e t o e n s u r e t h e s t a b i l i t y of t h e embankment. I n o r d e r t o e x p l o r e t h e p o s s i b i l i t y of b u i l d i n g a n embankment i n a n area w i t h massive ground ice i n t h e d i s c o n t i n u o u s p e r m a f r o s t z o n e r e g i o n u s i n g t h e p x i n c i p l e of p r o t e c t i n g t h e p e r m a f r o s t , an e x p e r i - m e n t a l s t r u c t u r e was b u i l t i n R e s h u i ,

Ch ingha i P rov ince , i n Augus t , 1 9 7 1 . O b s e r v a t i o n s were c a r r i e d o u t t h e r e o v e r t h r e e c o n s e c u t i v e y e a r s t o l e a r n t h e r e l a t i o n s b e t w e e n c h a n g e s i n t h e p e r m a - frost t a b l e u n d e r t h e embankment and t h e v a r i o u s f a c t o r s w h i c h m i g h t i n f l u e n c e it.

GENERAL INTRODUCTION

Reshui i s l o c a t e d a t t h e s o u t h e r n f o o t o f t h e C h i l i e n M o u n t a i n s . The d i s - t r i b u t i o n o f p e r m a f r o s t t h e r e h a s v e r t i c a l z o n a t i o n , i . e . , f r o m a n e l e v a t i o n of 3 , 7 8 0 m u p w a r d s t h e r e i s a zone of c o n t i n u o u s p e r m a f r o s t , w h i l e f r o m 3 , 4 8 0 m t o 3 , 7 8 0 m a.s .1. t h e r e i s a t r a n s i t i o n a l z o n e w i t h s l o p e s i n f r o n t of t h e m o u n t a i n s a n d r a v i n e s a s w e l l a s v a l l e y s . The p e r m a f r o s t a n d s e a s o n a l l y f r o z e n g r o u n d a p p e a r as i s l a n d s or bands in te rwoven t o g e t h e r . B e l o w an e l e v a t i o n o f 3 , 4 8 0 m t h e r e are areas o f s e a s o n a l l y f r o z e n ground.

The expe r imen ta l s i t e i s i n t h e d i s - c o n t i n u o u s p e r m a f r o s t z o n e a t a n e l e v a t i o n o f 3 , 7 0 0 rn on a g e n t l e s l o p e . T h e r e i s a s p r i n g a t t h e u p p e r f o o t of t h e m o u n t a i n . Frost heaved pea t hummocks are s c a t t e r e d t h r o u g h o u t t h e s i te . According t o d a t a f r o m t h e l o c a l w e a t h e r s t a t i o n , t h e mean a n n u a l a i r t e m p e r a t u r e t h e r e w a s -3.7OC from 1 9 7 3 t o 1 9 1 4 . The ground begins t o t h a w i n t h e m i d d l e o f A p r i l , a n d r e a c h e s t h e maximum d e p t h i n t h e m i d d l e o f September . The depth o f thaw a t t h e e x p e r i m e n t a l s i t e is g e n e r a l l y 1.0-1.5 m. T h e a n n u a l p r e c i p i t a t i o n i s 500-600 mm, 90% of wh ich occu r s f rom June t o S e p t e m b e r . T h e s t r a t i g r a p h y a t t h e e x p e r i m e n t s i t e i s shown i n B o r e h o l e No.6 ( F i g u r e 1). From t h e s u r f a c e t o a d e p t h of 1 . 0 5 m a x e l a y e r s o f d e c a y e d v e g e t a t i o n , benea th wh ich l i e s a l a y e r of ground ice, a b o u t 5 m t h i c k . A b o r e h o l e , 1 0 0 m n o r t h of t h e e x p e r i m e n t a l embankment shows t h a t t h e t h i c k n e s s o f p e r m a f r o s t i s 3 0 rn and t h e mean annua l g round t empera tu re i s 0.5OC.

The experimental embankments were paved w i th c rushed s toney-c l ayey loam. T h e i r l a y o u t a n d b o r e h o l e l o c a t i o n s are shown i n F i g u r e 2 . The o r i e n t a t i o n of t h e embankments i s nor thwes t . Each has a

200

l e n g t h o f 1 0 m a n d h e i g h t s of 1, 2 and 3 m , r e s p e c t i v e l y . The t o p s a re 6 m wide and t h e s i d e s l o p e s a re I: 1.5. P e a t c o v e r e d berms were b u i l t o f c l a y e y loam o n b o t h s l o p e s o f t h e 3 m high embankment. They a re 1 m h igh and 2 m wide a t t h e t o p , Above t h e e m b a n k m e n t , a n i n t e r c e p t i n g d i k e w a s b u i l t a b o u t 3 - 5 m from i t s f o o t t o d i v e r t g r o u n d s u r f a c e w a t e r a n d s u p r a - p e r m a f r o s t water f r o m t h e u p p e r s l o p e .

T h e g r o u n d s u r f a c e t e m p e r a t u r e c a n be measured wi th a t h e r m o m e t e r , w h i l e t h e g r o u n d t e m p e r a t u r e i n t h e b o r e h o l e c a n b e measu red w i th a slow-changing thermometer . I t was v e r i f i e d b y d r i l l i n g t h a t t h e p o s i t i o n o f t h e p e r m a f r o s t t a b l e corres- ponds t o t h e O°C i s o t h e r m .

The experimental embankment was i n q u i t e g o o d c o n d i t i o n t h r e e y e a r s a f t e r c o n s t r u c t i o n . T h e p e r m a f r o s t t a b l e is a t d i f f e r e n t h e i g h t s i n t h e t h r e e embankments. The i n f l u e n c e of v a r i o u s f a c t o r s o n t h e p e r m a f r o s t t ab l e i n t h e embankments w i l l b e d i s c u s s e d i n r e l a t i o n t o t h e d a t a o b t a i n e d f r o m o b s e r v a t i o n s o n t h e e x p e r i m e n t a l s t r u c t u r e a n d o n t h e cmbank- m e n t i n t h e d i s c o n t i n u o u s p e r m a f r o s t z o n e i n n o r t h e a s t C h i n a .

FACTORS, WHICH HAVE INFLUENCE ON THE PERMaFROST TABLE UNDER AN EMBANKMENT

Embankment Material a n d S u r f a c e C o n d i t i o n s

Under cond i t ions o f one-d imens iona l h e a t f l o w t h e e x i s t e n c e a n d d e v e l o p m e n t o f t h e p e r m a f r o s t c a n b e e x p r e s s e d a s follows:

where Q- =

Q =

Q = 9

+

L a t e n t

h e a t r e l e a s e d i n w i n t e r h a l f of y e a r h e a t a b s o r b e d i n summer h a l f of y e a r a n n u a l h e a t f l o w f r o m i n t e r i o r of e a r t h a y e a r

h e a t i s t h e m a i n f a c t o r w h i c h c o n t r o l s t h e d e p t h of t h a w ( f r e e z i n g ) .

I t will b e more e f f e c t i v e when t h e y e a r l y s i t u a t i o n i s t a k e n i n t o c o n s i d e r - a t i o n . T h e r e f o r e , an approxirnate e s t i m a t i o n c a n be made:

where Q = l a t e n t h e a t o f t h a w i n g ( f r e e z i n g ) o f a v o l u m e t r i c u n i t of soil

The s u p e r s c r i p t "-" a n d t h e s u b s c r i p t "MI' d e n o t e t h e f r e e z i n g s t a t e , w h i l e t h e s u p e r s c r i p t "t" a n d t h e s u b s c r i p t "T"

d e n o t e t h e t h a w i n g s ta te .

hM = l a t e n t h e a t i n t h e s e a s o n a l l y f r o z e n l a y e r

h =

0

i n w h i c h -

A =

f ( t ) =

T =

R =

t h e r m a l c o n d u c t i v i t y of t h e s o i l t e m p e r a t u r e f u n c t i o n a t g round su r f ace t i m e when ground surface m a i n t a i n s a p o s i t i v e ( n e g a t i v e ) t e m p e r a t u r e t h a w i n g ( f r e e z i n g ) i n d e x of g r o u n d s u r f a c e

The v a r i a t i o n b e t w e e n F o r m u l a ( 2 ) and t h e c o m p u t e r r e s u l t i s l ess t h a n 5 % i n s e c t i o n s w i t h massive ground ice a t t h e lower limit o f a l p i n e p e r m a f r o s t .

T h e r e f o r e , w e c a n o b t a i n :

The r a t e a n d e x t e n t of t h e r ise i n t h e p e r m a f r o s t t a b l e i n t h e embankment depends on I Q - I - Q+ = Qg. The l a r g e r t h e

v a l u e of Q t h e q u i c k e r t h e r a t e and

e x t e n t i n t h e r ise of t h e p e r m a f r o s t t a b l e . g

Formula ( 3 ) shows t h a t , i n o r d e r t o make c o n d i t i o n s f a v o u r a b l e fo r t h e rise o f t h e p e r m a f r o s t t a b l e b e n e a t h t h e embankment, t h e s o i l w i t h a l a r g e r v a l u e o f Q a s w e l l a s of in,- s h o u l d

be c h o s e n f o r embankment m a t e r i a l . Because f i ne -g ra ined s o i l meets t h e s e c o n d i t i o n s w i t h r e g a r d t o the rma l con - d u c t i v i t y , i t s u s e as embankment material i s f a v o u r a b l e t o p r o t e c t i n g t h e p e r m a f r o s t and t o a r ise i n t h e p e r m a f r o s t table .

Compression of S o i l L a y e r s i n t h e Base Course o f t h e Embankment

The embankment l o a d a n d t r a f f i c w i l l c a u s e s e t t l e m e n t t o OCCUF fo r two r e a s o n s - compress ion of t h e embankment i tself a n d t h e b a s e c o u r s e . T h i s d i s c u s s i o n w i l l be conce rned ma in ly w i th compress ion of t h e b a s e c o u r s e .

O b s e r v a t i o n a t t h e R e s h u i e x p e r i m e n t a l embankment (Table 1) show t h a t t h e se t t lement of embankmen t s cons t ruc t ed i n summer i s c o n s i d e r a b l e . I t becomes weaker and weaker as time p a s s e s on ( F i g u r e 3 ) . The d e p t h of thaw was g r e a t e r d u r i n g

201

S e t t l e m e n t S e t t l e m e n t a f t e r c o m p l e t i o n Imm/year) No. of d u r i n g Total

Embankment C o n s t r u c t i o n S e t t l e m e n t (m) 1st y e a r 2nd y e a r 3 r d y e a r ( m m )

N o . 1 81.5 37.0-38.0 1 0 . 0 - 1 1 . 0 0- 5 .5 128.5-136.0

No. 2 115.5-124.5 58 .5-71 .5 15 .0-19 .0 5 .5 - 7 . 5 1 9 4 . 5 - 2 2 2 . 5

N o . 3 176 .0 88.5-91.5 31 .0-37 .5 15.5-23.5 314 .0-325.5 I I

Table 1 S e t t l e m e n t of E x p e r i m e n t a l Embankment

c o n s t r u c t i o n . T h e e n t i r e l a y e r of v e g e t a - t i o n a n d t h e u p p e r p a r t of t h e g r o u n d ice t h a w e d , r e s u l t i n g i n l a r g e s e t t l e m e n t u p t o 50% - 60% o f t h e t o t a l d u r i n g t h i s p e r i o d . I n t h e t h i r d y e a r a f t e r t h e embankment w a s c o n s t r u c t e d , t h e d e p t h of thaw dec reased and t he t hawing and com- p r e s s i o n of t h e v e g e t a t i o n l a y e r g r a d u a l l y s t a b i l i z e d . T h e a n n u a l s e t t l e m e n t was g e n e r a l l y less t h a n 3 c m .

The e x t e n t of s e t t l e m e n t d e p e n d s o n t h e d e p t h of t h a w , l i t h o l o g i c a l c h a r a c t e r s of t h e s o i l i n t h e b a s e c o u r s e , water c o n t e n t , embankment h e i g h t a n d materials. G e n e r a l l y s p e a k i n g , t h e g r e a t e r t h e d e p t h of t h a w , t h e h i g h e r t h e water c o n t e n t i n t h e s o i l l a y e r s at t h e b a s e c o u r s e , a n d t h e g r e a t e r t h e s e t t l e m e n t o f t h e embankment w i l l be. Pea t and o the r decomposed v e g e t a t i o n h a s e s p e c i a l l y h i g h c o m p r e s s i o n c a p a c i t y . When a l l o t h e r c o n d i t i o n s a re similar, t h e h i g h e r t h e e m b a n k m e n t , t h e more s e r i o u s t h e s e t t l e m e n t ( F i g u r e 4).

G e n e r a l l y t h e u p p e r s t r a t a of a n ice r i c h s e c t i o n i s composed of p e a t a n d v e g e t a t i o n , w h i c h w i l l b e e a s i l y s a t u r a t e d a f t e r thawing. While under compression, t h e water c o n t e n t d e c r e a s e s a n d t h e d r y vo lume we igh t i nc reases . The t he rma l c o n d u c t i v i t y o f t h e s o i l i n c r e a s e s i n r e s p o n s e t o a n i n c r e a s e i n i t s water c o n t e n t a n d t h e d r y v o l u m e w e i g h t . A r e d u c t i o n i n water c o n t e n t a f t e r t h e s o i l l a y e r s a re compressed is c o n d u c i v e t o a d e c r e a s e i n t h e r m a l c o n d u c t i v i t y a n d a n i n c r e a s e i n t h e d r y v o l u m e w e i g h t w i l l a g a i n c a u s e a n i n c r e a s e i n t h e r m a l c o n d u c t i v i t y . T h e r e f o r e , w h e t h e r t h e h e a t c o n d u c t i v i t y c a n f i n a l l y b e i n c r e a s e d or r e d u c e d a f t e r t h e s o i l l a y e r s a re com- p r e s s e d d e p e n d s o n s p e c i f i c c o n d i t i o n s . R e s u l t s of i n v e s t i g a t i o n s a t Reshui show t h a t a f t e r t h e v e g e t a t i o n l a y e r b e n e a t h

t h e embankment was compressed, i t s t h e r m a l c o n d u c t i v i t y i n c r e a s e d s l i g h t l y .

T h e t h e r m a l c o n d u c t i v i t y X- o f t h e f r e e z i n g s o i l and A+ o f t h e t h a w i n g s o i l a l so i n c r e a s e i n r e s p o n s e t o a rise of wa te r con ten t and d ry vo lume we igh t . The r a t e s of X- and A' which r ise t o g e t h e r w i t h a n i n c r e a s e i n d r y v o l u m e w e i g h t , a x e similar, w h i l e t h e r a t e of i n c r e a s e i n water c o n t e n t f o r A - i s more r a p i d t h a n t h a t of X+. T h e r e f o r e , a f t e r c o m p r e s s i o n of the s o i l l a y e r s , t h e d i f f e r e n c e b e t w e e n A " and A t w i l l d e c r e a s e , w h i c h is n o t c o n d u c i v e t o p r o t e c t i n g t h e p e r m a f r o s t .

I n s o i l w i t h h i g h water c o n t e n t , t h e m a i n f a c t o r , d e t e r m i n i n g t h e d e p t h of thaw, i s t h e l a t e n t h e a t i n a v o l u m e t r i c u n i t of s o i l . A d e c r e a s e i n water c o n t e n t a f t e r compress ion of t h e so i l l a y e r s w i l l c e r t a i n l y l e a d t o a d e c r e a s e o f l a t e n t h e a t i n a v o l u m e t r i c u n i t o f so i l . Com- p a r e d w i t h t h e o r i g i n a l c o n d i t i o n s , it c a n , of c o u r s e , r e s u l t i n a n i n c r e a s e i n t h e d e p t h of t h a w . I n t h e mean time, t h e d e c r e a s e i n t h i c k n e s s of t h e soil l a y e r s a t t h e b a s e c o u r s e , d u e t o compress ion , w i l l b e e q u i v a l e n t t o t h e i n c r e a s e i n d e p t h of thaw.

I t s h o u l d a l so b e p o i n t e d o u t t h a t t h e c o e f f i c i e n t of p e r m e a b i l i t y w i l l d e c r e a s e a f t e r c o m p r e s s i o n of t h e so i l L a y e r s a t t h e base c o u r s e . When water p e r m e a t e s i n t o t h e b a s e c o u r s e , t h e d e c r e a s e i n t h e c o e f f i c i e n t of perme- a b i l i t y w i l l h e l p t o r e d u c e t h e rate of c o n v e c t i v e h e a t e x c h a n g e .

Height and Exposure of t h e Embankment

I t is known from t h e a b o v e d i s c u s s i o n t h a t t h e c o m p r e s s i o n of soil l a y e r s a t t h e b a s e c o u r s e a f t e r c o n s t r u c t i o n of t h e

202

embankment may p o s s i b l y c a u s e a n i n c r e a s e

d F - d of t h e embankment material are i n t h e d p th o f thaw. The va lues Q , x and

also d i f f e r e n t f r o m t h o s e of t h e s o i l l aye r s i n t he s easona l ly t hawed g round . The s u r f a c e h e a t e x c h a n g e c o n d i t i o n s w i l l also c h a n g e a f t e r c o n s t r u c t i o n o f t h e embankment. A l l t h e s e may c a u s e t h e p e r m a f r o s t t a b l e t o d e p r e s s u n d e r c e r t a i n c o n d i t i o n s . However, t h e f a c t i s t h a t t h e e x i s t e n c e of t h e embankment can deve lop the rma l r e s i s t ance wh ich w i l l be a f a c t o r conducive t o a r i s i n g o f t h e p e r m a f r o s t t a b l e . When t h e embankment is very low, t h e e f f e c t of d i s a d v a n t a g e o u s f a c t o r s , w h i c h c a n c a u s e t h e p e r m a f r o s t t a b l e t o d e p r e s s , a l w a y s e x c e e d s t h e e f f e c t o f t h e a d v a n t a g e o u s f a c t o r s t h a t make t h e perma- f r o s t t a b l e rise. T h u s , t h e f i n a l r e s u l t i s t h a t t h e p e r m a f r o s t t a b l e is depressed . Wi th the g radual ra i s ing of the embankment , t h e e f f e c t o f t h e a d v a n t a g e o u s f a c t o r s w i l l g r a d u a l l y i n c r e a s e . Once t h i s e f f e c t i n c r e a s e s t o o r e x c e e d s t h e e f f e c t of t h e d i s a d v a n t a g e o u s f a c t o r s , t h e p e r m a f r o s t t a b l e w i l l become s t a t i o n a r y ox r i s e i n t h e embankment. I n t h i s way, u n d e r c e r t a i n c o n d i t i o n s , t h e r e is an optimum h e i g h t of t h e embankment, such t h a t when i t s a c t u a l h e i g h t i s g r e a t e r t h a n t h i s h e i g h t , t h e p e r m a f r o s t t a b l e w i l l r ise, and, when t h e a c t u a l h e i g h t o f t h e embankment i s lower, t h e p e r m a f r o s t t a b l e w i l l d rop . This h e i g h t i s c a l l e d t h e minimum embankment h e i g h t , w h i c h c a u s e s t h e o r i g i n a l perma- f r o s t t a b l e t o b e s t a t i o n a r y . I t i s e x p r e s s e d a s Nmin, and can be ca lcu la ted

from t h e f o l l o w i n g f o r m u l a :

2 1 Z X I T ' Ql + 1 3 Q QI

F - - h + S ( 4 )

where All Q1 = t he rma l conduc t iv i ty and l a t e n t h e a t i n a vo lumet r i c u n i t of embankment m a t e r i a l

h z Q 2 = t h e m a l c o n d u c t i v i t y a n d l a t e n t h e a t i n a vo lumet r i c u n i t of t h e b a s e c o u r s e a f t e r c o m p r e s s i o n

h = n a t u r a l p e r m a f r o s t t a b l e F = a v e r a g e p o s i t i v e t e m p e r a t u r e

of t h e embankment t op s u r f a c e i n t h e t h a w i n g p e r i o d

T I = l eng th o f time f o r p o s i t i v e tempera ture of t h e embankment s u r f a c e

S = e x t e n t o f s e t t l e m e n t

When l a c k o f d a t a , ['::I - F] can be

r ep laced approx ima te ly by t h e maximum dep th of thaw o f t h e embankment m a t e r i a l (he ) unde r na tu ra l . cond i t ions , i .e . ,

2X.T ' hz = Q1 I F

Formula ( 4 ) i s s u i t a b l e f o r t h e minimum h e i g h t o f embankments i n t h e ice r i c h s e c t i o n s n e a r t h e l o w e r l i m i t o f t h e a l p i n e p e r m a f r o s t . A c t u a l l y , Hmin i s t h e f u n c t i o n o f t h e mean annual ground temper- a t u r e . When o t h e r c o n d i t i o n s a r e s imilar , t h e l o w e r t h e mean annual ground temper- a t u r e , t h e s m a l l e r t h e minimum h e i g h t of t h e embankment w i l l be .

When it is necessa ry t o c a u s e t h e p e r m a f r o s t t a b l e i n t h e embankment t o r ise t o t h e g round su r f ace , t he re a l so e x i s t s a c r i t i c a l h e i g h t . When t h e a c t u a l h e i g h t o f a n embankment is equa l t o o r g r e a t e r t h a n t h i s c r i t i c a l h e i g h t , t h e p e r m a f r o s t t a b l e w i l l r ise to t h e ground sur face ox e n t e r t h e embankment. T h i s c r i t i c a l h e i g h t c a n b e shown a s :

BC 2b + Hctgcl

I H 0 1 2 3 4 5

(m )

m 1 . 0 0 1-01 1 . 0 2 1.04 1.05 1-07

vt Ql 0 = mh 2 ( 5 )

Tab le 2 Value m of embankments f o r d i f f e r e n t h e i g h t s 2b = 6x11, ctgcl = 5

2

m

0

N

1-

-

rn 0

0

+

M

rl

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0

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0

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d

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t

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mum

0 0

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0

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d

..

e e

d

0

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n

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d

0

cv d

a

0

w 0

+

Ln m

+ 0

M

4

a

+

N

m

4 -

w

IC

0

W e

N

W

N

m

0

m

N

0

In

d

N

-r

rl

m

m

4

M

w

cv

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d

0

N

d

0

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0

W 0

0

+

W

N

0

+

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m

N

N

0

0

+ 0

-I-

w a

d

0 a

N

r-. W

m

0 0

N

m

m

d

0

N

4

0

Ln

0

0

m

0

Ln m

d

Ln r- N

m

N

0

I

0

m

W

m

"_ m

0

N

0

0

0

Tr

m

m

N

I

m

0

0

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0

N

4

Ln 0

rl

Ln d

4

m 0

4

20

4

M

0

I

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d

I

w

0

I

e

0

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r-

d

I

m

d

1

w 4

d a,

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c, c a,O

0

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mm

(

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me

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a

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c,

d

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h

F: F: 3

m

d

r- a 3

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r: c 3

v1

d

rl

n

3

m Ll : 0

04 x w

w u

d

ar 5 h

r: m v1

a h

E

m

[II

a h

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(d

m

d

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3

n

r- rl

n

1

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w c,

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00

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m

da

rdc E

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ma

r

im

00

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z 0

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m

V

fl W

ul V

do 0

Ln V

O\O

W

Ln V

0

m

V

m

0

I Ln

0

m

0

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W

0

0

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mo

1

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0

m

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m

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0

m

d rl

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5

c co rd

205

0

4

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I

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0

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ul

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m

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03

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ul

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M

m -

m

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0

I

co N

$4 5

w

uo

m

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I

a, L4 2 0 a x W

w 2

m

0

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r- I

d

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0

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a

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0

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m

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20

6

d

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+

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0

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W

0

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c! a,

0

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I

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4

0

+ W

0

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a

0

a

c CI

b

a

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0

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m

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Ln

m

rc, .. 00

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0

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0 t

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0

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d

+ c h r: 1 m

h

r: E: I

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h

c, F: 7

m

m h

c m

m

a h

2 rn

a h (d

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E: F: 5

rn

0

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z 0

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0

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m

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7 I

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n

0

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3

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n

0

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3 9

3

v . 3

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n 9

3

f

D

3

D 0

3

0

m

0

W

m

0

d II

0

n

Y

3

m

e

N

N

W

* m

w

m

e

m

m

Ln

03

N

-

0

W

m

0

m

m

0

I

Ln

0

I

I-

O I

e

0

m

0

I

4

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-

e

0

I

M

0

I

rl

4

W

0

I

m

0

I

-

0

-4 I

e

m

a I

rl

I

cv 0

I 4

I

rl

N

0

I N

I

0

0

I

0

0

rl

W I

0

I

I"

W I

4

0

I

0

0

l-.

w I

M

0

I

rl

0

I

-I

0

I

I-

W I

Ln

m I

0

I

0

N

0

I (u

0

m

N

N

m

rl

20

9

rtl 0

W

rl

0

I-

I"

0

+ 0

r. W

N

Ln 03

N

01

Tv

Ln

r-

N

LC

N

4J ro

E:o

W

0

0

+ a

0

n

L4

m

W

0

m

W

m

m

a

m

W 0

r- N

N

Ln 0

?I

Ln 0

4

210

where H =

2b =

a = F =

m =

When 2b

h e i g h t of embankment w i d t h of t o p of embankment s l o p e a n g l e of embankment

f u n c t i o n o f embankment s u r f a c e t e m p e r a t u r e

" + [2b+;ctaal2 -- i n f l u e n c e coeff i d i e n t w h i k h i s related t o t h e g e o m e t r i c a l s h a p e s of t h e embankments

= 6 m , t h e s l o p e s are 1:1.5, t h e v a l u e rn o f d i f f e r e n t h e i g h t s i s shown i n Table 2 .

When t h e h e i g h t of t h e embankment m a t e r i a l e x c e e d s t h e minimum h e i g h t of t h e embankment , required t o m a i n t a i n t h e o r i g i n a l e l e v a t i o n of t h e p e r m a f r o s t t ab l e , a r ise o f t h e p e r m a f r o s t t a b l e i n t h e embankment w i l l o c c u r . G e n e r a l l y s p e a k i n g , t h e h i g h e r t h e embankment, t h e g r e a t e r t h e rise o f t h e p e r m a f r o s t t a b l e . Data from the Reshui exper imenta l embankment (Table 3 ) h a v e p r o v e d t h i s .

However, a s t h e embankment c o n t i n u e s t o r ise and i t s h e i g h t r e a c h e s a c e r t a i n v a l u e , t h e p e r m a f r o s t t a b l e i n t h e embankment w i l l b e g i n t o d r o p a g a i n . Data from t h e d i s c o n - t i n u o u s p e r m a f r o s t z o n e r e g i o n s i n t h e Greater K h i n g a n M o u n t a i n s i n n o r t h e a s t C h i n a h a v e p r o v e d t h i s ( T a b l e 4).

U s u a l l y , a h i g h embankment imposes a h i g h l o a d w h i c h a l w a y s c a u s e s s e t t l e m e n t a t t h e base c o u x s e t o a c o n s i d e r a b l e e x t e n t forming a d i s h - s h a p e d d e p r e s s i o n . When permeable coarse sand i s used as f i l l f o r t h e lower p a r t of t h e embankment, it a l w a y s c a u s e s d i s h - s h a p e d d e p r e s s i o n s w i t h s t a g n a n t or permeat ing water, w h i c h a d v e r s e l y a f f ec t s t h e d e s c e n t of t h e p e r m a f r o s t table . There- f o r e , it i s p r e f e r a b l e t o u s e c l a y e y loam as f i l l f o r t h e Lower p a r t of a h i g h embankment.

When ' t h e embankment i s n o t SO h i g h , t h e t o p s u r f a c e w i l l be t h e m a i n h e a t e x c h a n g e s u r f a c e . W i t h i n c r e a s i n g embank- m e n t h e i g h t , . . t h e area o f t h e s l o p e s u r f a c e w i l l i n c r e a s e , too. For a high embankment, t h e s l o p e i s t h e m a i n s u r f a c e of h e a t exchange. A s t h e s l o p e h a s d i f f e r e n t e x p o s u r e s a n d g r a d i e n t s , t h e i n t e n s i t y a n d p e r i o d of solar r a d i a t i o n are d i f f e r e n t too. Thus, it has i t s own s p e c i a l c h a r a c t e r i s t i c s i n r a d i a t i o n a n d h e a t b a l a n c e . As a r e s u l t , t h e t e m p e r a t u r e of d i f f e r e n t s l o p e s , g r o u n d t e m p e r a t u r e below t h e s l o p e a n d level o f t h e p e r m a f r o s t t ab le are a l l d i f f e r e n t .

The l a t i t u d e o f Reshui i s 3 7 O 4 0 ' ~ and t h e o r i e n t a t i o n of t h e e x p e r i m e n t a l embankment i s s o u t h e a s t . T h u s , t h e t e m p e r a t u r e d i f f e r e n c e b e t w e e n t h e t o p s u r f a c e a n d t h e

s l o p e s u r f a c e o n b o t h s i d e s is n o t l a r g e . T h e s u r f a c e t e m p e r a t u r e of t h e s o u t h w e s t s l o p e i s h i g h e r t h a n t h a t o f t h e n o r t h e a s t s lope . The d i f f e rence be tween t hem depends o n t h e v a r i o u s l i t h o l o g i c a l c h a r a c t e r i s t i c s (Table 5 ) .

T h e d i f f e r e n c e i n g r o u n d t e m p e r a t u r e a t t h e 3 rn d e p t h b e n e a t h t h e s l o p e s w i t h d i f f e r e n t e x p o s u r e s i s 0 .5 - 0.6OC. The d i f f e r e n c e i n t h e p e r m a f r o s t t a b l e d e p t h i s 0.2-0.7 m.

T h e l a t i t u d e of t h e r a i l w a y s e c t i o n f r o m J i a g e d a q i t o X i n t i a n i n n o r t h e a s t China i s 50°24'N, 51OlO'W. Because of t h e h i g h e r l a t i t u d e , t h e d i f f e r e n c e c a u s e d by exposure i s c o m p a r a t i v e l y l a r g e , e s p e c i a l l y when t h e r o u t e d i r e c t i o n i s east-west. The phenomenon o f t e n o c c u r s w h e r e t h e p e r m a f r o s t t a b l e rises o n t h e n o r t h e r n s i d e a n d d r o p s o n t h e s o u t h e r n s i d e ( T a b l e 7 ) .

A f t e r c o n s t r u c t i o n of t h e embankment, t h e a r e a of h e a t e x c h a n g e i n c r e a s e s , compared to t h e o r i g i n a l g r o u n d s u r f a c e , s u c h t h a t a b s o r p t i o n of h e a t i n c r e a s e s i n summer a n d i n h e a t loss i n c r e a s e s i n w in te r . Thus , if t h e f r e e z i n g i n d e x of t h e embankment s u r f a c e ( i n c l u d i n g t h e t o p s u r f a c e a n d t h e t w o s l o p e s ) e x c e e d s t h e t h a w i n g i n d e x , t h e i n c r e a s e o f t h i s h e a t e x c h a n g e s u r f a c e w i l l f a v o u r a r ise i n t h e p e r m a f r o s t t a b l e i n t h e e m b a n k m e n t , a n d v i c e versa. W e c a n c o n t i n u e a n a p p r o x i m a t e measur ing of t h e mean a n n u a l t e m p e r a t u r e a t t h e g r o u n d s u r f a c e i n a c c o r d a n c e w i t h t h e weighted means of t h e area a n d d e t e r m i n e w h e t h e r t h e f r e e z i n g i n d e x of t h e embank- m e n t s u r f a c e i s l a r g e r t h a n i t s thawing index . Suppose t he w id th a t t h e t o p o f t h e embankment i s 2b, t h e slope a n g l e i s a, t h e embankment h e i g h t i s H I t h e mean a n n u a l t e m p e r a t u r e a t t h e t o p of t h e embankment i s F1 a n d t h e mean a n n u a l t e m p e r a t u r e o n b o t h s l o p e s u r f a c e s are F2 and F3 r e s p e c -

t i v e l y , t h e n t h e mean a n n u a l t e m p e r a t u r e F on t h e s u r f a c e of t h e embankment can be e x p r e s s e d b y t h e w e i q h t e d m e a n s of t h e area F ~ ,

suppose

R =

2bF1 + HcscaF2 + HcscaF3 2 b -k 2Hcsca

6F + Hcsca F2 + F3 1.

b + Hcsccl

+ HCSCcl, Hcsccl t h e above f o r m u l a c a n

be r e w r i t t e n as:

211

c o e f f i c i e n t v a l u e m w i l l a l s o i n c r e a s e . However, when t h e s e t t l e m e n t i s no t t oo g r e a t , t h e v a l u e m w i l l be very smal l .

When the one-dimensional formula i s used i n s t ead of the two-dimensional formula (when thawing i s c o n t i n u i n g i n t h e embankment) , t h e e x p r e s s i o n o f r e l a t i v e p r e c i s i o n c a n b e w r i t t e n as fo l lows:

When H changes from 0 , R will change from 0 t o 1. Consequent ly , wi th a raise i n h e i g h t o f t h e embankment, t h e s u r f a c e tempera ture o f bo th s lopes w i l l i n c r e a s e . I ts i n f l u e n c e s w i l l i n c r e a s e , too.

When F>O, it means t h a t t h e f r e e z i n g index o f t he embankment s u r f a c e i s Less than i t s thawing index. The i n c r e a s e o f t he hea t exchange su r f ace by t h i s time w i l l b e u n f a v o u r a b l e t o p r o t e c t i n g t h e perma- f r o s t . If F i O , t h e i n c r e a s e o f t h e h e a t exchange surface w i l l be f avourab le t o p ro tec t ion o f t he pe rmaf ros t .

Here, w e a r e g o i n g t o d i s c u s s a g a i n how geometr ica l shapes of embankments i n f l u e n c e t h e p e r m a f r o s t t a b l e . When t h e thawing is still p r o g r e s s i n g i n t h e embankment, the depth o f thaw (h) under t h e embankment can be expressed as fo l lows:

I t has been ment ioned before tha t , unde r t he cond i t ions a t the Reshu i expe r i - mental embankment, one can consider approx ima te ly t ha t , ( F 2 + F ) / 2 = F1. Thus Formula ( 7 ) c an be r ewr i t t en as fo l lows:

3

where mt is t h e d e p t h of thaw i n the one-d imens iona l condi t ion ,

H m = which only r e l a t e s t o t h e d i m e n s i o n o f t h e embankment c ros s - sec t ion , and m c a n a l s o b e c a l l e d t h e c o e f f i c i e n t 01’ i n f l u e n c e o f t h e geometr ical shape of t h e embankments on t h e depth of thaw.

’ + (Zb+Hctga ) ’ i s t h e c o e f f i c i e n t

The t o p w i d t h 2b and t he s lope ang le s o f t h e embankment are r e l a t i v e l y s t a b l e . When 2b = 6 m and t h e s l o p e s are 1:1.5, t h e v a l u e m c a n b e l i s t e d i n T a b l e 2 . From Table 2 , one can see t h a t when the embankment h e i g h t i n c r e a s e s , t h e i n f l u e n c e

When S<5% i s r e q u i r e d , m should be 1 . 0 5 , and then, one can see t h a t t h e h e i g h t of t h e embankment i s 4 m accord ing t o T a b l e 2 . T h e r e f o r e , i f t h e d e p t h o f thaw i n a n embankment wi th a he igh t o f less than 4 m is worked o u t w i t h a one- d i m e n s i o n a l f o r m u l a , t h e r e l a t i v e p r e c i s i o n w i l l be less than 5%.

Cons t ruc t ion Seasons

Because o f t he i n f luence o f t he hea t s t o r e d i n t h e embankment, t h e o r i g i n a l p e r m a f r o s t t a b l e i n a n embankment c o n s t r u c t e d i n summer w i l l u sua l ly d rop . The problems in engineer ing, about which peop le a r e conce rned a r e : whe the r t he s to red hea t can d i spe r se and a t what r a t e . According to the one-d imens iona l formula , w e a r e s t u d y i n g t h e e f f e c t o f t h e h e a t s t o r e d by summer c o n s t r u c t i o n .

Suppose the depth of thaw i s H n-1’ i n t h e n - 1 y e a r a f t e r c o n s t r u c t i o n o f t h e embankment; it w i l l be Hn i n t h e n year .

According t o da ta ob ta ined f rom the Reshui experimental embankment, the ground t e m p e r a t u r e a t t h e d e p t h o f z e r o a n n u a l ampl i tude 2 m b e n e a t h t h e embankment i s not in f luenced by the cons t ruc t ion . Thus , it can be assumed tha t the g round temper- a t u r e ( U T ) a t t h e d e p t h of zero annual ampl i tude (Hr ) i s a c o n s t a n t .

For an embankment w i t h a thawed l a y e r i n t h e n - t h y e a r a f t e r c o n s t r u c t i o n , t h e hea t ga ins and l o s ses t h rough t he who le year can be w r i t t e n as fo l lows :

where g = hea t abso rbed due t o ex tens ion of t h e thawed l a y e r (when €II1 HI1-l) , o r h e a t r e l e a s e d d u e t o c o n s t r u c t i o n of t h e thawed l a y e r (when Hn H n - l ) , i n t h e n - t h y e a r , o b v i o u s l y

= IHn - Hn - l )Q

212

g = h e a t f l o w from the t hawed l a y e r t o t h e u n d e r l y i n g f r o z e n s t r a t a i n t h e n - t h y e a r .

-

i n w h i c h , X; = h e a t c o n d u c t i v i t y o f t h e u n d e r l y i n g f r o z e n s t r a t a

T = t i m e (a y e a r )

x ;T R = -1U I = v a l u e t h a t c a n c a u s e Hn OH1 1

t o r i se d u e t o h e a t f l o w f r o m t h e t h a w e d l a y e r t o u n d e r l y i n g f r o z e n s t r a t a

qn = a l g e b r a i c q u a n t i t y o f h e a t t h a t t h e t h a w e d l a y e r receives f r o m o u t s i d e t h r o u g h t h e g r o u n d s u r f a c e d u r i n g t h e t h a w p e r i o d a n d t h e h e a t t h a t t h e t h a w e d l a y e r releases t h r o u g h t h e g r o u n d s u r f a c e d u r i n g t h e f r e e z i n g p e r i o d i n t h e n - t h y e a r

- PQ "

2Hn

i n w h i c h T I , T I ' = c o n t i n u a l p e r i o d of n e g a t i v e a n d p o s i t i v e t e m p e r a t u r e s of t h e g r o u n d s u r f a c e r e s p e c t i v e l y

f - , f + - mean s u r f a c e t e m p e r - a t u r e i n w i n t e r a n d summer r e s p e c t i v e l y

I n t h i s way, ( H n - Hn-l) = -Q + - (11) P

2Hn

T h i s f o r m u l a i s g o i n g t o be d i s c u s s e d as f o l l o w s :

1) r>o

(a) When H <--, qn> I y-1 . Thus, p 0 , P n 2R

and Hn>H -1, i . e . , t h e d e p t h of thaw

i n c r e a s e s a n d t h e t h a w e d l a y e r i s e x t e n d e d . W i t h a n i n c r e a s e o f I1 n , qn = P/2Hn.Q will d e c r e a s e . However, when H i n c r e a s e s t o a

n

n

v a l u e e q u a l t o p/2, q = 0 and t he t hawed l a y e r will. be i n a s ta te of b a l a n c e .

t h a w d i m i n i s h e s , t h e t h a w e d L a y e r w i l l c o n t r a c t . W i t h a d e c r e a s e o f H n ' qn - p/2Hn.Q w i l l i n c r e a s e . When Hn d i m i n i s h e s

t o a v a l u e e q u a l t o p/2, g = 0 a n d t h e t h a w e d l a y e r w i l l b e i n a s ta te of b a l a n c e .

-

Thus, when p>O(hT>hM) , t h e t h a w e d

l a y e r w i l l n e v e r d i s a p p e a r , a n d t h e d e p t h of thaw w i l l r emain H = p/2R. From t h e a b o v e d i s c u s s i o n we c a n see t h a t t h e i n i t i a l d e p t h of thaw caused by cons t ruc- t i o n i n summer w i l l d i r e c t l y i n f l u e n c e t h e t e n d e n c y i n t h e c h a n g e of t h e t h a w e d l a y e r .

I n t h e a b o v e d i s c u s s i o n , Ur i s p r e -

sumed t o b e u n c h a n g e a b l e . T h i s i s o n l y cor rec t , when t h e h e i g h t of t h e embankment c o n s t r u c t e d i n summer i s n o t g r e a t , t h e i n i t i a l d e p t h o f t h a w Bo i s n o t laxge, and

t h e e x i s t e n c e of t h e t h a w e d l a y e r i s s h o r t . When t h e e x i s t e n c e of the thawed band i s p r o l o n g e d , t h e u p p e r s u r f a c e o f t h e u n d e r - l y i n g f r o z e n s t r a t a w i l l c o n t i n u o u s l y h a v e a p o s i t i v e t e m p e r a t u r e , a n d t h e lower s u r f a c e w i l l b e i n f l u e n c e d b y t h e h e a t f l o w from t h e i n t e r i o r of t h e e a r t h . T h e r e f o r e , t h e mean annual g round t e m e r a t u r e w i l l i n c r e a s e , r e s u l t i n g i n I q - p d i m i n i s h i n g , c a u s i n g H t o i n c r e a s e a n d t h e h e a t

d i s p e r s i n g t o w a r d s b o t h s i d e s w i l l a l so i n c r e a s e . T h e r e s u l t w i l l be t h a t two c o n d i t i o n s a p p e a r : o n e is t h a t t h e perma- f r o s t t h a w s c o m p l e t e l y , a n d t h e o t h e r i s t h a t a s t a b l e t h a w b a s i n f o r m s .

n

2 ) P<O

Now t h a t qn i s smaller t h a n 0 , - q is also smaller t h a n 0 , r e s u l t i n g i n Hn<HnW1; i . e . , t h e d e p t h o f t h a w d i m i n i s h e s

a n d t h e t h a w e d l a y e r w i l l c o n t r a c t . W i t h

a d e c r e a s e o f H n , / y n \ = lPlQ w i l l i n c r e a s e .

T h e r e s u l t is t h a t Hn d i m i n i s h e s more q u i c k l y , f i n a l l y b r i n g i n g a b o u t t h e d i s - a p p e a r a n c e of t h e t h a w e d l a y e r .

2Hn

The number of y e a r ( n ) when t h e t h a w e d l a y e r d i s a p p e a r s c a n b e o b t a i n e d b y t h e f o l l o w i n g f o r i n u l a :

n = - 1

where (A) i n d i c a t e s t h e i n t e g e r p a r t of A

213

Ho - -

i n which H =

h =

s =

The drop caused by t h e

H+h+s i n d i c a t e s t h e i n i t i a l depth of thaw

he ight o f the embankment

na tu ra l pe rmaf ros t t ab l e

the d rop i n t he pe rmaf ros t t ab le caused by construct ion i n summer

s of the permafros t t ab le c o n s t r u c t i o n i n s m e r i s

r e l a t e d t o the he igh t o f t he embankment., months of cons t ruc t ion , du ra t ion of t h e cons t ruc t ion per iod , ice content and thermal conduct ivi ty of t h e s o i l n e a r t h e permafrost table . According to the observed da ta , the ice content and thermal conduct iv i ty o f the so i l near the perma- f r o s t t a b l e a r e t h e main f a c t o r s . F o r example, according to observations on t h e cons t ruc t ion of the experimental embankment a t t h e Huchung Branch Line, where there was a th i ck pea t l aye r w i th h igh i ce con ten t i n t he s easona l ly thawed l a y e r , t h e maximum depth of thaw beneath the embankment cons t ruc ted in summer approached that of t h e n a t u r a l p e r m a f r o s t t a b l e , i . e . , S=O (Table 8). As for the exper imenta l embankment a t Reshui, it was a l so cons t ruc ted i n summer. Gene ra l ly , i n o n e or two months a f t e r cons t ruc t ion , dep th o f thaw w i l l be c lose t o t he na tu ra l pe rmaf ros t t ab l e . Therefore , to measure the th ickness of t h e p e a t l a y e r and the h igh ice con ten t , Bo = h+h can be adopted.

I f t h e thawed l a y e r i s r e q u i r e d t o disappear i n the n - th year a f t e r t h e cons t ruc t ion , then

.:-hi

2Rhm-P '

H ,< ;$ 4- n (2Rh rn -hT+G) 2

I n t h i s way, i n o r d e r t o make t h e thawed layer disappear in n yea r , t he re i s an optimum he igh t Hn €or the embankment. When t h e a c t u a l h e i g h t of an embankment is grea ter than H n , t h e thawed l a y e r w i l l not disappear within n yea r s .

Hn = hM + n($+2 $-hT) - h - s ( 1 2 )

General ly , the higher and t h e f i n e r gra ined the embankment ma te r i a l , t he l onge r the thawed l a y e r w i l l exis t . Data f rom the experimental embankment a t Reshui show t h a t

t h e thawed l a y e r i n t h e embankment lower than 3 m disappeared i n t h e f i r s t and second winters. Observation a t t h e Huchung Branch Line experimental embankment a l s o shows t h a t t h e 3-5 m high embankments axe genera l ly f rozen th roughout in the second or th i rd win ter . If t h e embankment constructed i n summer is too h igh , the thawed l aye r w i l l l a s t longer. Therefore, the permafros t t ab le w i l l drop considerably. A 13 m high embankment cons t ruc t ed i n summer on the r a i lway s ec t ion from Jiagedagi to Xint ian can serve as an example, where the permafrost table dropped 1 . 0 - 2 .3 m.

Embankments cons t ruc ted in summer should no t be bu i l t wi th insu la ted berms b e c a u s e h e a t s t o r e d i n t h e f i l l w i l l . p ro long the ex is tence of t h e thawed l a y e r . Thus, it i s p r e f e r a b l e t o i n s t a l l t h e in su la t ed berms a f t e r t he d i sappea rance o f t he thawed l a y e r .

As mentioned above, embankments cons t ruc t ed i n summer w i l l always cause the o r ig ina l pe rmaf ros t t ab l e t o d rop and the ground ice t o melt. Observation on Reshui Embankment No. 3 a l s o show t h a t , t h ree yea r s a f t e r cons t ruc t ion , be tween the dep ths of 2 . 5 and 4 m from the t op , t h e r e was still a l a y e r of warm permafrost with temperatures approaching zero. This was not favourable to the s t a b i l i t y of t h e embankment. If cons t ruc t ion had been car r ied ou t in win ter , the working cond i t ions would have been very d i f f icu l t . The re fo re i n o rde r t o f i nd a s t r u c t u r a l type of embankment s u i t a b l e f o r c o n s t r u c t i o n i n i c e - r i c h s e c t i o n s n e a r t h e lower limit of permafrost, an experiment with a v e n t i l a t e d embankment was c a r r i e d o u t i n the Reshui Region.

Construction of a v e n t i l a t e d embankment began i n May 1 9 7 3 and was completed i n the l a s t t e n d a y s of Ju ly . The base course of t h e embankments c o n s i s t s of a 0 . 5 m t h i c k l a y e r of clayey loam on t h e natural vegetated surface covered with 0 . 3 m diameter sandstone fragments. Above was a g rave l l aye r 0 .15 m t h i ck . The v e n t i l a t e d embankment i s 11 m long from e a s t t o west 7 . 5 m wide from north t o south and 2 . 7 m high.

In comparing ground temperatures in t he cen t r a l bo reho le of t h e v e n t i l a t e d embankment cons t ruc ted in 1974 w i t h t h a t o f experimental embankments No. 3 and N o . 2 of crushed stoney clayey loam, w e can see that the ground temperature of the former i s much lower than that o f t h e l a t t e r , (Table 9) .

During the year when t h e v e n t i l a t e d embankment w a s under cons t ruc t ion , t he permafros t t ab le d id not d rop , bu t in

214

t h e f i r s t y e a r a f t e r c o n s t r u c t i o n , t h e permafros t t ab le rose 0 .7 m. A S f o r embankment N o . 3 , which was b u i l t w i t h crushed stoney clayey loam, the permafrost t ab le under the embankment dropped consider- ab ly in the very year of cons t ruc t ion . In t h e f i r s t y e a r a f t e r c o n s t r u c t i o n t h e permafros t t ab le rose on ly 0 . 1 8 m (Table 1 0 ) . T h i s c l e a r l y shows t h a t t h e v e n t i l a t e d embankment i s comparatively good.

When adopt ing the p r inc ip le o f pro tec t ing the permafros t , coarse g ra ined s o i l i s genera l ly no t used for cons t ruc t ion of the embankment because it has h igher hea t conduc t iv i ty p rope r t i e s . However, when t h e embankments are constructed by p i l i n g up s tone b locks , condi t ions w i l l be qu i t e d i f f e r e n t . With t h e embankment body c u t t i n g o f f s o l a r r a d i a t i o n , t h e main h e a t t r a n s f e r w i l l . b e i n t h e form of convection. I n w i n t e r , t h e h i g h d e n s i t y c o l d a i r becomes heavier and can seep f ree ly in to the base course through the voids between the s tones making the under ly ing so i l ex t remely co ld . However, o n c e t h e a i r becomes warm, it w i l l be pushed out by the colder air . I n summer, on the o the r hand , t he ou t s ide warm a i r w i l l no t en te r the base course as f r e e l y a s t h e c o l d a i r d o e s i n w i n t e r . The r e s u l t i s t h a t it favours p ro tec t ion of the permafrost . According to experiments a t Reshui , it appea r s t ha t when t h e a i r f reezing index exceeds the thawing index, and in regions where the summer r a i n f a l l is low, t h i s t y p e of v e n t i l a t e d embankments w i l l be favourable fo r p ro t ec t ing t he pe rmaf ros t .

Ef fec t o f Water and Drainage Measures

Af te r cons t ruc t ion of the embankment, t h e movement of both the surface water and groundwater from the upper slope was in t e r rup ted . When d r a i n a g e f a c i l i t i e s are inadequate water o f t e n s t a g n a t e s on both s ides o f t he embankment and i n f i l t r a t e s in to the subgrade .

Experience i n the cons t ruc t ion of embankments p roves t ha t , whenever t h e r e i s stagnant water on bo th s ides o f t h e embankment and i n f i l t r a t i o n i n t o s u b g r a d e s , t h e permafros t t ab le i n most embankments w i l l drop. The d rop i n t he pe rmaf ros t t ab l e i s g r e a t e r , e s p e c i a l l y when water perco la tes in to’ the subgrade . The he igh t of t h e i n t e r c e p t i n g d i k e a t the Reshui Experimental Embankment N o . 2 i s only 0.5 m. I t i s no t high enough t o s t o p t h e s t a g n a n t s u r f a c e water and suprapermafrost water o u t s i d e the dike. Thus, the rise of the permafrost table under Embankment No. 2 is less. From Table 11, it is e v i d e n t t h a t t h e rise o f the permafros t t ab le is c l o s e l y r e l a t e d t o t h e amount of p r e c i p i t a t i o n i n t h e y e a r o f cons t ruc t ion . The higher the annual p r e c i p i t a t i o n , t h e more s tagnant water and suprapermafrost water there w i l l be o u t s i d e

the in te rcept ing d ike . Therefore , the rise of the permafros t t ab le w i l l be less too . Inves t iga t ions on the permafrost t ab le under the embankment i n t h e discontinuous permafrost zone i n t h e Greater Khingan Mountains i n n o r t h e a s t China have a lso proved this (Table 12). I n summer, the t empera ture in the nor th- e a s t i s higher than in the Reshui Region. The temperature of t h e s t a g n a n t water on the ground surface w i l l be correspondingly high. Therefore , the inf luence caused by water on the permafrost table under the embankment i n t h e n o r t h e a s t is g r e a t e r than that in the Reshui Region.

When adopt ing the p r inc ip le o f pro tec t ing the permafros t to bu i ld embankments i n t h e i c e r i c h s e c t i o n s n e a r the lower l i m i t of permafrost , it i s necessary tc? pay g r e a t a t t e n t i o n t o t h e d r a i n a g e f a c i l i t i e s .

I n 1 9 7 2 a d ra inage d i t ch , 1 5 m long, 0 . 6 m wide a t the bottom, 1 . 8 m wide a t the top and 0 . 6 m deep with 1:l s lopes was b u i l t a t t h e Reshui experimental embankment. A f t e r one year ’s use , the permafrost table below the bottom of the d i t c h had dropped 0 .54 m , bu t t he perma- f r o s t t a b l e , o n e metre from the edge of t h e d i t c h , had changed very l i t t l e . From da ta co l l ec t ed i n t he d i scon t inuous permafrost zone in the Greater Khingan Mountains, it was found t h a t t h e e x t e n t of hor izonta l in f luence o f the d i tch was only 1-3 m a f t e r 6 or 7 years. Therefore, a dra inage d i tch can genera l ly be bu i l t 5 m upward from t h e f o o t o f embankment. However, i n a section where ground ice is w e l l developed, especial ly a t shallow d e p t h s , t h e i n s t a l l a t i o n of a drainage d i t c h w i l l ce r ta in ly cause mel t ing o f it. Furthermore, drainage di tches can only i n t e r c e p t and s top surface water f low. I t cannot s top the suprapermafrost water . Therefore, when bui lding embankments on ice- r ich sec t ions near the lower limit of permafrost, water should be drained with an i n t e rcep t ing d ike . The dike should be bu i l t w i th impermeab le ma te r i a l , t o make the permafros t t ab le rise t o the ground surface. This w i l l s t op no t on ly t he surface water but a lso the groundwater . The minimum he igh t of an i n t e rcep t ing dike, needed to make the permafros t t ab le r ise t o t h e ground surface, can be ca lcu la ted wi th Formula ( 5 ) :

Ho = ’ + (?lb+Hoctga

/-$jT Fdt

Bo )Z .

215

\ Year I I ... Numerical Value

I tem \\ '\ 1 9 7 2

R i s e of Pe rmaf ros t Tab le i n Embankment No. 2 (M) l o

1973 I 1974

+0.42 +0.03

A n n u a l P r e c i p i t a t i o n (mm) 1 580 .0 I Annual Temperature Mean (OC) + 390 .5 509.2

Table 11 Permafros t Table under Embankment N o . 2 a n d t h e P r e c i p i t a t i o n

+[ 2 b + H ~ ~ t g u 1 2 is o n l y r e l a t e d t o t h e c r o s s - s e c t i o n of a n i n t e r c e p t i n g d i k e and is expressed by m.

Thus , Ho = mH

When t h e w i d t h a t t h e t o p i s 1 m and t h e s l o p e i s 1: 1 t h e v a l u e m a - t v a r i o u s va lues o f Ho w i l l b e l i s t e d i n t h e f o l l o w - i n g ( T a b l e 1 3 ) .

Ho can be c a l c u l a t e d by t r i a l a n d e r r o r .

C o n s i d e r i n g t h a t t h e h e i g h t of an i n t e r c e p t i n g d i k e i s r a r e l y more t h a n 5 m and it has a c e r t a i n s a f e t y c o e f f i c i e n t , it can be presumed that ,

Ho = 1.3 B ( 1 4 )

It i s n o t s u i t a b l e t o b u i l d a n i n t e r - c e p t i n g d i k e f a r f r o m t h e embankment. I n o r d e r t o r a p i d l y d r a i n away t h e s t a g n a n t water on t h e s u r f a c e , a s h a l l o w d i t c h may be dug 1 m f r o m t h e i n t e r c e p t i n g d i k e . Thus , pa r t of t h e w a t e r f l o w may b e l e d away. I t enhances t he t he rma l i n f luence of t h e s u r f a c e w a t e r on t h e i n t e r c e p t i n g d i k e a n d e n s u r e s t h e rise o f t h e permafrost t a b l e u n d e r t h e d i k e .

Long- te rm F luc tua t ion of A i r Temperature

The climate f l u c t u a t e s i n v a r i o u s ways a t d i f f e r e n t p e r i o d s of t i m e . The longer t h e f l u c t u a t i n g c y c l e , t h e b i g g e r t h e ampl i tude w i l l b e . I n t h e p a s t 1 0 , 0 0 0 y e a r s , t h e t e m p e r a t u r e i n C h i n a has expe r i enced t he fo l lowing fou r ma in f l u c t u a t i n g s t a g e s :

5-8OC i n t h e p a s t t e n t h o u s a n d y e a r s : 2OC i n t h e p a s t t h o u s a n d y e a r s ; lOC i n t h e p a s t h u n d r e d y e a r s ; 0.5-1. O°C i n t h e p a s t t w e n t y y e a r s .

I n r e g a r d t o r a i l w a y c o n s t r u c t i o n , it is necessa ry t o c o n s i d e r t h e t e m p e r a t u r e f l u c t u a t i o n o v e r a e r iod o f one hundred y e a r s , i .e . abou t 1 I: C .

C l i m a t i c v a r i a t i o n s o v e r t h e p a s t f i v e h u n d r e d y e a r s f r o m a n a l y s i s o f t h e a n n u a l r i n g s of a p i n e 913 y e a r s old, still growing a t t h e u p p e r f o r e s t limit, 3 , 6 0 0 m a . s . l . , i n T i a n j u n c o u n t y (37O24'N, 98O56'E) on t he sou the rn s lope of t h e Ch i l i an Moun ta ins i n Ch ingha i P rov ince and r e p o r t e d by t h e I n s t i t u t e o f t h e C e n t r a l Bureau o f Me teo ro logy , bas i ca l ly co inc ides w i t h t h e c l i m a t i c v a r i a t i o n s u m m a r i z e d by Chu KO-chen from t he r eco rds o f me teo ro logy a n d p h e n o l o g y i n t h e h i s t o r i c a l l i t e r a t u r e o f anc ien t Ch ina . Th i s con f i rms t ha t c l i m a t i c v a r i a t i o n s i n w e s t e r n C h i n a r e f l e c t e d i n t r e e - r i n g a n a l y s i s c o i n c i d e s w i t h t h a t of t h e e a s t e r n p a r t o f o u r coun t ry t o a c o n s i d e r a b l e e x t e n t . The g e n e r a l t e n d e n c y f o r cl imatic v a r i a t i o n i n t h e n e x t 1 0 0 y e a r s i n t h e r e g i o n f r o m S i d a t a n t o Ando, acco rd ing t o t h e a n a l y s i s of t r e e - r i n g s c o i n c i d e s a p p r o x i m a t e l y w i t h f u t u r e c l i m a t i c v a r i a t i o n s i n e a s t e r n C h i n a , a n d i n o t h e r p a r t s of t h e w o r l d . T h i s i s p r e d i c t e d by a n a l y z i n g s o l a r ac t iv i ty . Th i s t endency can be summar ized a s f o l l o w s :

The tendency of climatic v a r i a t i o n i n t h e coming 1 0 0 y e a r s i n t h e T a n g u l h a a r e a ( f rom S ida tan t o Ando) i s t h a t it w i l l be c o l d e r t h a n a t p r e s e n t e x c e p t for a s l i g h t warming i n t h e 1 9 8 0 s . The c o l d e s t p e r i o d w i l l be from 2 , 0 0 0 t o 2 , 0 1 0 and before and a f t e r 2 , 0 5 0 . It w i l l be about 0.5' t o 0.7oC lower t h a n now. A r e l a t i v e l y w a r m

0

N

a I

0

w 0

I

z 0

rlm

I 0

0

..

m 0

m

N

217

HO 0 0 . 5 1.0 1 . 5 2 . 0 3 . 0 5.0 10 .0 100.0

m 1 1 . 0 5 1.12 1-17 1 . 2 0 1 .25 1 - 3 0 1.35 1.41 1.41

Table 13 V a l u e of m a t v a r i o u s v a l u e s o f Ho

p e r i o d w i l l a p p e a r i n t h e 2,030s and 2,050s. The a i r t e m p e r a t u r e t h e n w i l l b e a b o u t 0.3oC h i g h e r t h a n now. The maximum a m p l i t u d e of t h e a i r t e m p e r a t u r e w i l l be 1 .0-1.50C. In t h i s g e n e r a l t r e n d , t h e r e w i l l be a small f l u c t u a t i o n w h i c h h a s a n a m p l i t u d e of a b o u t 0.5OC.

T h u s , t h e most d i s a d v a n t a g e o u s c o n d i t i o n is t h a t t h e mean a n n u a l a i r t e m p e r a t u r e w i l l r ise 20C o n e h u n d r e d y e a r s from now. Under such cond i t ions , i s it still p o s s i b l e t o cons t ruc t embankmen t s i n ice r i c h s e c t i o n s n e a r t h e lower limit on t h e p r i n c i p l e of p r o t e c t i n g t h e p e r m a f r o s t ?

I t has been known t h a t t h e c o n s t r u c t i o n of embankments has l i t t l e i n f l u e n c e o n t h e p e r m a f r o s t t a b l e i n a h o r i z o n t a l d i r e c t i o n , b u t t h e i n f l u e n c e becomes very g r e a t when it is i n a v e r t i c a l d i r e c t i o n . R e l a t i v e l y s p e a k i n g , cl imatic v a r i a t i o n g i v e s a g r e a t i n f l u e n c e when it i s i n a h o r i z o n t a l d i r e c t i o n , b u t smaller i n t h e v e r t i c a l d i r e c t i o n .

Accord ing t o Formula ( 2 ) , t h e maximum

depth of thaw of t h e s o i l i s h = /? R. It is a s s u m e d t h a t , u n d e r t h e same climatic c o n d i t i o n s , t h e maximum d e p t h of s e a s o n a l t h a w c a u s e d b y t h e d i f f e r e n c e i n water c o n t e n t a n d l i t h o l o g y h , = I t is a l r e a d y k n o w n t h a t , t h e r a t i o o f t h e maximum d e p t h of s e a s o n a l t h a w c a u s e d by d i f f e r e n t l i t h o l o g y a n d water c o n t e n t s c a n r e a c h " - 3. If l i t h o l o g y a n d water c o n t e n t do h, n o t c h a n g e w i t h cl imatic c o n d i t i o n s , t h e n ,

i f w e want - = 3 , it i s n e c e s s a r y t o make

2x

h h ,

;,= 9 . A s ment ioned above , the mos t d i s a d v a n t a g e o u s c o n d i t i o n i n t h e n e x t 1 0 0 y e a r s w i l l b e t h e rise of t h e mean a n n u a l a i r t e m p e r a t u r e b y 2OC. T h i s c a n h a r d l y

make = 9 . I n o t h e r w o r d s , t h e d i f f e r e n c e of L i t h o l o g y a n d water c o n t e n t w i l l p roduce a much g r e a t e r d i f f e r e n c e i n t h e p e r m a f r o s t t ab le t h a n t h a t c a u s e d b y t h e f l u c t u a t i o n o f t e m p e r a t u r e w i t h i n o n e h u n d r e d y e a r s . T h a t i s t o s a y , w i t h i n t h e c o n t e x t of a rise o f a i r t e m p e r a t u r e a n d d e g r a d a t i o n of t h e p e r m a f r o s t , t h e c h o o s i n g of ideal

51

embankment m a t e r i a l a n d d e s i g n c a n still create c o n d i t i o n s c a u s i n g t h e p e r m a f r o s t t ab le t o rise.

I t c a n also be s e e n t h a t , a f t e r h a v i n g c o n s t r u c t e d a n e m b a n k m e n t o n t h e p r i n c i p l e of p r o t e c t i n g t h e p e r m a f r o s t , t h e g r o u n d ice a t t h e o r i g i n a l p e r m a f r o s t t a b l e w i l l b e f a r t h e r f r o m t h e s u r f a c e . T h u s , t h e d i f f e r e n c e i n g r o u n d t e m p e r a t u r e a t t h e o r i g i n a l p e r m a f r o s t t ab le a n d t h e h e a t a r r i v i n g t h e r e w i l l dec rease . The embankment will b e slow i n r e a c t i n g t o t h e c h a n g e of climate. The r e s u l t w i l l b e a d v a n t a g e o u s t o t h e p r e s e r v a t i o n of ground ice.

F u r t h e r m o r c , some c o r r e l a t i o n s e x i s t b e t w e e n t h e t e m p e r a t u r e a n d t h e s t a t e of t h e p e r m a f r o s t . G e n e r a l l y , t h e lower t h e t e m p e r a t u r e of t h e p e r m a f r o s t , t h e g r e a t e r i t s t h i c k n e s s w i l l be. The t empera tu re is s e n s i t i v e t o c l i m a t i c c h a n g e b u t t h e s ta te o f t h e p e r m a f r o s t h a s v e r y g r e a t " t h e r m a l i n e r t i a " . T h u s , it reacts v e r y s l o w l y t o climatic change . The h ighe r t he ice c o n t e n t i n t h e p e r m a f r o s t , t h e g r e a t e r t h e " t h e r m a l i n e r t i a " w i l l be . Obse rva t ion data from t h e e x p e r i m e n t a l embankment a t t h e B r a n c h L i n e i n n o r t h e a s t C h i n a i n d i c a t e d t h a t , e v e n i f t h e embankment was c o n s t r u c t e d i n summer a n d c o n t a i n e d a l a r g e amount of s t o r e d h e a t , i n t h e t h i c k p e a t l a y e r s w i t h h i g h ice c o n t e n t , t h e p e r m a f r o s t t a b l e would n o t d r o p (Table 8 ) . It is s u f f i c i e n t t o n o t e how l a r g e t h e " t h e r m a l i n e r t i a " i s . T a b l e ( 1 4 ) l i s t s t h e r e l a t i o n s b e t w e e n t h e change o f a i r t empera tu re and t he pe rma- f r o s t t a b l e ( t h e r e were ground ice L a y e r s a t t h e p e r m a f r o s t t a b l e ) i n R e s h u i R e g i o n . I t i s e v i d e n t f r o m t h e t ab le t h a t , i n s p i t e of t h e g r a d u a l rise of a i r t e m p e r a t u r e f r o m y e a r t o y e a r , t h e r e is n o c h a n g e i n t h e p e r m a f r o s t t ab le . I n f a c t , it i s t h e c o a r s e - g r a i n e d s o i l t h a t d e g r a d e s r a p i d l y . T h e s o i l h a s l o w ice c o n t e n t , a l t h o u g h t h e m e c h a n i c a l p r o p e r t i e s are n o t so poor a f t e r thawing. On t h e c o n t r a r y , i n s p i t e of t h c f i n e - g r a i n e d soils w i t h h i g h ice c o n t e n t , it h a s p o o r m e c h a n i c a l p r o p e r t i e s a f t e r thawing. However, because of i t s l a r g e " t h e r m a l i n e r t i a " , a n d t h e slow thawing , t he annua l amoun t o f t hawing caused by t h e l o n g - t e r m f l u c t u a t i o n i n cl imate w i l l be small, too. As l o n g a s a c e r t a i n amount of s e t t l e m e n t i s allowed i n t h e d e s i g n a n d t h e r e i s y e a r l y m a i n t a n a n c e , n o g r e a t d i f f i c u l t i e s w i l l o c c u r .

218

I tern . 1 9 7 0 1 9 7 2 1 9 7 3

Mean Annual I Temperature ( C ) I - 2 * 9

I - 2 . 6 I -2 .0 1 -2 .2

permafros t Table under Embankment No. 2 (m) 1 . 5 1.5 1 . 5 1.5

I I I

permafros t

P r a c t i c e s i n embankment c o n s t r u c t i o n a l s o p r o v e d t h a t , e v e n i f t h e embankment a r e c o n s t r u c t e d a c c o r d i n g t o t h e p r i n c i p l e o f p r o t e c t i n g t h e p e r m a f r o s t i n t h e r e g i o n where it is d e g r a d i n g , t h e p e r m a f r o s t t a b l e u n d e r t h e embankment w i l l f i n a l l y rise up as long as p rope r measu res a r e taken .

Gene ra l ly , w e c o n s i d e r t h a t t h e perma- f r o s t i n t h e R e s h u i R e g i o n is going th rough a s t a g e o f d e g r a d a t i o n . N e v e r t h e l e s s , t h e p e r m a f r o s t t a b l e u n d e r t h e R e s h u i expe r imen ta l embankment, i n c l u d i n g i t s i n t e r c e p t i n g d i k e s , i s r i s i n g ( T a b l e 3). The r e s u l t o f a n a t o m i z i n g t h e b a n k s a t t h r e e l o c a t i o n s i n t h i s r e g i o n (some of t hem have ex i s t ed fo r more t h a n t e n y e a r s ) shows t h a t t h e p e r m a f r o s t t a b l e u n d e r t h e embankments h a s r i s e n by varying amounts (Table 15).

The r a i l w a y s e c t i o n f r o m J i a g e d a q i t o X i n t i a n i n n o r t h e a s t C h i n a b e l o n g s t o t h e pe rmaf ros t boundary r eg ion on t he ea s t e rn s l o p e of the Greater Khingan Mountains . The permafros t occurs in small s c a t t e r e d i s l a n d s , w i t h mean annual ground temper- a t u r e o f 0 t o -1. O°C and the permafros t i s 4-6 m t h i c k . I t is c o n s i d e r e d g e n e r a l l y , t h a t t h e p e r m a f r o s t t h e r e i s i n a s t a g e o f deg rada t ion . The a i r t e m p e r a t u r e i n t h i s r e g i o n c h a n g e s c o n s i d e r a b l y e a c h y e a r . D e s p i t e t h a t , t h e r a i l w a y i n t h e r e g i o n f r o m J i a g e d a q i t o X i n t i a n w a s c o n s t r u c t e d o n t h e p r i n c i p l e of p r o t e c t i n g the permafros t . Cons t ruc t ion was comple ted i n 1965 . I n v e s t i g a t i o n s were made o n t h e r a i lway i n 1971 and 1972 . They p roved t ha t w i t h t h e e x c e p t i o n o f t h o s e u n d e r t h e b a s e c o u r s e o f t h e embankments wi th water per - c o l a t i o n , t h o s e u n d e r t h e h i g h embankments a n d t h o s e u n d e r t h e s u n n y s l o p e of t h e embankments, t h e r e i s a rise of t h e perma- f r o s t t a b l e t o vary ing degrees under most of t h e embankment c ros s - sec t ion (Tab le 1 6 ) .

I n summary, w e c o n s i d e r t h a t n e a r t h e lower limit and southern l i m i t of t h e pe rmaf ros t , even i f t h e g r o u n d t e m p e r a t u r e is high and t h e p e r m a f r o s t is going th rough

Tab le 1 4 Change of a i r temperature and . t ab l e i n Reshu i Reg ion

a s t a g e o f d e g r a d a t i o n , t h e c o n s t r u c t i o n of embankments on t h e p r i n c i p l e of pro- t e c t i n g t h e p e r m a f r o s t c a n c a u s e t h e p e r m a f r o s t t a b l e t o rise u n d e r c e r t a i n c o n d i t i o n s a n d e n s u r e t h e s t a b i l i t y o f t h e embankments a s l o n g a s t h e p e r m a f r o s t p e r s i s t s a s a s i n g l e body.

CONCLUSIONS

From t h e a b o v e d i s c u s s i o n , w e have come t o t h e f o l l o w i n g c o n c l u s i o n :

1) Even i f t h e c l i m a t e becomes warmer and thk permafrost degrades somewhat, r e a s o n a b l e c o n s t r u c t i o n o f t h e embankments can still c r e a t e f a v o u r a b l e c o n d i t i o n s fo r the p re se rva t ion and deve lopmen t o f perma- f r o s t , and f o r t h e rise of t h e p e r m a f r o s t t a b l e u n d e r embankment;

2 ) S u r f a c e water and groundwater are t h e m a i n c a u s e s f o r t h e p e r m a f r o s t t a b l e t o drop under embankments. Therefore, good d r a i n a g e o n t h e s i d e s of embankments is an i m p o r t a n t m e a s u r e t o e n s u r e t h e i r s t a b i l i t y a n d c a r e f u l a t t e n t i o n m u s t b e g iven t o t h i s . An i n t e r c e p t i n g d i k e c a n k e e p n o t o n l y s u r f a c e water, b u t a l s o groundwater f rom the upper s lope and is s t r o n g l y recommended;

3 ) From t h e v i e w p o i n t o f h e a t c o n d u c t i v i t y , it i s b e t t e r t o select a soil. ( s u c h a s c l a y e y soil) f o r embankment material w i t h g r e a t e r d i f f e r e n c e s b e t w e e n t h e r m a l c o n d u c t i v i t y i n t h e f r o z e n s ta te and t he t hawed s t a t e ;

4 ) When t h e f r e e z i n g i n d e x i n t h e r e g i o n i s g rea t e r t han t he t hawing i ndex , and t h e summer p r e c i p i t a t i o n is l o w (or t h e summer a i r t e m p e r a t u r e i s n o t v e r y h i g h ) , t h e u s e o f v e n t i l a t e d embankments ( p i l e d u p w i t h s t o n e b l a c k s , v e n t i l a t i n g p i p e s ) w i l l be f avourab le far p r o t e c t i n g the pe rmaf ros t ;

5) The embankment h e i g h t h a s t o b e g r e a t e r t h a n t h e minimum h e i g h t t h a t can

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c a u s e t h e o r i g i n a l p e r m a f r o s t table t o be unchanged. However, it s h o u l d n o t b e too h i g h . I t is n o t s u i t a b l e t o have an embankment h i g h e r t h a n 6 m n e a r t h e Lower l i m i t of p e r m a f r o s t . When it e x c e e d s 6 m, prope r measu res must be t a k e n - e .g . when c o n s t r u c t i o n is carried o u t i n w i n t e r , t h e i n s u l a t i o n s h o u l d b e i n c r e a s e d .

6 ) T h e h i g h e r t h e l a t i t u d e , t h e more e v i d e n t t h e i n f l u e n c e o f slope o r i e n t a t i o n will be. On east-west s e c t i o n s of t h e l i n e it i s n e c e s s a r y t o i n c r e a s e t h e i n s u l a t i o n o n s u n n y s l o p e s when t h e embankment i s too h igh:

7 ) An ice r i c h s e c t i o n n e a r t h e lower l i m i t of p e r m a f r o s t i s n o t s u i t a b l e for c o n s t r u c t i o n of embankments o r i n s u l a t i n g b e r m s i n summer;

8) Long-term a i r t e m p e r a t u r e f l u c t u a t i o n s h a v e some real s i g n i f i c a n c e to r a i l w a y c o n s t r u c t i o n i n t h e d i s c o n t i n u o u s p e r m a f r o s t z o n e w h e r e t h e mean annual g round t e m p e r a t u r e i s n e a r zero, a n d t h e mean a n n u a l g r o u n d s u r f a c e t e m p e r a t u r e is above - 2 o c t o -3OC.

9 ) T h e i n f l u e n c e o f u r b a n b u i l d i n g d e v e l o p m e n t s o n d i s c o n t i n u o u s p e r m a f r o s t is so complex t ha t more effor ts s h o u l d be made t o s t u d y t h e p r o b l e m i n t h e f u t u r e .

I n c o n c l u s i o n , it is p o s s i b l e t o c o n s t r u c t e m b a n k m e n t s o n t h e p r i n c i p l e o f p r o t e c t i n g t h e p e r m a f r o s t i n s e c t i o n s w i t h ground ice n e a r t h e lower l i m i t o f t h e a l p i n e p e r m a f r o s t . However, because of t h e in f luences o f Long- t e rm a i r t e m p e r a t u r e f l u c t u a t i o n s a n d human ac t iv i t ies , f u r t h e r s t u d y i n t h i s f i e l d m u s t b e carried o u t t o d e v e l o p r e g u l a t i o n s f o r a p p l y i n g t h i s p r i n c i p l e.

ACKNOWLEDGEMENT

T h e f i e l d w o r k r e f e r r e d t o i n t h i s p a p e r was s u p p o r t e d b y t h e R e s h u i P e r m a f r o s t Team. T h e T h i r d D e s i g n R a i l w a y I n s t i t u t e h a s p r o v i d e d many v a l u a b l e d a t a . T h e a u t h o r s g r a t e f u l l y a c k n o w l e d g e t h e c o o p e r a t i o n of t h e T h e r m a l G r o u p , a n d p a r t i c u l a r l y t h a t o f Comrade Xu X i a o - z u f o r r e v i e w i n g t h e m a n u s c r i p t .

REFERENCES

1. P r o g r e s s r e p o r t on r e g u l a t i o n s of c h a n g e i n t h e a r t i f i c i a l p e r m a f r o s t t ab l e under embankments i n t h e p e r m a f r o s t r e g i o n of t h e Greater Khingan Mountains , 1973 . T h i r d D e s i g n R a i l w a y s I n s t i t u t e , M i n i s t r y of Communications.

2 .

3 .

4 .

5 .

O b s e r v a t i o n r e p o r t o n e x p e r i m e n t a l embankment of t h e Huchung Branch Line i n t h e p e r m a f r o s t r e g i o n of t h e Greater Khingan Mountains, 1973 . Th i rd Des ign R a i l w a y s I n s t i t u t e , M i n i s t r y of Communications.

Chu Ko-chen. 1972. I n i t i a l r e s e a r c h o n c l imat ic change t h rough f i v e t h o u s a n d y e a r s i n C h i n a , Kaogu J o u r n a l of Archaeology.

Porkhaev, G.V. 1 9 6 1 . I n f l u e n c e o f c o n s t r u c t i o n o n h e a t and m o i s t u r e reg ime of p e r m a f r o s t . Materials F o r Study of Frozen Zones o f t h e E a r t h ' s C r u s t , VoL. 7 ( I n R u s s i a n ) . Lo Xue-po. 1 9 7 4 . An a p p r o x i m a t e s o l u t i o n o f m a t h e m a t i c a l q u e s t i o n s i n p e r m a f r o s t s t u d i e s .

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2 .

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B o r e h o l e N o . 6 i n embankment N o . 2 .

L a y o u t a n d b o r e h o l e l o c a t i o n s in expe r imen ta l embankmen t .

Rate of s e t t l e m e n t o f t h e experimental embankment .

Relation between embankment h e i g h t H a n d s e t t l e m e n t .

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T o many of u s t h e h a p p y d a y s of fellow- s h i p a t t h e F i r s t I n t e r n a t i o n a l C o n f e r e n c e o n P e r m a f r o s t h e l d a t P u r d u e U n i v e r s i t y i n L a f a y e t t e , I n d i a n a , w i l l seem a s i f t h e y were b u t y e s t e r d a y . B u t almost f i f t e e n y e a r s h a v e p a s s e d s i n c e t h e n , f i f t e e n y e a r s of p r o g r e s s o n many f r o n t s , a n d of g r e a t p r o g x e s s i n o u r own s p e c i a l f i e l d of i n t e r - es t , as t h e p a p e r s b e i n g p r e s e n t e d a t t h i s , t h e T h i r d C o n f e r e n c e , make c l e a r . Our h o s t a t t h a t f i r s t C o n f e r e n c e , P r o f e s s o r K . B. Woods, a l t h o u g h r a t h e r s e r i o u s l y h a n d i c a p p e d p h y s i c a l l y , r e t a i n s h i s l i v e l y i n t e r e s t a n d w i l l b e g l a d t o h e a r o f t h e s u c c e s s of t h i s c o n t i n u a t i o n o f t h a t p i o n e e r v e n t u r e a t Purdue .

To my v e r y g r e a t r e g r e t , d u t i e s i n Canada prevented m e f r o m a t t e n d i n g t h e Second Confe rence i n Yaku t sk bu t many f r i e n d s who were t h e r e h a v e t o l d m e of t h e welcome t h e y r e c e i v e d a n d of t h e i r e n j o y - ment of b o t h m e e t i n g s a n d v i s i t s . I w a s e s p e c i a l l y s o r r y n o t t o h a v e had t h e o p p o r - t u n i t y of m e e t i n g my g o o d f r i e n d s D r . Melnikov and Dr. Vyalov on t h e i r own terri- t o r y , a f t e r t h e p l e a s u r e o f w e l c o m i n g t h e m t o Canada; I migh t even have hea rd some of t h e i r S o v i e t f i s h stories, t o set a g a i n s t t h e i r f i s h i n g p r o w e s s i n t h i s c o u n t r y . I would have been too e a r l y , h o w e v e r , t o see o n e of t h e most r e m a r k a b l e o f a l l S o v i e t p e r m a f r o s t d i s c o v e r i e s , t h e b a b y mammoth o n l y s e v e n t o e i g h t m o n t h s o l d t h a t was f o u n d p e r f e c t l y p r e s e r v e d j u s t a f e w months a g o i n t h e Kolyma Berezovka pe rmaf ros t area t h r o u g h t h e q u i c k r e a c t i o n of a b u l l d o z e r o p e r a t o r (Anon 1 9 7 8 ) . I n Alaska a f i v e t o s i x y e a r o l d mammoth has been found w e l l - p r e s e r v e d i n p e r m a f r o s t . B u t ' i n C a n a d a a l l w e have so f a x f o u n d a re a few mammoth bones.

T h r e e d a y s o f t h i s C o n f e r e n c e h a v e now been en joyed ; one is y e t t o come and t hen f o l l o w t h e f i e l d t r i p s . W e h a v e t h e r e f o r e well p a s s e d t h e h a l f w a y m a r k of t h e formal d e l i b e r a t i o n s . T h i s most p l e a s a n t social

* Past Director, D i v i s i o n o f B u i l d i n g Resea rch , Na t iona l Resea rch Counc i l of Canada, Ottawa, On ta r io , Canada .

o c c a s i o n p r o v i d e s us, t h e r e f o r e , w i t h a u s e - f u l b r e a t h i n g s p e l l , a n d a c h a n c e t o s i t b a c k a n d t a k e a more g e n e r a l l o o k a t o u r f i e l d of i n t e r e s t . You do n o t w a n t f r o m m e a n o t h e r s e r i o u s t e c h n i c a l p a p e r - and OUT charming ladies w o u l d n o t s t a n d f o r a n y s u c h a n t i s o c i a l a c t on my p a r t . Y e t o u r e v e n i n g t o g e t h e r s h o u l d n o t p a s s i n t o memory w i t h o u t some r e c o g n i t i o n o f t h e f a c t t h a t we are g a t h e r e d h e r e , from a r o u n d t h e g l o b e , b e c a u s e o f o u r m u t u a l i n t e r e s t i n p e r m a f r o s t , t h a t c o n d i t i o n of t h e e a r t h ' s c r u s t when it is p e r e n n i a l l y f r o z e n , a n d i n a l l t h e c o n - s e q u e n c e s w h i c h r e s u l t f r o m t h e d i s t u r b a n c e of t h a t c o n d i t i o n s u c h as r e c e n t n o r t h e r n developments have made so clear.

L e t u s t h e n t a k e s t o c k of w h a t t h i s Conference i s cons ide r ing . Abou t 1 5 0 p a p e r s are b e i n g p r e s e n t e d or summar ized , au tho r s coming from no less t h a n f i f t e e n c o u n t r i e s , d e s p i t e t h e g e n e r a l r e s t r i c t i o n of perrna- f r o s t t o n o r t h e r n t e r r a i n s . S i x t y - t h r e e p e r c e n t , o r almost two t h i r d s , of t h e p a p e r s d e s c r i b e p e r m a f r o s t phenomena i n t h e f i e l d or p r a c t i c a l e x p e r i e n c e i n v o l v i n g its d i s t u r b a n c e . T w e n t y - t w o p e r c e n t of t h e p a p e r s d e s c r i b e l a b o r a t o r y s t u d i e s , a n d f o u r t e e n p e r c e n t p r e s e n t t h e o r e t i c a l a n a l y s e s . T h i s j u d i c i o u s b a l a n c e b e t w e e n t h e p r a c t i c a l a p p r o a c h a n d n e c e s s a r y b u t c o m p l e m e n t a r y l a b o r a t o r y a n d a n a l y t i c a l s t u d i e s i s g r e a t l y t o be welcomed. I t i s a b a l a n c e t h a t i s (alas!) s a d l y l a c k i n g i n o t h e r b r a n c h e s of Geotechnique .

Your e x p e r t i s e i n m e n t a l arithmetic will have shown you, I a m s u r e , t h a t t h e r e i s still o n e p e r c e n t of t h e p a p e r s u n a c c o u n t e d f o r . T h e r e are j u s t two pape r s t h a t d e a l w i t h f o s s i l p e r m a f r o s t f o r m a t i o n s . T h i s i s p a s s i n g s t r a n g e , a t f irst s i g h t , i n view of t h e e x t e n s i v e l i t e r a t u r e , e s p e c i a l l y i n E u r o p e a n j o u r n a l s , o n t h i s t o p i c . S e c o n d though t s , , however , g ive a more r a t i o n a l a p p r e c i a t i o n . T h i s C o n f e r e n c e i s b e i n g h e l d i n N o r t h America w h e r e c u r r e n t n o r t h e r n p r o - b l e m s i n v o l v i n g p e r m a f r o s t are v i t a l and u r g e n t - a s t h e y are a l so i n t h e n o r t h e r n r e g i o n s o f t h e U . S . S . R . and of t h e P e o p l e ' s R e p u b l i c of China . The Organiz ing Committee t h e r e f o r e d e c i d e d , v e r y u n d e r s t a n d a b l y if I may say so, t o c o n c e n t r a t e t h e a t t e n t i o n of

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t h i s C o n f e r e n c e o n t h e s e matters of c u r r e n t c o n c e r n . So you w i l l p r o b a b l y f i n d more a t t e n t i o n b e i n g p a i d t o f o s s i l p e r m a f r o s t f e a t u r e s a t f u t u r e C o n f e r e n c e s , n o t o n l y a s matters of g r e a t s c i e n t i f i c a n d a r c h a e o - l o g i c a l i n t e r e s t , b u t a l so f r o m v e r y p r a c t i c a l p o i n t s o f v i e w .

S e r i o u s t r o u b l e h a s a l r e a d y b e e n e x p e r i e n c e d i n Great B r i t a i n i n t h e s i n k i n g of l a r g e s h a f t s ( f o r tunne l work ) t h rough the wel l -known Chalk of sou the rn Eng land , w h e r e t h e u p p e r s u r f a c e was found t o be d i s i n t e g r a t e d ( t o a d e p t h o f a l m o s t s i x t y f e e t ) i n a m a n n e r t h a t c o u l d o n l y b e e x p l a i n e d as t h e r e s u l t o f p e r m a f r o s t (Haswell 1 9 6 9 ) . The f r a c t u r e d r o c k was s t i l l so " t i g h t " t h a t i t s t r u e n a t u r e was n o t r e v e a l e d by normal t es t d r i l l i n g p r o - c e d u r e s . T h a t t h i s i s n o i s o l a t e d phenomenon i s p e r h a p s i n d i c a t e d b y t h e f a c t t h a t I c o u l d t a k e you t o a n i s l a n d i n e a s t e r n Canada and there show you an e x p o s u r e of a r g i l l i t e t h a t a p p e a r s t o be good, so l id and compe ten t rock bu t wh ich i s a c t u a l l y c o m p l e t e l y f r a c t u r e d i n t o i n c h - Long f r a g m e n t s . 1 s u s p e c t t h a t some f o u n d a t i o n p r o b l e m s i n c i v i l e n g i n e e r i n g p r a c t i c e a re d u e t o u n s u s p e c t e d f o s s i l p e r m a f r o s t f e a t u r e s , o f w h i c h w e may e x p e c t t o h e a r more when t h e p r o b l e m s of t h e d a y p e r m i t

But I a m g c t t i n g t e c h n i c a l a n d t h i s I mus t no t do! L e t m e t h e n o b s e r v e t h a t e v e n m o r e s u r p r i s i n g t h a n t h e f e w p a p e r s o n f o s s i l p e r m a f r o s t i s t h e c o m p l e t e a b s e n c e o f a n y e x t e n d e d r e f e r e n c e t o t h e h i s t o r y o f s t u d i e s o f p e r m a f r o s t . Some of my younger f r i e n d s , i n t h e m a n n e r o f t h e d a y , may be tempted t o r e g a r d t h i s as p e r f e c t l y n a t u r a l and p rope r . They would like t o s a y , p e r h a p s , " S o what?" - ox a t l eas t t o a sk wha t re le - v a n c e a n y r e c o r d o f w o r k d o n e y e a r s a g o c a n have t o t h e i r c u r r e n t s t u d i e s o f p r a c t i c a l and u r g e n t p r o b l e m s . N o t h i n g d i r e c t l y , p e r h a p s , o n e m u s t a d m i t ; a n d y e t a s back- g r o u n d t o a l l t h e s p l e n d i d w o r k b e i n g d o n c t o d a y , s u r e l y some g e n e r a l a p p r e c i a t i o n of t h e work of t h o s e who have gone be fo re can h a v e r e a l v a l i d i t y . I t has been well s a i d t h a t " H i s t o r y i s as u s e l e s s , b u t as i m p o r t a n t , a s p o e t r y a n d m u s i c . " P o e t r y , d e s p i t e o c c a s i o n a l e u l o g i e s of t h e b e a u t i e s o f ice and snow (but never permafros t ) has p r o b a b l y n o p l a c e here t o n i g h t . I n a n y case, I am n o p o e t , a s must by now b e v e r y o b v i o u s from my p l o d d i n g p e d e s t r i a n p r o s e . B u t p e r h a p s t h e e q u i v a l e n t of a minor m u s i c a l i n t e r l u d e t o y o u r w e i g h t y d e l i b e r - a t i o n s may n o t b e o u t of p l a c e . And w e c a n a l l r eca l l t h e r e m a r k o f a v e r y d i s t i n g u i s h e d v i s i t o r t o t h e A u g u s t p r o c e e d i n g s of t h e B r i t i s h House of Commons i n W e s t m i n s t e r , t h e "Mother o f Par l iaments" who, when asked what h e t h o u g h t o f t h e d e b a t e t o which he had l i s t e n e d , s a i d t h a t it would have sounded much b e t t e r i f t h e r e h a d b e e n a n o r c h e s t r a .

I f , sometime, you care t o g l a n c e a g a i n a t t h e v o l u m e o f P r o c e e d i n g s o f t h e F i r s t C o n f e r e n c e , y o u w i l l f i n d t h a t t h e t w o p a p e r s g i v e n a t t h e o p e n i n g s e s s i o n d i d t o u c h u p o n t h e h i s t o r y of e a r l y perma- f r o s t i n v e s t i g a t i o n s b o t h i n t h e U.S .S .R. and Nor th America (Legge t and Tsy tov ich , ( 1 9 6 3 ) . My good f r i end Academic ian T s y t o v i c h , w h o s e a b s e n c e f r o m t h i s m e e t i n g w e so g r e a t l y r e g r e t , g a v e some i n t e r e s t i n g d e t a i l s of e a r l y r e c o r d s i n R u s s i a n l i t e r - a t u r e , s u c h as a n e a r l y o b s e r v a t i o n o f 1 6 6 2 , a n d M i d d e n d o r f ' s r e c o r d s of p e r m a f r o s t t e m p e r a t u r e s i n 1 8 4 8 . H e reminded us a lso of t h e p u b l i c a t i o n i n h i s c o u n t r y of a vo lume on pe rmaf ros t a s e a r l y a s 1927. N o t h i n g w a s s a i d i n t h e s e p a p e r s , q u i t e n a t u r a l l y , a b o u t e a r l y C h i n e s e r e c o r d s of p e r m a f r o s t s tud ies . N o w t h a t w e a re h e a r - i n g , f o r example , abou t some o f t h e u n i q u e a n d r e m a r k a b l e C h i n e s e r e c o r d s of e a r t h - q u a k e s i n t h a t c o u n t r y , I v e n t u r e t o hope t h a t o u r f r i e n d s f r o m t h e P . R . C . w i l l be a b l e t o produce fo r u s , o n e d a y , e a r l y r e c o r d s o f C h i n e s e p e r m a f r o s t s t u d i e s t h a t w i l l p u t i n t h e s h a d e , so t o speak , even t h e oldest r e c o r d s w e have of o b s e r v a t i o n s i n this p a r t o f t h e w o r l d .

Thinking o f t h e small gap be tween ou r t w o c o n t i n e n t s across B e r i n g S t r a i t , I may a l so n o t e t h a t l i t t l e was s a i d i n t h e P u r d u e p a p e r s a b o u t a n y e a r l y s t u d i e s of p e r m a f r o s t i n A l a s k a . T o d a y , w e a r e a l l f a m i l i a r w i t h t h e way i n w h i c h p e r m a f r o s t p r o b l c m s h a v e b e e n t a c k l e d i n t h a t l a r g e s t S t a t e o f t h c U n i o n , n o t o n l y f r o m t h e e a r l y work o f t he U . S . Crops of E n g i n e e r s b u t also, a n d n o t a b l y , f r o m t h e c o n s t r u c t i o n o f t h e A l y e s k a P i p e l i n e , so g r a p h i c a l l y d e s c r i b e d a t t h i s m e e t i n g . L e t m e r emind you , t hen , t h a t it was a Danish sea c a p t a i n , t h e n i n t h e employ of the Russ ian Government , Vi tus B e r i n g , who f i r s t s i g h t e d t h e l a n d of A l a s k a ( B a n c r o f t 1 8 8 6 ) . T h i s was o n h i s second voyage of e x p l o r a t i o n i n 1 7 4 1 when h e saw Mount S t . E l i a s and l anded some of h i s s a i l o r s o n t h e coast on 1 7 J u l y of t h a t y e a r ; t h e y were, t h e r e f o r e , t h e f i r s t w h i t e men t o set f o o t upon t h i s n o r t h - w e s t e r n p a r t of N o r t h America. (1 have sometimes wondered i f t h e r e was any h idden s i g n i f i c a n c e i n t h e f a c t t h a t o n B e r i n g ' s f i r s t v o y a g e , of 1 7 2 8 , t h e coast of Alaska was s h r o u d e d i n s u c h t h i c k f o g t h a t , a l t h o u g h p r o b a b l y n e a r t o it, B e r i n g d i d n o t t h e n see it.) I t is sad t o t h i n k t h a t t h i s i n t r e p i d man d i e d m i s e r a b l y o n 8 December o f t h a t same y e a r ( 1 7 4 1 ) .

O t h e r e x p l o r e r s f r o m R u s s i a f o l l o w e d , t h e f i r s t p e r m a n e n t se t t lers l o c a t i n g n e a r K o d i a k i n 1 7 8 4 . T h e r e i s still i n e x i s - t e n c e , I b e l i e v e , t h e j o u r n a l o f Z a i k o v (of 1783) and i n t h i s are some o b s e r v a t i o n s o f N a g a r i o v , d i s c o v e r e r o f t h e C o p p e r River. One would expect t o f i n d h e r e some r e f e r e n c e t o p e r m a f r o s t b u t I do n o t know

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i f t h i s reference h a s b e e n s t u d i e d from t h i s p o i n t of view. T h i s was a n a g e o f g r e a t a n d many e x p l o r a t i o n s . T h e S p a n i a r d s , t h e r e f o r e , a l so saw t h e coast o f A laska i n 1 7 7 5 and some of t h e i r o r i g i n a l j o u r n a l s from t h e s e v o y a g e s a x e said still. t o be e x t a n t . S p a n i s h A r c h i v e s m i g h t , t h e r e f o r e , y i e l d i n f o r m a t i o n s u r p r i s i n g l y g e r m a n e t o o u r common I n t e r e s t . So a lso m i g h t t h e r e c o r d s of a F r e n c h n a v i g a t o r , L e PGrouse, who sailed a l o n g t h e A l a s k a n coast i n 1 7 8 6 . Soon a f t e r t h i s came t h e y e a r s o f t h e Russ ian Amer ican Company ( f o u n d e d i n 1 7 9 9 ) b u t I feel s u x e t h a t o u r S o v i e t f r i e n d s h a v e a l r e a d y d u g d e e p l y i n t o t h e r e c o r d s o f t h i s s i n g u l a r l y i n t e r e s t i n g p i o n e e r commercial v e n t u r e ( B a n c r o f t 1886).

J u s t l y f a m o u s as was t h e R u s s i a n American Company, I t r u s t t h a t o u r S o v i e t g u e s t s w i l l f o r g i v e m e i f I p o i n t o u t t h a t w e h a v e i n C a n a d a a n e v e n o l d e r commercial company. I ment ion it o n l y b e c a u s e some of i t s e a r l y r e c o r d b o o k s h a v e a l r e a d y y i e l d e d i n t e r e s t i n g i n f o r m a t i o n a b o u t e a r l y p e r m a f r o s t o b s e r v a t i o n s i n t h i s c o u n t r y . I r e f e r , of c o u r s e , t o "The Governor and Company of A d v e n t u r e r s t r a d i n g i n t o H u d s o n ' s Bay" , today more commonly known a s t h e Hudson's Bay Company, t h e o l d e s t commercial company i n t h e w o r l d . I n c o r p o r a t e d o n 2 May 1 6 7 0 , o n e f e a t u r e of i t s r e c e n t t e r c e n t e n a r y was t h e t r a n s f e r of i t s Head O f f ice and i t s i n v a l u a b l e A r c h i v e s f r o m London, England, t o Winn ipeg . E igh t yea r s o l d e r t h a n t h e H o n o r a b l e Company i s t h e R o y a l S o c i e t y of London, t h e o l d e s t s c i e n t i f i c s o c i e t y o f t h e w e s t e r n w o r l d . And o f t h e e i g h t e e n o r i g i n a l " A d v e n t u r e r s " named i n t h e C h a r t e r o f t h e Company, no less t h a n s i x were (or became) Fellows of t h e R o y a l S o c i e t y ( S t e a r n s 1 9 4 5 ) .

T h i s l i n k b e t w e e n commerce a n d s c i e n c e i s still t o d a y , a s w e s h a l l s h o r t l y see, a h a p p y f e a t u r e of o u r n o r t h e r n d e v e l o p m e n t . I t was e v i d e n c e d i n t h e e a r l y d a y s b y t h e q u e s t i o n n a i r e w h i c h t h e R o y a l S o c i e t y p e r s u a d e d e a r l y t rave l le rs a n d e x p l o r e r s t o answer. There i s s t i l l i n e x i s t e n c e a m a n u s c r i p t c o p y of t h e t w e n t y - t w o q u e s t i o n s , w i t h r e p l i e s , a d d r e s s e d b y H e n r y O l d e n b u r g , S e c r e t a r y of t h e S o c i e t y , t o C a p t a i n Z e c h a r i a h G i l l a m a f te r h e h a d r e t u r n e d from a voyage in to Hudson Bay in 1668-69 . Employees of t h e Company who r e s i d e d a t o n e o r o t h e r of t h e p o s t s e s t a b l i s h e d o n t h e s h o r e s of The Bay n a t u r a l l y i n c l u d e d refer- e n c e s t o t h e t e r r a i n a r o u n d t h e n . I n t h e P r o c e e d i n g s of t h e F i r s t C o n f e r e n c e , y o u w i l l f i n d some e x t r a c t s f r o m t h e r e c o r d s compiled by James Robson and James Isham, f i r s t p u b l i s h e d i n 1 7 5 2 a n d 1 7 6 0 r e s p e c - t i v e l y ( L e g g e t 1 9 6 3 ) . I have b rough t w i t h m e a photocopy o f a n even ear l ier r e c o r d , e x h i b i t i n g it now so t h a t my more c r i t i ca l f r i e n d s c a n n o t w r i t e t h i s off a s j u s t a n o t h e r of " L e g g e t ' s T a l l stories".

C a p t a i n C h r i s t o p h e r M i d d l e t o n was o n e of t h e most able of t h e C o m p a n y ' s e a r l y s e r v a n t s . T h e R o y a l S o c i e t y p u b l i s h e d i n 1731 a t a b l e of h i s m e t e o r o l o g i c a l a n d m a g n e t i c o b s e r v a t i o n s made d u r i n g n i n e voyages into Hudson Bay. H e w a s e l e c t e d a Fellow o f t h e S o c i e t y i n 1 7 3 7 . I n t h e P h i l o s o p h i c a l T r a n s a c t i o n s of t h e S o c i e t y for 1 7 4 2 t h e r e w a s p u b l i s h e d a r e p o r t w h i c h h e h a d p r e p a r e d a b o u t h i s r e s i d e n c e a t For t P r i n c e of Wal.es d u r i n g t h e w i n t e r of 1741-1742 (Middleton 1 7 4 2 ) . Here are a f e w e x t r a c t s :

" A l l t h e Water w e u s e f o r C o o k i n g , Brewing e t c . , is m e l t e d Snow and Ice; no Sp r ing i s y e t f o u n d f ree from f r e e z i n g , t h o u g h d u g n e v e r so d e e p down. A l l Wa te r s i n - l and a r e f r o z e n f a s t by t h e B e g i n n i n g o f O c t o b e r , a n d c o n t i n u e so till t h e M i d d l e of May.

The Walls of t h e House w e l i v e i n a re of S t o n e , Two F e e t t h i c k , t h e Windows v e r y small, w i t h t h i c k wooden S h u t t e r s , w h i c h are c l o s e s h u t 18 Hours e v e r y Day i n W i n t e r . T h e r e are Cellars unde r t he House , where in w e pu t ou r Wines , Brandy , s t r o n q Beer, B u t t e r , C h e e s e , e tc . Four Large Fires a x e made i n g r e a t S t o v e s , b u i l t o n p u r p ~ s e , e v e r y Day: A s soon as t h e Wood is b u r n t down t o a Coal, t h e T o p s of t h e Chimneys a re close s t o p p e d w i t h a n I r o n Cover: T h i s k e e p s t h e Heat w i t h i n t h e House (a l though a t t h e same time t h e Smoke makes ou r Heads ake , and i s v e r y of fens ive and unwholsome) ; n o t - w i t h s t a n d i n g w h i c h , i n F o u r o r Five Hours a f t e r t h e F i r e is Out , t h e I n s i d e o f t h e Walls of o u r House and Bedplaces w i l l b e Two o r T h r e e I n c h e s t h i c k w i t h Ice, which i s e v e r y M o r n i n g c u t away w i t h a Ha tche t . Three o r Four times a Day w e make I r o n S h o t o f 2 4 Pounds Weight red-hot , and hang t hem up i n t he Windows of ou r Apar tmen t s . 1 have a good F i r e i n my Room t h e major p a r t of t h e 2 4 Hours, y e t a l l t h i s w i l l n o t p r e s e r v e my Beer, Wine, I n k e tc . from f r e e z i n g . It

And again: "The Rocks which a r e s p l i t b y t h e Frost , are heaved up i n g r e a t H e a p s , l e a v i n g l a r g e C a v i t i e s behind: which I t a k e t o b e c a u s e d by t h e i m p r i s o n e d w a t e r y V a p o u r s , t h a t r e q u i r e more R o o m , when f r o z e n , t h a n t h e y o c c u p y i n t h e i r f l u i d s t a t e . N e i t h e r d o 1 t h i n k it unaccout - able, t h a t t h e Frost s h o u l d be a b l e t o tear up Rocks and Trees,

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a n d s p l i t t h e B e a m s o f o u r H o u s e s , when I c o n s i d e r t h e g r e a t F o r c e a n d E l a s t i c i t y t h e r e o f ." And f i n a l l y , a l t h o u g h t h e t e m p t a t i o n

t o g o o n q u o t i n g from this r e m a r k a b l e r e c o r d i s g r e a t :

"The F r o s t i s n e v e r o u t of t h e Ground, how d e e p w e c a n n o t b e c e r t a i n . We have dug down 1 0 OX 1 2 Feet a n d f o u n d t h e E a r t h h a r d f x o z e n i n t h e Two Summer Months ; and what Mois ture w e f i n d F i v e or S i x Feet aown, i s w h i t e l i k e Ice."

( C a p i t a l i s a t i o n a n a p u n c t u a t i o n are as i n t h e o r i g i n a l . )

Those of you who a x e t a k i n g p a r t i n F i e l d T r i p N o . 4 w i l l be v i s i t i n g C h u r c h i l l . I u n d e r s t a n d t h a t y o u w i l l be v i s i t i n g t h e r u i n s o f F o r t P r i n c e of Wales. You may t h e n b e moved t o reca l l t h e f e a r - some w i n t e r s s p e n t t h e r e b y C a p t a i n M i d d l e t o n a n d o t h e r e a r l y s e r v a n t s of The Company. I u r g e you t o v i s i t also S l o o p ' s Cove a n d t h e r e see, c l e a r l y c h i s e l l e d i n t o a s m o o t h r o c k s u r f a c e , t h e s i m p l e w o r d s "Samuel Hearne Ju ly 1767" . Hearne w a s t h e f irst w h i t e man t o r e a c h t h e a r c t i c coast of Canada by land. On h i s g r e a t j o u r n e y t o the Coppermine River h e was also, a l t h o u g h q u i t e i n c i d e n t a l l y a n d w i t h o u t r e a l i z i n g it t h e f irst w h i t e man t o set f o o t i n t h e w a t e r s h e d of the Mackenz ie River, s e v e n t h r iver o f t h e w o r l d , a n d C a n a d a ' s g r e a t e s t w a t e r w a y . I ts d i s c o v e r y i s L i n k e d s t r a n g e l y w i t h A l a s k a , t o t h e h i s t o r y o f w h i c h w e may now b r i e f l y r e t u r n .

I t i s a s t r a n g e b u t i n t e r e s t i n g c o i n c i d e n c e t h a t i n t h e y e a r 1 8 6 7 , o n l y t h r e e a n d a h a l f m o n t h s a f t e r C a n a d a a c h i e v e d t h e s t a t u s of a s e l f - g o v e r n i n g B r i t i s h Dominion (now an independent D o m i n i o n w i t h i n t h e B r i t i s h Commonwealth of N a t i o n s ) , t h e f l a g of t h e U n i t e d S t a t e s of America s h o u l d h a v e b e e n r a i s e d a t S i t k a , b e t o k e n i n g t h e p u r c h a s e of Alaska from t h e Russ ian Government by ou r n e i g h b o u r c o u n t r y t o t h e s o u t h . T h e p u r c h a s e i n c l u d e d t h a t s t r ang-e - look ing pan -hand le , r each ing 300 miles i n t o B r i t i s h Columbia, so p e c u l i a r a f e a t u r e of t h e g e o g r a p h y o f w e s t e r n N o r t h America. ( P a r e n t h e t i c a l l y , I m i g h t p e r h a p s be p e r m i t t e d t o o b s e r v e , p u r e l y p e r s o n a l l y , t h a t t h e removal of t h e c a p i t a l c i t y of A l a s k a from t h e p a n h a n d l e t o "mainland" Alaska seems t o leave t h e way open for a l o g i c a l r e a d j u s t m e n t of t h i s p a r t of t h e map of N o r t h America) .

I n t h i s t h u m b n a i l s k e t c h o f t h e h i s t o r y of t h e g r e a t s t a t e of A l a s k a , focus of so much pe rmaf ros t work o f t h e U n i t e d S t a t e s , one name h a s so f a r b e e n o m i t t e d , t h a t of C a p t a i n James Cook, R . N . , o n e of t h e world's greatest n a u t i c a l e x p l o r e r s . C a n a d a i s

t h i s y e a r m a k i n g t h e b i c e n t e n a r y of h i s l a n d i n g i n B r i t i s h C o l u m b i a , t w o most a t t r a c t i v e p o s t a g e s t a m p s , still ava i l - able, b e i n g p a r t of t h e m a r k i n g of t h e a n n i v e r s a r y . P r o c e e d i n g o n h i s v o y a g e n o r t h w a r d , i n s e a r c h of t h e N o r t h w e s t P a s s a g e , C a p t a i n Cook a l so s a i l e d a l o n g t h e coast of A l a s k a , m a k i n g h i s u s u a l c a r e f u l r e c o r d of a l l t h a t h e s a w . I n o n e r e s p e c t , h o w e v e r , h e was wrong. When s a i l - i n g across t h e m o u t h o f what t oday i s r i g h t l y called Cook I n l e t , h e t h o u g h t t h a t it w a s t h e mouth of a g r e a t river. James Cook w a s t r a g i c a l l y m u r d e r e d j u s t a f e w months la ter ( i n Hawaii) b u t o t h e r s r e p o r t e d on h i s discoveries and named t h e m y t h i c a l r i ve r "Cook's Great River". T h i s became known i n e a s t e r n C a n a d a a n d led a n o t h e r g r e a t e x p l o r e r t o a t t e m p t t o f i n d it.

T h i s was Alexande r Mackenz ie , t he y o u n g S c o t t i s h f u r t r a d e r who n o t o n l y discovered ( i n 1 7 8 9 ) t h e river t h a t now b e a r s h i s name, b u t who, on an even more r e m a r k a b l e j o u r n e y i n 1 7 9 3 , r e a c h e d t h e P a c i f i c Ocean on 2 2 J u l y , b e c o m i n g t h e f i rs t w h i t e man - a n d i n a l l p r o b a b i l i t y , t h e f i r s t man, - t o cross t h e N o r t h A m e r i c a n c o n t i n e n t from sea t o sea. H e w a s a n a s t u t e observer a n d k e p t e x c e l l e n t r e c o r d s of h i s demanding journeys which w e c a n r e a d t o d a y i n c o m f o r t ( M a c k e n z i e : Lamb 1 9 7 0 ) . H e , too, r emarked on t he p e r e n n i a l l y f r o z e n g r o u n d t o be f o u n d i n no r the rn Canada . On F r i d a y 3 1 J u l y 1 7 8 9 , when r e t u r n i n g u p t h e g r e a t r i v e r a f te r r e a c h i n g t h e t i d a l waters of t h e Arctic Ocean i n t h e de l t a , b u t h a v i n g f a i l ed t o f i n d C o o k ' s Great R i v e r , g r e a t l y t o h i s r e g r e t , h e r e c o r d e d some miles u p s t r e a m of t h e s i t e of Norman Wells t h a t " I n o t h e r Places t h e Bank o f t h e River is h i g h of B l a c k E a r t h a n d S a n d c o n t i n u a l l y t u m b l i n g , i n some p a r t s h e w s a f a c e of so l id Ice, to w i t h i n a foot of t h e Surface . ' ' Two d a y s l a t e r , j u s t a f t e r p a s s i n g t h e m o u t h of t h e Bear River h e r e c o r d e d t h e e x i s t e n c e of b u r n i n g coal b e d s , b u r i e d c o n t i n u a l l y by t h e summer- time slumping o f t h e f r o z e n eastern bank o f t h e River. Those o f us who have had t h e p r i v i l e g e of s a i l i n g u p or down t h e Mackenzie have seen t h e s e same f e a t u r e s t o d a y - t h e " t u m b l i n g b a n k s " , " t h e Ice t o w i t h i n a f o o t of t h e S u r f a c e " , a n d t h e b u r n i n g coal b e d s , a l l j u s t as Mackenzie saw them almost t w o hundred yea r s ago . P a r t i c i p a n t s i n F i e l d T r i p s No. 2 and N o . 3 w i l l see something of t h i s r e m a r k - able river; t h e y w i l l see how l i t t l e it has changed s ince A lexande r Mackenz ie f i r s t s a i l e d down it i n h i s c a n o e .

U n t i l t h e d i s c o v e r y of o i l i n t h e 1 9 2 0 ' s a t what i s now Norman Wells, t h e e n t i r e n o r t h e r n p a r t of the Mackenz ie w a t e r s h e d ( a n d t h e rest of n o r t h e r n C a n a d a , a p a r t o n l y from t h e Yukon) was

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v i r t u a l l y u n t o u c h e d . A few Hudson's Bay Company p o s t s , some i n d e p e n d e n t t r a d e r s , t h e f i r s t s i m p l e o u t p o s t s o f t h e R o y a l Canadian Mounted Pol ice and a small m i l i t a r y s i g n a l s t a t i o n i n t h e M a c k e n z i e Delta a t what i s now A k l a v i k were t h e o n l y s i g n s of t h e w h i t e m a n ' s i n t r u s i o n i n t o t h e d o m a i n of t h e n o r t h e r n I n d i a n s a n d Eskimo, or I n u i t a s t h e y a r e now c a l l e d . The Hudson Bay Railway had been s t a r t e d , t o be comple ted t o t h e p o r t o f C h u r c h i l l i n 1 9 2 9 , b u t t h i s was a l l l o c a t e d i n t h e p rov ince o f Man i toba , even t hough pas s ing over p e r e n n i a l l y f r o z e n g r o u n d fox much o f i t s l e n g t h , a n i n d i c a t i o n of t h e v a s t e x t e n t o f t h e C a n a d i a n N o r t h . E v e n t h e s t a r t o f g o l d m i n i n g a n d t h e m i n i n g o f uranium ore on Great Bear L a k e i n t h e l a t e t h i r t i e s were s u c h l o c a l d e v e l o p m e n t s i n t h e M a c k e n z i e V a l l e y t h a t t h e y h a d l i t t l e e f f e c t on l i f e i n t h e v a l l e y b e y o n d p o i n t - i n g t h e way t o necessa ry improvemen t s i n t r a n s p o r t a t i o n .

When I f i r s t came t o know t h e g r e a t v a l l e y ( i n 1940), s t e r n w h e e l e r wood f i r ed steamers were t h e p r i n c i p a l v e s s e l s o n b o t h t h e u p p e r a n d lower Mackenzie River, f o r t h e t h r e e m o n t h s e a s o n o f open naviga- t i o n . The name " p e r m a f r o s t " h a d n o t y e t been coined by D r . S i emon Mul l e r . Bu t t he phenomenon of p e r e n n i a l l y f r o z e n g r o u n d w a s t h e r e , j u s t t h e s a m e . Courageous p i o n e e r b u i l d i n g t e c h n i q u e s h a d b e e n d e v e l o p e d , n o t a b l y a t Norman Wells. I t w a s t h e i m p e r a t i v e o f t h e S e c o n d W o r l d War t h a t c a u s e d t h e f i r s t major i n t r u s i o n of what w e are p l e a s e d t o c a l l c i v i l i z a t i o n i n t o t h e C a n a d i a n N o r t h . F i r s t came t h e b u i l d i n g of t h e C a n o l P i p e l i n e across t h e mounta ins from Norman Wells t o Whi tehorse . D e f e n c e r a d a r s t a t i o n s f o l l o w e d a n d t h e b u i l d i n g o f t h e series of j o i n t Arc t ic w e a t h e r s t a t i o n s w h o s e c o n t i n u i n g service b e n e f i t s t h e w h o l e w o r l d .

I g i v e t h i s t h u m b n a i l s k e t c h o f t h e open ing up of t h e N o r t h of Canada f o r t h e b e n e f i t of o u r o v e r s e a v i s i t o r s . I t i s a s t o r y f a m i l i a r t o m o s t C a n a d i a n s a l t h o u g h , a l l t o o o f t e n i n o u r p u b l i c d i s c u s s i o n s , t h e f a c t t h a t t h e s o - c a l l e d d e v e l o p m e n t of o u r N o r t h i s s o m e t h i n g t h a t s t a r t e d little more t h a n t h i r t y y e a r s a g o i s f o r g o t t e n . Even a f t e r t h e alarms of w a r h a d d i s - appea red , t he Nor th became once aga in a q u i e t a n d l o n e l y l a n d f o r some y e a r s l o n g e x , e n l i v e n e d o n l y b y a few mining p r o j e c t s . So it was t h a t , when i n 1 9 5 0 we s t a r t e d oux r e s e a r c h i n t o p e r m a f r o s t a n d t h e p r o b l e m s it p r e s e n t s , many r e g a r d e d u s a s c r a z y . C e r t a i n l y n o n e of us associated w i t h t h a t m o d e s t s t a r t c o u l d h a v e f o r e s e e n what w a s t o come i n t h e n e x t q u a r t e r c e n t u r y .

C a n a d a ' s f i r s t n o r t h e r n r e s e a r c h s t a t i o n was a t Norman Wells, located a t f i r s t i n de re l i c t b u i l d i n g s l e f t over from

t h e C a n o l p r o j e c t . We d e c i d e d u p o n t h i s l o c a t i o n b e c a u s e of t h e e x i s t e n c e of t h e s m a l l I m p e r i a l Oil. r e f i n e r y t h e r e , w i t h t h e a s s o c i a t e d small w o r k s h o p s , t h e o n l y s u c h c e n t r e o n . the Mackenzie River . I t is a s p e c i a l p r i v i l e g e t o n i g h t t o pay p u b l i c t r i b u t e , a s w e h a v e o f t e n d o n e p r i v a t e l y , t o t h e r e m a r k a b l e c o o p e r a t i o n a n d a s s i s t a n c e w h i c h w e , i n t h e N a t i o n a l Resea rch Counc i l , r e c e i v e d from " I m p e r i a l O i l " i n s t a r t i n g o u c n o r t h e r n r e s e a r c h work, as i n a l l t h e y e a r s s i n c e t h e n . I t was t h i s g r e a t C a n a d i a n c o r p o r a t i o n , w i t h o t h e r l e a d i n g oil companies , which p i o n e e r e d t h e e x p l o r a t i o n f o r o i l a n d n a t u r a l g a s t h r o u g h o u t t h e lower Mackenzie V a l l e y a n d a d j a c e n t a r c t i c t e r r i t o r y . T h i s w o r k l e d e v e n t u a l l y t o t h e g r a n d c o n c e p t of a Mackenzie Val ley o i l p i p e l i n e , t o c o n v e y t h e s e p r o d u c t s from b o t h t h e Canadian and Alaskan a r c t i c coasts t o t h e m a r k e t s of North America.

W i t h s u b s e q u e n t p o l i t i c a l d e v e l o p - m e n t s , s u r r o u n d i n g t h e s e g r e a t p r o j e c t s w e a r e n o t c o n c e r n e d t o n i g h t . S u f f i c e t o s a y t h a t it is now i m p r o b a b l e t h a t e i t h e r l i n e down t h e M a c k e n z i e V a l l e y w i l l be b u i l t i n t h e immediate f u t u r e . R a r e l y , however, have two such major e n g i n e e r i n g p r o j e c t s b e e n p l a n n e d o n t h e b a s i s of s u c h e x t e n s i v e r e s e a r c h w o r k . T h e t e r r a i n a l o n g a l l p o s s i b l e r o u t e s f o r t h e p i p e l i n e s w a s s t u d i e d i n d e t a i l , from t h e a i r and on t h e g r o u n d , t h i s w o r k e x t e n d i n g a l o n g a c o r r i d o r 1 5 0 0 miles l o n g . O u r v i s i t o r s may g a i n some i d e a o f t h e e x t e n t o f t h e Canadian Nor th , from t h e f a c t t h a t t h e d i s t a n c e from t h i s most n o r t h e r n C a n a d i a n c i t y of Edmonton, so t r u l y known as t h e "Gateway t o t h e N o r t h " , t o t h e a r c t i c coast i s j u s t about t h e same as t h e d i s t a n c e f r o m h e r e across t h e p r a i r i e s , pas t Winnipeg and the Lakehead and over L a k e S u p e r i o r t o S a u l t Ste . Marie: o r , if w e w e n t s o u t h , a s far a s t h e b o r d e r of N e w M e x i c o . T h r e e f u l l scale tes t p i p e - l i n e i n s t a l l a t i o n s were b u i l t i n t h i s vas t a r e a , w i t h a f u r t h e r o n e i n A l a s k a a t P r u d o e B a y . T h e C a n a d i a n i n s t a l l a t i o n s were a t I n u v i k (near t h e a r c t i c c o a s t ) , n e a r t h e S a n s S a u l t R a p i d s a n d a t Norman Wells. A l l were f u l l y o p e r a t i n g o i l o r g a s p i p e l i n e s a n d t h e y y i e l d e d i n v a l u a b l e a n d u n i q u e i n f o r m a t i o n .

Nor were t h e e n v i r o n m e n t a n d t h e f i s h and w i ld l i f e of t h e N o r t h n e g l e c t e d . E x t e n s i v e b i o l o g i c a l r e s e a r c h was a l so c a r s i e d o u t i n a l l t h e areas th rough wh ich t h e p i p e l i n e s m i g h t b e e x p e c t e d t o r u n . I can reca l l so w e l l t h a t when, i n 1 9 7 2 , t h i s work was f i r s t d e s c r i b e d i n p u b l i c , it w a s r e m a r k e d t h a t t h i s w a s p r o b a b l y t h e f i r s t time i n h i s t o r y t h a t over $3 m i l l i o n h a d b e e n s p e n t o n f u n d a m e n t a l f i e l d b i o l o g i c a l r e s e a r c h f o x a g r e a t e n g i n e e r i n g p r o j e c t ( L e g g e t a n d MacFarlane 19721. Mention of t h i s f i g u r e

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l e a d s m e t o s a y t h a t , a l t h o u g h I h a v e n e v e r s e e n a n y p u b l i s h e d estimate of t h e t o t a l e x p e n d i t u r e o n t h i s t r e m e n d o u s r e s e a r c h e f f o r t - almost a l l of it i n " p e r m a f r o s t c o u n t r y " - s u c h f i g u r e s as have been p u b l i s h e d s u g g e s t t h a t it must have been s o m e t h i n g l i k e $50 m i l l i o n , i f n o t i n d e e d more t h a n t h i s .

From t h e s t a r t , and as is h a p p i l y a common f e a t u r e of t h e C a n a d i a n way of d o i n g t h i n g s , i n d u s t r y w o r k e d c l o s e l y w i t h i n t e r - e s t e d D e p a r t m e n t s of the Government o f C a n a d a , w i t h t h e N a t i o n a l R e s e a r c h C o u n c i l a n d w i t h u n i v e r s i t i e s . T h a t t h i s i s no i d l e s t a t e m e n t w a s shown by t h e f a c t t h a t , w h i l e t h i s w i d e s p r e a d r e s e a r c h e f f o r t w a s u n d e r w a y , t h e r e was h e l d i n O t t a w a a p u b l i c c o n f e r e n c e a t w h i c h e x c e l l e n t p r o g r e s s r e p o r t s were p r e s e n t e d o n a l l major p a r t s of t h e work t hen go ing on i n t he Mackenz ie Va l l ey . Organ ized by t he Associate Committee on Geo techn ica l Resea rch of t h e N a t i o n a l R e s e a r c h C o u n c i l o f C a n a d a , t h e C o n f e r e n c e a t t r a c t e d w e l l over 500 p a r t i c i - p a n t s . I n view of w h a t h a s h a p p e n e d s i n c e , t h e P r o c e e d i n g s o f t h e C o n f e r e n c e h a v e a l r eady a s sumed some h i s t o r i c v a l u e : a few c o p i e s are still a v a i l a b l e . E s p e c i a l l y welcome was t h e p r e s e n c e of M r . Shagen S. Dongaryan , Deputy Minis te r of t h e M i n i s t r y of t h e O i l I n d u s t r y of t h e S o v i e t Union who s h a r e d w i t h t h e m e e t i n g some of t h e e x p e r i e n c e of h i s M i n i s t r y , i n k e e p i n g w i t h t h e close l i a i s o n w i t h t h e U.S.S.R. t h a t h a s c h a r a c t e r i z e d C a n a d i a n p e r m a f r o s t r e s e a r c h from i t s beg inn ings (Legge t and McFar l ane 1972) .

I n d u s t r y was r e s p o n s i b l e f o r t h e o v e r - a l l p l a n n i n g , d i r e c t i o n a n d f i n a n c i n g of t h e c o m b i n e d e f f o r t b u t it is good t o t h i n k t h a t all a v a i l a b l e k n o w l e d g e i n t h i s c o u n t r y w a s m a r s h a l l e d t o g i v e t h e best p o s s i b l e r e s u l t s f o r t h e a n t i c i p a t e d d e s i g n a n d c o n s t r u c t i o n of t h e p i p e l i n e s , c o n s i s - t e n t w i t h d u e p r o t e c t i o n o f t h e e n v i r o n m e n t and of t h e f i s h a n d w i l d l i f e i n a l l a f f e c t e d areas. Some r e s e a r c h p r o j e c t s i n i t i a t e d a t t h e time o f t h e p i p e l i n e s t u d i e s are con- t i n u i n g t o d a y : i n d u e c o u r s e , w e may e x p e c t t o see t h e r e s u l t s o b t a i n e d p u b l i s h e d f o r p u b l i c b e n e f i t . Much h a s a l r e a d y b e e n p u b l i s h e d , w i t h t h e r e a d y a g r e e m e n t of t h e i n d u s t r i a l s p o n s o r s . Some o f t h e r e s u l t s o b t a i n e d n a t u r a l l y h a v e a p r o p r i e t o r y v a l u e a n d m u s t b e r e t a i n e d as c o n f i d e n t i a l t o t h e s p o n s o r s u n t i l s u c h t i m e as t h e i r p r i v a t e v a l u e i s m i n i m a l . D e s p i t e t h i s v e r y n e c e s s a r y a n d u n d e r s t a n d a b l e l i m i t a t i o n , I have a f e e l i n g t h a t t h e r e s t i l l r e m a i n s a n apprec i ab le amoun t of i n f o r m a t i o n r e s u l t i n g f r o m t h i s g r e a t c o o p e r a t i v e e f f o r t of no s p e c i a l p r o p r i e t o r y v a l u e b u t of g r e a t s c i e n t i f i c i m p o r t a n c e t h a t h a s n o t y e t b e e n p u b l i s h e d . 1 know well t h a t e x c e l l e n t summary r e p o r t s h a v e b e e n p r e p a r e d w i t h c o p i e s p l a c e d i n k e y C a n a d i a n o f f i c e s - b u t t h i s i s n o t p u b l i c a t i o n . Some of t h e

f i n a l r e p o r t s h a v e b e e n p l a c e d i n l ibraries for c o n s u l t a t i o n - b u t , a g a i n , t h i s i s n o t p u b l i c a t i o n .

T h e w o r l d - w i d e i n t e r e s t t o d a y i n p e r m a f r o s t t h a t is so w e l l d e m o n s t r a t e d b y t h e a t t e n d a n c e a t t h i s C o n f e r e n c e s u g g e s t s t o m e t h a t , b e f o r e memories of t h e M a c k e n z i e V a l l e y P i p e l i n e R e s e a r c h e n t e r p r i s e b e g i n t o f a d e , t h o s e i n i n d u s t r y r e s p o n s i b l e f o r t h e s a f e k e e p i n g of t h e r e c o r d s and t h e t e r m i n a t i o n of t h i s g i g a n t i c e f f o r t would per form another p u b l i c service of g r e a t v a l u e i f t h e y w o u l d t a k e a n o t h e r Look a t t h e r e c o r d s t h e y h a v e to see which might now be released a n d p r e p a r e d f o r p u b l i c a t i o n , w i t h n o loss or d e t r i m e n t t o t h e i r r e s p e c t i v e c o m p a n i e s . I t wou ld have t he c h a r a c t e r of a s a l v a g e o p e r a t i o n , a d m i t t e d l y , b u t i f a l l t h e p a p e r s from t h e M a c k e n z i e V a l l e y p e r m a f r o s t r e s e a r c h p r o j e c t , a l r e a d y p u b l i s h e d and y e t t o be p u b l i s h e d ( I hope) were t o b e g a t h e r e d t o g e t h e r i n a series of v o l u m e s , t h e world would be t h e b e n e f i c i a r y a n d t h e series w o u l d c o n s t i t u t e a w o r t h y r e c o r d of e n l i g h t e n e d i n d u s t r i a l c o o p e r a t i v e r e s e a r c h t h a t would be, i n some r e s p e c t s , u n i q u e .

A l l of u s know t h a t p u b l i c a t i o n is o n l y " h a l f t h e b a t t l e " o f g e t t i n g t h e r e s u l t s of e v e n t h e best o f r e s e a r c h i n t o use . Those who n e e d t h e i n f o r m a t i o n for work i n t h e N o r t h m u s t b e l e d t o a p p r e c i a t e i t s e x i s t e n c e i n t h e f i r s t p l a c e , t h e n to r e a d it and t hen t o p u t it i n t o u s e . T h i s i s no e a s y t a s k . I a m s u x e t h a t t h i s t r a n s f e r o f r e s e a r c h i n f o r m a t i o n i n t o a c t u a l u s e i s a worldwide problem. I t i s c e r t a i n l y a n a c u t e p r o b l e m i n C a n a d a . We have had a l l too many examples of p e o p l e going i n t o C a n a d i a n N o r t h a n d " r e d i s c o v e r - i n g t h e w h e e l " (as it is s a i d ) , u n f o r t u n - a t e l y o f t e n b y m a k i n g m i s t a k e s w h i c h i n some cases were i r r e m e d i a l , so f r a g i l e i s much of t h e p e r m a f r o s t t e r r a i n . T h a t t h i s i s n o t j u s t a d i s m a l p e r s o n a l view is shown by t h i s s t a t e m e n t w h i c h came unanimously from a g r o u p of Canadian n o r t h e r n e x p e r t s , m e e t i n g j u s t f i v e y e a r s ago :

" T h e G r o u p u r g e s t h a t p r e q u a l i f i - c a t i o n o f a l l d e s i g n e r s o f p u b l i c l y f i n a n c e d b u i l d i n g s a n d s t r u c t u r e s f o r t h e N o r t h a n d o f a l l c o n t r a c t o r s f o r p u b l i c l y f i n a n c e d n o r t h e r n w o r k , be mandatory." (Greenaway 1 9 7 3 ) .

T h i s s t r o n g s t a t e m e n t i s i n t h e p u b l i c r e c o r d : it s h o u l d p r o v i d e an a b s o l u t e g u i d e l i n e f o r t h e c o n d u c t of a l l govern- m e n t a l w o r k i n o u r n o r t h e r n r e g i o n s . I f e e l s u r e t h a t similar l i m i t a t i o n s , t o e n s u r e t h e b e s t p o s s i b l e w o r k i n n o r t h e r n r e g i o n s , are f o l l o w e d i n t h e U.S.S.R. and t h e P.R.C.

229

T h i s desirable r e q u i r e m e n t s u r e l y p l a c e s a v e r y s p e c i a l r e s p o n s i b i l i t y u p o n a l l o f us who know t h e n o r t h e r n r e g i o n s of o u r c o u n t r i e s - of A l a s k a , t h e U . S . S . R . , China and Canada - t o do a l l i n o u r power t o see t h a t no work i s d o n e t h e r e e x c e p t o n t h e b a s i s of t h e best i n f o r m a t i o n ava i l - able. But I want t o s u g g e s t t o y o u , i n c o n c l u s i o n , a n e v e n g r e a t e r r e s p o n s i b i l i t y t h a t rests u p o n o u r s h o u l d e r s as p r o f e s - s i o n a l men and women who know t h e p r o b l e m s c a u s e d b y d i s t u r b a n c e o f s u r f a c e v e g e t a t i o n

Legget , R.F. 1965 . P e r m a f r o s t i n N o r t h America; i n Proc. P e r m a f r o s t I n t . C o n f . , 1963, N a t . Acad. S c i . a n d N a t . R e s . Counc i l , Wash ing ton , D.C. ( see pp. 2-71.

Leqqet , R . F . and Z.C. MacFarlane ( E d s . ) . i 972 . P roceed ings of t h e C a n a d i a n N o r t h e r n P i p e l i n e R e s e a r c h C o n f e r e n c e (Feb . 1972) . Na t iona l Resea rch Counc i l (NRC NO. 12498) , 331 pp. , Ottawa.

M i d d l e t o n , C . 1742. The Effects o f Cold t o g e t h e r w i t h O b s e r v a t i o n s ........ a t P r i n c e o f Wales's F o r t u p o n C h u r c h i l l

and soils i n r e g i o n s u n d e r l a i n b y p e r m a - River i n Audson's Bay, North America; frost . P h i l . T r a n s . R o y a l S O C . , pp. 157-171,

London. Is it no t oux bounden du ty t o speak S t ea rns , R .P . 1 9 4 5 . The Royal S o c i e t y

o u t a g a i n s t a n d a c t i v e l y o p p o s e a n y d i s t u r - a n d t h e Company, The Beaver, O u t f i t 276 b a n c e of o u r f r a g i l e n o r t h e r n t e r r a i n s pp. 98-113, June 1945, Winnipeg. which i s n o t a b s o l u t e l y e s s e n t i a l , SO as T s y t o v i c h , N.A. 1965 . Pe rmaf ros t i n t h e t o p r e s e r v e fo r t h e f u t u r e as much a s u . S . S . R . ; i n P r o c . P e r m a f r o s t I n t . C o n f . p o s s i b l e of t h e w i l d l a n d s o f t h e N o r t h ? 1 9 6 3 , Nat. Acad. Sci . and N a t . R e s . , T r a n s p o r t a t i o n , f o r e x a m p l e , s h o u l d s u r e l y be by water t o t h e e x t e n t t h a t i s p o s s i b l e

Counc i l , Wash ing ton , D.C. (see p. 8 ) .

and o the rwise by a i r ; r a i l w a y s s h o u l d b e c o n s t r u c t e d o n l y when economics and no r the rn welfare combine t o make them e s s e n t i a l ; a n d r o a d s o n l y a s a l a s t resort, and when n o t o n l y e c o n o m i c s b u t d e m o n s t r a t e d human n e e d s make t h e i r b u i l d i n g u n a v o i d a b l e . A l l who know t h e N o r t h know a l so t h a t r o a d c o n - s t r u c t i o n a n d u s e c a n w r e c k moce havoc t o t h e n o r t h e r n e n v i r o n m e n t t h a n a n y o t h e r work of man.

W e a re , i n a way, t h e T r u s t e e s of t h e N o r t h , w i t h o u r s p e c i a l k n o w l e d g e of perma- f r o s t a n d t h e h a z a r d s w h i c h i t s d i s t u r b a n c e c a n cause. We must see t o it t h a t o u r n o r t h e r n terr i tor ies - Canadian , Alaskan , S o v i e t a n d C h i n e s e - are p r e s e r v e d i n as n a t u r a l a s ta te a s p o s s i b l e , c o n s i s t e n t w i t h c o n t r o l l e d d e v e l o p m e n t of n a t u r a l r e s o u r c e s . I u r g e you t o l e a v e t h i s f i n e C o n f e r e n c e n o t o n l y i n s p i r e d by t h e new knowledge you have ga ined , no t on ly e n r i c h e d b y new f r i e n d s h i p s , b u t f i r m l y r e s o l v e d n e v e r t o f o r g e t y o u r own p e r s o n a l r e s p o n s i b i l i t y as a c o n s e r v a t o r of o u r n o r t h e r n l a n d s .

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Anon. 1978. S tudy begins of baby mammoth; N a t u r e , v . 273 p. 485, 1 5 June 1978 London.

B a n c r o f t , H . H . 1886 . H i s to ry of A l a s k a , 774 pp. , S a n F r a n c i s c o .

B e a g l e h o l e , J . T . 1974 . The L i f e o f C a p t a i n James Cook, 700 pp, , Black, London.

Greenaway, K . ( E d . ) 1973 . Sc i ence and t he North, 287 pp., O t t a w a .

Haswell, C . K . 1 9 6 9 . Thames Cable Tunnel ; P r o c . I n s t . C i v i l Engs. , v . 4 4 , p . 323 , December 1969, London.

Lamb, W. Kaye ( E d . ) 1970. The Journa ls and L e t t e r s of S i r A lexande r Mackenz ie , 551 pp., Cambridge.

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OPENING PLENARY S E S S I O N Monday, 1 0 J u l y , 1 9 7 8

D r . R . J . E . B r o w n : L a d i e s a n d G e n t l e m e n . I s h o u l d l i k e t o b e g i n t h e T h i r d I n t e r - n a t i o n a l C o n f e r e n c e On P e r m a f r o s t b y w e l c o m i n g a l l d e l e g a t e s , a c c o m p a n y i n g p e r s o n s a n d o t h e r s c o n n e c t e d w i t h t h e C o n f e r e n c e t o t h e p r o c e e d i n g s t h i s m o r n i n g , My name i s Roger Brown. I am t h e C h a i r - man o f t h e O r g a n i z i n g C o m m i t t e e f o r t h e C o n f e r e n c e . I w i l l now i n t r o d u c e t h e o t h e r p e r s o n s o n t h e p l a t f o r m who w i l l s p e a k in t h i s o p e n i n g s e s s i o n . Dr. L.W. G o l d , A s s i s t a n t D i r e c t o r o f t h e D i v i s i o n o f R u i l d i n g R e s e a r c h , N a t i o n a l R e s e a r c h C o u n c i l o f C a n a d a , i s t h e C h a i . r - man o f t h e N R C A s s o c i a t e C o m m i r t e e on G e o t e c h n i c a l R e s e a r c h . T h i s i s t h e p a r e n t b o d y o f t h e O r g a n i z i n g C o m m l t t e e f o r t h i s C o n f e r e n c e . D r . T . L . PGwG i s t h e l e a d e r o f t h e d e l e g a t i o n f r o m t h e U n i t e d S t a t e s . P r o f e s s o r P . I . M e l n i k o v i s t h e l e a d e r o f t h e d e l e g a t i o n f r o m t h e S o v i e t U n i o n .

A s you know w e w i l l b e i n E d m o n t o n f o r f o u r d a y s f o r t h e t e c h n i c a l s e s s i o n s i n c l u d i n g t h e p r e s e n t a t i o n s o f t h e s p e c i a l r e v i e w p a p e r s . A t t h e e n d o f t h e s e m e e t i n g s o n T h u r s d a y a f t e r n o o n , t h e r e w i l l b e a c l o s i n g p l e n a r y s e s s i o n a t w h i c h s o m e q u e s t i o n s w i l l b e r a i s e d . One w i l l b e a b o u t t h e p o s s i b i l i t y o f f o r m i n g s o m e s o r t o f i n t e r n a t i . o n a 1 p e r m a f r o s t a s s o c - i a t i o n a m o n g t h e v a r i o u s i n t e r e s t e d c o u n t r i e s . A n o t h e r w i l l c o n c e r n t h e F o u r t h I n t e r n a t i o n a l C o n f e r e n c e On P e r m a f r o s t .

A p r i n c i p a l t a s k o f t h e C h a i r m a n o f t h e C o n f e r e n c e i s t o a c k n o w l e d g e t h e a s s i s t a n c e o f t h e many p e o p l e who a r e i n v o l v e d i n i t s o r g a n i z a t i o n a n d a r r a n g e - m e n t s ; ' F i r s t , I w i s h t o t h a n k a l l o f y o u f o r a t t e n d l n g . In t h e s e d a y s o f h i g h t r a v e l c o s t s a n d c o n f l i c t i n g c o m m i t m e n t s i t i s d i f f i c u l t t o t r a v e l t o t h e many c o n f e r e n c e s t h a t a r e b e i n g h e l d . T h e C o n f e r e n c e o r g a n i z e r s a r e g r a t i f i e d b y t h e a t t e n d a n c e w h i c h i s n e a r l y 5 0 0 f r o m a b o u t E u r o p e

I g r o u p s much t o f t h e

5 c o u n t r i e s i n N o r t h A m e r i c a , a n d A s i a .

s h o u l d l i k e t o m e n t i o n v a r i o u s a n d i n d i v i d u a l s who c o n t r i b u t e d s o m e a n d e f f o r t t o t h e o r g a n i z a t i o n C o n f e r e n c e . One o f t h e m o s t n o t a b l e

i s t h e L o c a l A r r a n g e m e n t s S u b c o m m i t t e e o f t h e O r g a n i z i n g C o m m i t t e e c h a i r e d b y Dr. J . I . C l a r k . T h e y o r g a n i z e d a1.1 o f t h e l o c a l a r r a n g e m e n t s a n d f u n c t i o n s a n d we a r e g r a t e f u l t o h i m a n d h i s s u b c o m - m i t t e e f o r t h i s v a l u a b l e a s s i s t a n c e , T h e v e r y f i n e p r o g r a m f o r a c c o m p a n y i n g p e r s o n s i s c h a i r e d b y Mrs. M o r g e n s t e r n a n d we g r e a t l y a p p r e c i a t e h e r e f f o r t s . D r . N . R . M o r g e n s t e r n i s c h a i r m a n o f t h e s u b c o m m i t t e e w h i c h o r g a n i z e d t h e t e c h - n i c a l p r o g r a m . T h e e x c e l l e n t V o l u m e I o f t h e P r o c e e d i n g s r e s u l t e d f r o m t h e w o r k o f h i s g r o u p a n d t h e s u b c o m m i t t e e o n p u b l i c a t i o n s c h a i r e d b y Dr. W . O . K u p s c h . 'c t h i n k y o u w i l l a g r e e t h a t t h i s i s a n e x c . e l . l e n t p i e c e o f w o r k a n d we a p p r e c i a t e t h e i r e f f o r t s v e r y m u c h . T h e c o o r d i n a t o r f o r o r g a n i z a t i o n o f t h e f i e l d t r i p s i s D r , D . E . K e r f o o t w h o s e a s s i s t a n c e i s g r a t e f u l l y n o t e d . I s h o u l d l i k e t o t h a n k Dr. T . . W . G o l d f o r t h e v e r y a c t i v e s u p p o r t w h i c h h e h a s g i v e n t o t h e w o r k o f t h e O r g a n i z i n g C o m m i t t e e . I w i s h to make s p e c i a l m e n t i o n o f my c o l l e a g u e a n d c l o s e f r i e n d , Mr. G . H . J o h n s t o n , whom many of y o u k n o w , a n d w i t h whom I h a v e w o r k e d f o r m a n y y e a r s . He a s s i s t e d m e i n m o r e w a y s t h a n I c a n r e c o u n t t o y o u a n d I s h o u l d l i k e t o a c k n o w l e d g e p u b l i c l y t h e g r e a t h e l p w h i c h h e g a v e m e . I w o u l d b e remiss i f I d i d n o t m e n t i o n t h e w o r k o f t h e s t a € f i n t h e C o n f e r e n c e S e r v i c e s O f f i c e a t t h e N a t i o n a l R e s e a r c h C o u n c i l . o f C a n a d a , O t t a w a , h e a d e d b y M r . K . C h a r b o n n e a u . You s a w h i s n a m e a n d t h a t o f f i c e m e n t i o n e d in t h e B u l l e - r i n s o f t h e C o n f e r e n c e . T h e y a r e w o r k i n g now a t t h e r e g i s t r a t i o n d e s k w h e r e t h e y s p e n d l o n g h o u r s . T h i s v i t a l s e r v i c e now a n d t h e m a n y m o n t h s o f e f f o r t p r i o r t o t h e C o n f e r e n c e i s g r a t e f u l l y a c k n o w l e d g e d .

T h e C o n f e r e n c e h a s b e e n s u p p o r t e d b y q u i t e a n u m b e r o f d o n a t i o n s . T h e N a t i o n a l R e s e a r c h C o u n c i l o f C a n a d a i t - s e l f b e i n g t h e s p o n s o r i n g a g e n c y h a s g i v e n a g r e a t d e a l o f h e l p , b o t h m o n e t a r y a n d i n o t h e r w a y s , S i x C a n a d i a n f e d e r a l d e p a r t m e n t s g a v e f i n a n c i a l c o n t r i b u t i o n s : E n e r g y , M i n e s a n d R e s o u r c e s ; F i s h e r i e s a n d E n v i r o n m e n t ; I n d i a n a n d N o r t h e r n A f f a i r s ; N a t i o n a l D e f e n s e ; P u b l i c W o r k s ; a n d T r a n s p o r t . We a l s o r e c e i v e d

d o n a t i o n s f r o m i n d u s t r i a l f i r m s , m o s t l y i n w e s t e r n C a n a d a , t o whom w e a r e m o s t g r a t e f u l . T h e P r o v i n c e o f A l b e r t a h a s b e e n v e r y g e n e r o u s w i t h i t s f i n a n c i a l a s s i s t a n c e , A r e p r e s e n t a t i v e o f t h e p r o v i n c i a l g o v e r n m e n t w i l l a d d r e s s o u r b a n q u e t W e d n e s d a y e v e n i n g . T h e C i t y o f E d m o n t o n h a s a l s o c o n t r i b u t e d a n d t h e Mayor w i l l s p e a k t o o u r l u n c h e o n t o m o r r o w . We a r e v e r y f o r t u n a t e t o b e h e r e i n t h i s f i n e C i t y o f E d m o n t o n i n t h e P r o v i n c e o f A l b e r t a , a n d we a p p r e c i a t e t h e h o s p i t a l - i t y a n d f r i e n d l y a t m o s p h e r e t h a t e x i s t s h e r e . W i t h t h e s e c o m m e n t s I now d e c l a r e t h e T h i r d I n t e r n a t i o n a l C o n f e r e n c e On P e r m a f r o s t t o b e o f f i c i a l l y o p e n e d . I w o u l d l i k e t o c a l l on D r . G o l d t o s a y a f e w w o r d s . T h a n k y o u .

D r . L .W. G o l d : Mr. C h a i r m a n , H o n o u r a b l e D e l e g a t e s , L a d i e s a n d G e n t l e m e n . I t i s b o t h a n h o n o u r a n d a g r e a t p l e a s u r e f o r me t o w e l c o m e y o u on b e h a l f o f D r . S c h n e i d e r , t h e P r e s i d e n t o f t h e N a t i o n a l R e s e a r c h C o u n c i l o f C a n a d a , a n d t o b r i n g y o u h i s g r e e t i n g s a n d b e s t w i s h e s for a s u c c e s s f u l C o n f e r e n c e . D r . S c h n e i d e r w o u l d h a v e l i k e d v e r y m u c h t o b r i n g t h e s e w o r d s t o y o u p e r s o n a l l y , b u t h e i s t h e c h a i r m a n o f t h e o r g a n i z i n g c o m m i t t e e f o r a n o t h e r i n t e r n a t i o n a l c o n f e r e n c e t h a t i s b e i n g h e l d i n T o r o n t o t h i s w e e k . I a l s o w a n t t o w e l c o m e y o u o n b e h a l f o f t h e A s s o c i a t e C o m m i t t e e On G e o t e c h n i c a l R e s e a r c h o f t h e N a t i o n a l R e s e a r c h C o u n c i l o f C a n a d a . I w o u l d l i k e t o s a y a f e w w o r d s a b o u t t h i s C o m m i t t e e , T h e A s s o c i a t e C o m m i t t e e i s o n e o f t h e C a n a d i a n n a t i o n a l c o m m i t t e e s e s t a b l i s h e d b y t h e N a t i o n a l R e s e a r c h C o u n c i l t o c o n s i d e r p r o b l e m s o f c o u n t r y - w i d e c o n c e r n , I t was f o r m e d in 1 9 4 5 t o c o o r d i n a t e a n d s t i m u l a t e r e s e a r c h o n t h e e n g i n e e r i n g a n d p h y s i c a l a s p e c t s o f t h e t e r r a i n o f C a n a d a . B e c a u s e a b o u t o n e - h a l f o f o u r c o u n t r y i s u n d e r l a i n b y p e r m a f r o s t , i t w a s n a t u r a l t h a t t h e C o m m i t t e e s h o u l d p a y p a r t i c u l a r a t t e n t i o n t o t h i s s u b j e c t . I n 1 9 5 8 i t s p o n s o r e d t h e f i r s t c o n f e r e n c e h e l d in C a n a d a d e v o t e d s o l e l y t o t h e s u b j e c t o f p e r m a f r o s t . T h a t c o n f e r e n c e c l e a r l y s h o w e d t h e g r o w i n g i n t e r e s t a n d c o n c e r n t h a t was d e v e l o p i n g i n C a n a d a on t h o s e q u e s t i o n s . I n r e s p o n s e t o t h i s t h e A s s o c i a t e C o m m i t t e e e s t a b l i s h e d i n 1 9 6 0 a S u b c o m m i t t e e o n P e r m a f r o s t . T h a t p a r t i c u l a r S u b c o m m i t t e e h a s b e e n v e r y e f f e c t i v e i n s t i m u l a t i n g r e s e a r c h o n b a s i c a s p e c r s o f p e r m a f r o s t a n d r e l a t e d e n g i n e e r i n g a c t i v i t i e s , a n d i n d e v e l o p i n g c o m m u n i c a t i o n a m o n g i n d i v i d u a l s i n u n i - v e r s i t i e s , i n d u s t r y a n d g o v e r n m e n t t h a t h a v e a n i n t e r e s t i n t h i s s u b j e c t . I t h a s p l a y e d a l e a d i n g r o l e i n t h e d e v e l o p m e n t o f t h e k n o w l e d g e a n d c a p a b i l i t y c o n c e r n i n g t h i s p a r t i c u l a r l y c h a l l e n g i n g g r o u n d con- d i t i o n , p r i m a r i l y t h r o u g h t h e s p o n s o r i n g o f seminars c o v e r i n g a b r o a d r a n g e o f t o p i c s . T h e p r o c e e d i n g s o f t h e s e seminars

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h a v e b e e n m a d e a v a i l a b l e t h r o u g h t h e p u b l i c a t i o n s s e r i e s o f t h e A s s o c i a t e C o m m i t t e e .

N o t o n l y h a s t h i s S u b c o m m i t t e e b e e n a c t i v e w i t h i n t h e c o u n t r y , b u t i t h a s a l s o p l a y e d a s t r o n g r o l e f o r C a n a d a i n t e r - n a t i o n a l l y . I t a c t e d a s t h e c o o r d i n a t i n g c o m m i t t e e f o r C a n a d i a n p a r t i c i p a t i o n i n t h e F i r s t I n t e r n a t i o n a l C o n f e r e n c e On P e r m a f r o s t h e l d a t P u r d u e U n i v e r s i t y i n t h e U n i t e d S t a t e s i n 1 9 6 3 . I t c a r r i e d o u t t h e same t a s k f o r t h e S e c o n d T n t e r - n a t i o n a l C o n f e r e n c e On P e r m a f r o s t h e l d a t Y a k u t s k i n t h e U . S . S . B . i n 1 9 7 3 . T h e c h a i r m a n a t t h a t t ime, P r o f e s s o r J . R . M a c k a y , h e a d e d t h e C a n a d i a n d e l e g a t i o n t o t h e S o v i e t U n i o n a n d i s s u e d t h e r e t h e i n v i t a t i o n f o r t h e n e x t c o n f e r e n c e t o b e h e l d h e r e i n C a n a d a . U n d e r i t s p r e s e n t c h a i r m a n , Dr. W.O. K u p s c h , t h e S u b c o m m i t t e e u n d e r t o o k f o r t h e A s s o c i a t e C o m m i t t e e t h e t a s k o f p u t t i n g t o g e t h e r t h e O r g a n i z i n g C o m m i t t e e f o r t h i s C o n f e r e n c e . I t h i n k i t i s v e r y f i t t i n g t h a t t h e g u e s t s p e a k e r a t t h e b a n q u e t W e d n e s d a y e v e n i n g i s D r . R . F . L e g g e t . He i s t h e i n d i v i d u a l r e s p o n - s i b l e f o r t h e e s t a b l i s h m e n t o f t h e A s s o c i a t e C o m m i t t e e a n d g u i d e d i t f o r m o r e t h a n 2 0 y e a r s . I t was l a r g e l y d u e t o h i s f o r e s i g h t a n d i n i t i a t i v e t h a t t h e A s s o c i a t e C o m m i t t e e h a s h a d t h e o p p o r - t u n i t y o f p a r t i c i p a t i n g i n c o n t r i - b u t i n g t o t h e g r o w t h o f p e r m a f r o s t r e s e a r c h a n d e n g i n e e r i n g in C a n a d a a n d t h e p r i v i l e g e o f p r o v i d i n g t h e f o c a l p o i n t f o r t h e o r g a n i z a t i o n o f t h i s Con- f e r e n c e . An i m p r e s s i v e n u m b e r o f p a p e r s o f h i g h q u a l i t y h a s b e e n s u b m i t t e d t o t h i s m e e t i n g . I know t h e s e s s i o n s a r e g o i n g t o b e o f g r e a t i n t e r e s t a n d t h e i n f o r m a t i o n p r e s e n t e d o f l a s t i n g v a l u e . On b e h a l f o f t h e A s s o c i a t e C o m m i t t e e , 1 w a n t t o w i s h y o u e v e r y s u c c e s s i n y o u r d e l i b e r a t i o n s . T h a n k y o u .

D r . R . J . E , B r o w n : T h a n k y o u v e r y m u c h , D r . G o l d . I s h o u l d l i k e t o c a l l on D r . PGwE t o s p e a k o n b e h a l f o f t h e d e l e g a t i o n f r o m t h e U n i t e d S t a t e s .

D r . T . L . PGwP: Mr. C h a i r m a n , D e l e g a t e s , L a d i e s a n d G e n t l e m e n . T h e m e m b e r s o f t h e p e r m a f r o s t c o m m u n i t y i n t h e U n i t e d S t a t e s o f A m e r i c a a r e m o s t p l e a s e d t o p a r t i c i - p a t e i n t h e d e l i b e r a t i o n s h e r e i n Edmon- t o n , a n d in t h e f i e l d e x c u r s i o n s t o b e h e l d l a t e r . We a p p r e c i a t e t h e h o s p i t a l - i t y a n d t h e e x c e l l e n t p l a n n i n g t h a t i s s o e v i d e n t i n t h i s m e e t i n g . We a r e v e r y h a p p y to b e h e r e i n C a n a d a , f o r i t i s i n t h i s c o u n t r y t h a t w e h a v e t h e e a r l i e s t k n o w n r e c o r d o f p e r m a f r o s t o b s e r v a t i o n s i n N o r t h America - o b s e r v a t i o n s m a d e b y e a r l y e x p l o r e r s i n the A r c t i c I s l a n d s m o r e t h a n 4 0 0 y e a r s a g o . Today, C a n a d a i s o n e o f t h e l e a d i n g a r e a s o f p e r a a - f r o s t r e s e a r c h i n t h e w o r l d . We a r e

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happy to have worked closely in permafrost with our northern neighbours for decades. Now, permafrost experts from the United States in academia, industry, state and local. governments a r e here to meet with their international colleagues. We wish to thank Dr. Brown and his staff in providing the opportunity for scientists and engineers from various parts of the world to discuss and extend our knowledge of theoretical and practical problems of perennially and seasonally frozen ground. Thank you.

Dr. R.J.E. Brown: Thank you very much Dr. 1'6~6. I should like now to call upon Professor Melnikov to speak on behalf of the Soviet Union.

Professor F.I. Melnikov: (Text in Russ- ian at end of this session)

Ladies an2 gentlemen, Mr. Chairman, members of the Oraanizating Committee!

Allow me to transmit to you the sincere greetings and best wishes of the Soviet delegation to this Conference and of all. geocryologists of the Soviet Union.

Five years have passed since the successful second Internation Conference On Permafrost which was held in the central region of the cryolithic zone of the USSR in the territory o f ' Yakutiya. The work of the plenary sessions, the interesting and, I darc say, fascinating field trips have left good impressions on the delegates of the previous Conference.

The resolution o f the second Inter- national Conference On Permafrost e x p r e s s e d

ment in permafrost research. )luring the past fi.ve years we have worked on these problems arid have achieved a certain success in fundamental as well a s applied research. The main results oi' these investigations are presented to the Conference in 53 papers and special editions of compilations of articles on various aspects of permafrost research. Soviet permafrost research workers pre- p a r e d a total. of 1 3 2 papers and articles for this Conference. This constitutes a weighty contribution by Soviet scientists towards the work of this Conferencc, T h e large number of papers presented by the Soviet delegation i s indicative of the high level of development of permafrost research in the Soviet Union and constitutes a great contribution to this developing and very important field o f scientific knowledge.

the forcmos-t pro .b l c rns oI' i ' u r t h c r ' develop-

Investigations of the composition, structure, formation conditions, and evolution of cryolithic zones were carried

on and developed. Zonal and regional peculiarities of geographic occurrences of seasonally frozen ground and permafrost were identified, and their thicknesses, temperatures, and interaction with groundwater established. Particular attention was devoted to the study of "Alpine permafrost" in the high mountainous regions o f southern USSR.

Much attention was given to the investigation o f the thermo-physical basis of the processes o f formation and development of cryolithic zones.

Great importance is devoted to the development of scientific foundations and control methods of cryogenic processes i.n the economic development of permafrost regions.

We have worked on the development of new effective methods of permafrost research using modern technological means.

Working out the physical and mathematical foundations of forecasting the progression of cryogenic processes in the arctic regions under development has become the most important problem. One of the crucial problems in permafrost regions under economic development is the protection of the environment.

Due to lack of time I cannot dwell on all the geocryologic research being carried out now. I should mention, however, that all the subjects, singled out in the resolutions of the second International Conference On permafrost are being worked on by Soviet geocryologists.

The published papers and reports presented at this Conference may help to judge the results of' these investigations. About 300 monographs, papers, compilations, articles, and other types of publications, totalling more than 1000 typed. pages, have been published in our country during the past five years. Such a great volume of literature is a vivid indication of the attention devoted to ,the development of permafrost research in our country. The Soviet Union, the USA, and Canada have gigantic areas of permafrost formations. Occurrences of valuable o r e s are con- centrated in such area, and they are being developed at an increasing pace. Economic development of permafrost regions can, however, be realized effectively only if the technological and geocryological changes, dependent on the adopted methods for the development of the territory, have been carried out, and methods for the regional exploitation of natural resources and for the reestablishment of the disturbed natural vegetation worked out.

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Research in the field of environmental protection has increased significantly during the past five years, This is becoming a global problem and all n&tions are devoting particular significance to it. The approach which considers nature to be an extremely complex system in equilibrium, must be given its due importance in our research, The Construction of the Trans- Alaska pipeline is an exemplary case, It is there that the requirements of the environmental protection legislation of the USA are being realized for the first time on a large industrial project. The costs of these measures constitute a high sum, but it is difficult to estimate the material and social price that would have been incurred, had the environment protection measures not been given such a great importance.

Much attention was devoted to geocryological forecasting during the past few years. This is understood to mean a scientific prediction of the direction o f development and of the degree o f change of the geocryological conditions which will take place in the future as a result of natural evolution, or economic development of the territory. The forecasting is b a s e d on investigations which are aimed to discover the laws, o f specific, general, o r regional character, which govern the formation of permafrost conditions and to unveil the meaning of such laws.

The study of the thermal state of the permafrost, its dynamics, its relationship with the climate and deep seated processes, and the development o f the theory of deep freezing of the earth's crust are some of the principal problems in this category. The unstable permafrost occurrences, which have the widest development in Western Siberia, arouse considerable interest. It has been actually confirmed that these are developments separated from the sufacc of deeply occurring permafrost, which is melting at the present time from above and from below, The unstable permafrost contains information on the past glacial p e r i o d . The strictly quantitative nature of the extracted information makes it all the more valuable. These are the first quantitative data on the palaeoclimate which are obtained directly from an analysis of the present day permafrost. It is, so to speak, a window opened into the actual evolution of permafrost during an epoch of abrupt climatic changes. Future work in this area requires a theory of the stable and unstable temperature fields and of the processes of deep freezing of the earth's crust.

We consider the determination of the age of permafrost to be of great importance.

Until recently this age was considered to be of the o r d e r of 40 to 50 thousands of years. A s a result o f our investigations the concept of an uninterrupted existence of permafrost was developed. Data of the permafrost facies analysis of deposits dated by means of palaeon- tological and thermoluminescent methods indicate that the permafrost of Central Yakutia has not thawed for a period longer than 300,000 years, This very important discovery permits u s to reconstruct the palaeoclimate in a new way, and to reassess the formation conditions and the evolution of the earth's permafrost in a different light.

The study o f the hydrology of permafrost has always attracted the attention of Soviet specialists, becauae the complex interaction between groundwater and permafrost is the key to the understanding of permafrost dynamics; while the groundwater itself, which is protected from pollution, is regarded to be a potential source of water supply. In recent years we have conducted investigations of kriopeR* brines, which have negative temperatures. Undoubtedly the mighty pressure horizon, discovered in the northern kriopeg regions, partici- pates in the convective heat exchange may be the source o f the deep cooling of rocks. Kriopegs may complicate mineral mining operations.

In the f ' i e l d of permafrost engineering the introduction of refrigerating devices using seasonally acting fluids attracts the greatest interest. They are based on natural circulation of the refrigerating fluid and are u s e d for controlling the temperature regime of the ground ir. northern construction. Such devices are employed in the Soviet, Union in construction of buildings, linear structures, and earth dams. Research in this direction is extremely promising because of such advantages as high economic efl'icieucy, increased stability of structures, and better feasibility of construction under complex geocryological conditions

""

* - The definition for kriopelr: given in the Russian-English Glossary of Permafrost Terms prepared by V.N. P o p p e and R.J.E. Brown, NRC Technical Memorandum No. 117, Ottawa, April 1976, i s as follows: body of liquid saline water below O O C associatea with permafrost; may also imply ice free permafrost with saline pore water.

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The t a s k s o f t h i s i n t e r n a t i o n a l c o n - f e r e n c e o n p e r m a f r o s t a r e t o e l u c i d a t e r e c e n t r e s e a r c h r e s u l t s , t o c h a r a c t e r i z e t h e s c i e n t i f i c a n d p r a c t i c a l a c h i e v e m e n t s o f t h e p a s t f i v e y e a r s , a n d t o i n d i c a t e t h e d i r e c t i o n f o r f u t u r e d e v e l o p m e n t s i n p e r m a f r o s t r e s e a r c h .

In c o n c l u s i o n I w a n t t o t h a n k t h e O r g a n i z i n g C o m m i t t e e for t h e i n v i t a t i o n t o t h e C o n f e r e n c e a n d f o r t h e h o s p i t a l i t y o f f e r e d t o o u r d e l e g a t i o n ,

D r . R . J . E . Brown: Thank you very much, Professor M e l i n k o v . T h i s c o n c l u d e s t h e o p e n i n g s e s s i o n o f t h e C o n f e r e n c e . We will now proceed d i r e c t l y t u t h e p r e - s e n t a t i o n o f t h e f i r s t r e v i e w p a p e r . T h a n k y o u .

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BblCTYnJIEHME HA OTKPHTMM I11 MEH(,JJYHAPOTJHOR KOHOEPEHIIMM no MEP3JlOTOBEnEHW B KAHAAE

/10 umnff 1978 rana/

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CLOSING PLENARY SESSION T h u r s d a y , 1 3 J u l y , 1 9 7 8

D r . R.J.E. Brown: Welcome t o t h e f i n a l s e s s i o n o f t h e T h i r d I n t e r n a t i o n a l C o n f e r - e n c e On P e r m a f r o s t . We h a v e b e e n m e e t i n g h e r e i n E d m o n t o n f o r t h e p a s t f o u r d a y s t o l i s t e n t o many e x c e l l e n t p a p e r s o n a l l a s p e c t s o f p e r m a f r o s t , a n d now we a r e g a t h e r e d t o g e t h e r f o r s o m e i t e m s o f b u s i - n e s s a n d a f e w c l o s i n g r e m a r k s . I w o u l d l i k e t o t h a n k a l l o f y o u o n b e h a l f o f t h e O r g a n i z i n g C o m m i t t e e f o r a t t e n d i n g t h e C o n f e r e n c e . I am s u r e y o u w i l l a g r e e , t h a t we h a v e h a d f o u r d a y s o f v e r y f r u i t - f u l d i s c u s s i o n w i t h f r i e n d s f r o m many c o u n t r i e s i n v o l v e d i n p e r m a f r o s t w o r k a n d I know t h a t w e l o o k f o r w a r d t o c o n t i n u i n g t h e s e c o n t a c t s i n t h e d a y s a h e a d .

T h e r e a r e s e v e r a l i tems t o b e d i s - c u s s e d i n t h i s s e s s i o n . The f i r s t i s t h e p o s s i b i l i t y o f f o r m i n g s o m e s o r t o f i n t e r n a t i o n a l p e r m a f r o s t a s s o c i a t i o n s i m i l a r t o t h o s e i n o t h e r f i e l d s o f i n t e r e s t . In t h e p a s t , t h e r e h a s b e e n no s u c h g r o u p i n t h i s p a r t i c u l a r f i e l d , p a r t l y b e c a u s e we h a v e h a d o n l y a f e w i n t e r n a t i o n a l c o n f e r e n c e s . F u r t h e r m o r e t h e f i e l d o f p e r m a f r o s t i s e x t r e m e l y v a r i e d a n d i n t e r d i s c i p l i n a r y a n d a t t e m p t s t o j o i n w i t h o n e o r a n o t h e r i n t e r n a t i o n a l o r g a n i z a t i o n h a v e p r o v e n d i f f i c u l t i n t e r m s o f s a t i s f y i n g e v e r y o n e ' s r e q u i r e - m e n t s a n d i n t e r e s t s . E a r l i e r t h i s w e e k t h e h e a d s o f t h e d e l e g a t i o n s o f C a n a d a , U n i t e d S t a t e s , S o v i e t U n i o n a n d t h e P e o p l e ' s R e p u b l i c o f C h i n a h e l d a n i n f o r m a l m e e t i n g a t w h i c h w e d i s c u s s e d t h i s m a t t e r . I t w a s a g r e e d t h a t i t w o u l d b e w o r t h w h i l e t o i n v e s t i g a t e w h a t w o u l d b e i n v o l v e d i n f o r m i n g a n i n t e r n a t i o n a l a s s o c i a t i o n . I t w a s d i s c u s s e d s e v e r a l m o n t h s a g o a t t h e l a s t m e e t i n g o f t h e O r g a n i z i n g Com- m i t t e e f o r t h i s C o n f e r e n c e a n d w e a g r e e d t h a t we w o u l d b e w i l l i n g i n C a n a d a t o e s t a b l i s h a n a d h o c s e c r e t a r i a t t o l o o k i n t o t h e p o s s i b i l i t y o f f o r m i n g s o m e s o r t o f a s s o c i a t i o n . T h e r e a r e d i f f i c u l t p r o - b l e m s ro b e f a c e d s u c h a s d e c i d i n g on t h e s t r u c t u r e o f a n a s s o c i a t i o n , r e l a t i o n s w i t h o t h e r s i m i l a r g r o u p s , r e l a t i o n o f n a t i o n a l c o m m i t t e e s t o a n i n t e r n a t i o n a l a s s o c i a t i o n , e t c . D r . G o l d a n d I a g r e e d t o l o o k i n t o t h i s ma t t e r o n b e h a l f o f t h e o t h e r c o u n t r i e s i n v o l v e d i n p e r m a f r o s t . H o p e f u l l y in t h e n e a r f u t u r e w e w i l l b e

a b l e t o f o r m u l a t e s o m e p r o p o s a l w h i c h m e e t s w i t h y o u r a p p r o v a l t o p r o c e e d w i t h t h e f o r m a t i o n o f a n i n t e r n a t i o n a l a s s o c - i a t i o n . I f a n y o f y o u w i s h t o w r i t e t o m e a t a l a t e r d a t e t o a s k how t h e s e mat- t e r s a r e p r o c e e d i n g , 1 w i l l b e p l e a s e d t o i n f o r m y o u o f o u r p r o g r e s s . We w i l l c i r - c u l a t e w r i t t e n c o m m u n i c a t i o n s a b o u t o u r d e l i b e r a t i o n s .

T h e n e x t i t e m o n t h i s a f t e r n o o n ' s p r o g r a m i s t h a t P r o f e s s o r M e l i n k o v , t h e h e a d o f t h e S o v i e t D e l e g a t i o n , w i s h e s t o make a f e w r e m a r k s .

P r o f e s s o r P . 1 . M e l i n k o v : Mr. C h a i r m a n , L a d i e s a n d G e n t l e m e n , I a n d t h e e n t i r e S o v i e t d e l e g a t i o n h a v e b e e n v e r y p l e a s e d t o p a r t i c i p a t e i n t h i s C o n f e r e n c e . I t o o k p a r t i n t h e w o r k o f t h e F i r s t I n t e r n a t i o n a l C o n f e r e n c e On P e r m a f r o s t . I w a s t h e c h i e f o r g a n i z e r o f t h e S e c o n d C o n f e r e n c e a n d now w e a r e h e r e a t t h e T h i r d C o n f e r e n c e . I a m g l a d t o s e e t h a t t h e n u m b e r o f p a r t i c i p a n t s i s c o n t i n u - o u s l y g r o w i n g , a n d I h o p e t h a t t h e r e w i l l b e t w i c e a s m a n y p e o p l e a t t h e F o u r t h I n t e r n a t i o n a l C o n f e r e n c e . I n t h e S o v i e t U n i o n w e h a v e m o r e t h a n 1 , 0 0 0 s c i e n t i s t s a n d t e c h n i c i a n s w o r k i n g i n t h e f i e l d o f p e r m a f r o s t s c i e n c e . Two d e p a r t m e n t s a t Moscow S t a t e U n i v e r s i t y a r e t r a i n i n g e x p e r t s i n p e r m a f r o s t . A n e w d e p a r t m e n t i s b e i n g e s t a b l i s h e d a t t h e U n i v e r s i t y o f Y a k u t s k a n d w i l l b e g i n f u n c t i o n i n g l a t e r t h i s y e a r . A s f o r p e r m a f r o s t e n g i n e e r i n g , q u i t e a f e w d e p a r t m e n t s a c r o s s t h e c o u n t r y a r e g i v i n g l e c t u r e s a n d c o u r s e s o n t h e s u b j e c t . A s y o u k n o w , o u r p e r m a f r o s t r e g i o n o c c u p i e s r o u g h l y 50% o f t h e t o t a l d r y l a n d o f r h e S o v i e t U n i o n . M o r e a n d m o r e e f f o r t i s b e i n g p u t i n t o t h e d e v e l o p m e n t o f o u r n o r t h e r n r e g i o n s , a n d t h e n e e d f o r p e r m a f r o s t e x p e r t s i s c o n t i n u o u s l y g r o w i n g , 1 d o n o t k n o w h o w p e r m a f r o s t s c i e n t i s t s a r e b e i n g t r a i n e d i n C a n a d a a n d t h e U n i t e d S t a t e s , b u t I f e e l t h a t t h i s a s p e c t i s e x t r e m e l y i m p o r t a n t . I f e e l t h a t t h e c r e a t i o n o f a new i n t e r - n a t i o n a l a s s o c i a t i o n i s r e l e v a n t t o t h i s a n d i t i s h o p e d t h a t i t w i l l b e a b l e to h a v e s o m e i n f l u e n c e i n d e v e l o p i n g new m e t h o d s f o r t r a i n i n g p e r m a f r o s t s c i e n t i s t s

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We f u l l y s u p p o r t t h e i d e a o f t h i s new a s s o c i a t i o n . A t t h e S e c o n d C o n f e r e n c e I d i d h a v e s o m e d i s c u s s i o n s w i t h Dr. Brown a n d Dr. PGw6 a b o u t t h e p o s s i b i l i t y o f p u b l i s h i n g a n i n t e r n a t i o n a l j o u r n a l o n p e r m a f r o s t . Somehow t h i s was n e v e r m e n t i o n e d a g a i n a n d i t a p p e a r s t h a t n o t h i n g h a s b e e n d o n e . I t h i n k t h a t w h e n we b e g i n d i s c u s s i o n s a b o u t o r g a n i z i n g t h i s new a s s o c i a r i o n , w e s h o u l d a l s o m e n t i o n t h i s p o s s i b i l i t y o f p u b l i s h i n g a new j o u r n a l o n p e r m a f r o s t ,

Now I w o u l d l i k e t o l e a v e a s o u v e n i r w i t h t h e C h a i r m a n o f t h e O r g a n i z i n g C o m m i t t e e f o r t h e T h i r d I n t e r n a t i o n a l C o n f e r e n c e , my v e r y g o o d a n d o l d f r i e n d , D r . Roge r Brown . I t i s a v e r y a n c i e n t Y a k u t v e s s e l c a l l e d a " s h a r o m " . We h a v e a n a t i o n a l h o l i d a y i n t h e Y a k u t R e p u b l i c a n d o n t h i s d a y t h e p e o p l e d r i n k k u m i s s ( m a r e ' s m i l k ) f r o m t h i s v e s s e l . We t r i e d t o f i n d t h e m o s t a n c i e n t v e s s e l a v a i l a b l e i n t h e Y a k u t R e p u b l i c . T h e r e a r e v a r i o u s d e s i g n s o n t h i s p a r t i c u l a r v e s s e l a n d a s p e c i a l o n e . w h i c h i n d i c a t e s t h a t i t was made e n t i r e l y by h a n d a t l e a s t 1 5 0 y e a r s a g o . T h e r e i s s o m e i n f o r m a t i o n c o n c e r n - i n g t h e f a c t t h a t w h e n t h e f a m o u s S h e r g i n s h a f t was b e i n g s u n k i n Y a k u t s k , t h e r e n o w n e d R u s s i a n g e o g r a p h e r a n d s c i e n t i s t M i d d e n d o r f was p a s s i n g t h r o u g h t h e a r e a a n d i t i s q u i t e p o s s i b l e t h a t h e d r a n k f r o m t h i s v e s s e l . I t i s o f c o u r s e a museum p i e c e o f t h e g r e a t e s t h i s t o r i c a l v a l u e a n d i n o r d e r t o b r f n g t h i s v e s s e l t o C a n a d a w e h a d t o o b t a i n s p e c i a l p e r - m i s s i o n f r o m o u r M i n i s t r y o f C u l t u r e . I t i s w i t h g r e a t p l e a s u r e t h a t I am l e a v i n g t h i s s o u v e n i r h e r e w i t h c o l l e a g u e s who w o r k i n this n e w a n d w o n d e r f u l f i e l d o f p e r m a f r o s t s c f e n c e .

Dr. R . J . E . B r o w n : P r o f e s s o r M e l i n k o v , t h a n k y o u v e r y m u c h f o r t h i s v e r y b e a u t i - f u l g i f t w h i c h y o u h a v e g i v e n t o u s . I t i s a g r e a t p r i v i l e g e for me t o b e t h e t r u s t e e o f t h i s v e r y b e a u t i f u l v e s s e l . I w i l l r a k e i t t o Ottawa a n d p u t it o n d i s p l a y a t t h e N a t i o n a l R e s e a r c h C o u n c i l o f C a n a d a . P e o p l e w i l l b e a b l e t o s e e i t , a n d l e a r n o f t h e g e n e r o s i t y o f y o u a n d y o u r S o v i e t c o l l e a g u e s . I h o p e t h a t some day i n t h e n o t t o o d i s t a n t f u t u r e , p e r h a p s ' a t t h e f i r s t m e e t i n g o f t h e new i n t e r n a t i o n a l p e r m a f r o s t a s s o c i a t i o n , w e m i g h t i n t h e Y a k u t i a n t r a d i t i o n , f i l l t h e v e s s e l w i t h k u m i s s a n d p a s s i t a r o u n d s o t h a t a l l may d r i n k f r o m i t . L s h o u l d l i k e p e o p l e h e r e t o h a v e t h e o p p o r t u n i t y o f e x a m i n i n g t h i s b e a u t i f u l o b j e c t s o I w i l l l e a v e i t o n t h e t a b l e . Again o u r s i n c e r e t h a n k s $0 P r o f e s s o r M e l n i k o v .

Now I w o u l d l i k e t o c a l l an D r . P e w i , t h e l e a d e r o f t h e d e l e g a t i o n f r o m t h e U n i t e d S t a t e s f o r s o m e r e m a r k s ,

D r . T ,L . Pgwg: Thank you , Mr. C h a i r m a n . I t w a s i n 1 9 6 2 t h a t a small g r o u p o f s c i e n t i s t s a n d e n g i n e e r s , s p u r r e d o n by D r . K . B . Woods, on b e h a l f o f t h e N a t i o n a l A c a d e m y o f S c i e n c e s o f t h e U n i t e d S t a t e s o r g a n i z e d a m e e t i n g t h a t was h e l d i n 1 9 6 3 . We know now o f t h i s m e e t i n g a s t h e F i r s t I n t e r n a t i o n a l C o n f e r e n c e On P e r m a f r o s t . I t w a s t h e r e s u l t in l a r g e p a r t o f t h e e x p a n s i o n o f i n t e r e s t i n p e r m a f r o s t d u r i n g t h e S e c o n d W o r l d War and immedi - a t e l y a f t e r w a r d s , The S o v i e t U n i o n w h i c h h a s a l o n g r e c o r d o f s y s t e m a t i c s t u d i e s i n p e r m a f r o s t , i n l a r g e p a r t a s s o c i a t e d w i t h t h e i r n a t i o n a l Academy o f S c i e n c e s , moved t h i s a c t i v i t y r a p i d l y t h r o u g h t h e s t a g e o f w h a t m i g h t h a v e b e e n c a l l e d a g r o u p , t o a c o m m i t t e e , t h e n a c o m m i s s i o n , a n d f i n a l l y a n i n s t i t u t e . I t i s t h i s P e r m a f r o s t I n s t i t u t e u n d e r t h e d i r e c t i o n o f P r o f e s s o r M e l i r i k o v w h i c h p l a n n e d t h e h i s t o r i c S e c o n d I n t e r n a t i o n a l C o n f e r e n c e On P e r m a f r o s t a t Y a k u t s k i n 1 9 7 3 . Con- t i n u e d a n d r a p i d e x p a n s i o n o f p e r m a f r o s t i n v e s t i g a t i o n s a n d t h e u t i l i z a t i o n o f n o r t h e r n r e s o u r c e s e n s u e d . Now o n l y f i v e y e a r s l a t e r t o d a y p e r m a f r o s t h a s come of a g e w i t h t h e T h i r d I n t e r n a t i o n a l C o n f e r - e n c e On P e r m a f r o s t h o s t e d b y C a n a d a . On b e h a l f o f t h e U n i t e d S t a t e s d e l e g a t i o n a n d a l l p a r t i c i p a n t s f r o m my c o u n t r y , I w a n t t o t h a n k y o u , Mr. C h a i r m a n , a n d y o u r i n d u s t r i o u s s r a f f , f o r t h e w o n d e r f u l Con- f e r e n c e t h a t y o u a n d y o u r g r o u p h a v e o r g a n i z e d . We h a v e a l l p r o f i t t e d g r e a t l y Erom t h e o p p o r t u n i t y t o e x c h a n g e i n f o r m - ation with w o r k e r s f r o m a l l p a r t s o f t h e w o r l d . Now w i t h t h e i m p o r t a n c e o f p e r m a - f r o s t a n d t h e n u m b e r o f p e r m a f r o s t i n v e s t i g a t i o n s i n c r e a s i n g e v e r y d a y , i t i s a p p r o p r i a t e t h a t t h i s i n t e r n a t i o n a l e x c h a n g e b e c o n t i n u e d .

I t g i v e s m e g r e a t p l e a s u r e t o s u b m i t a n i n v i t a t i o n t o h o s t t h e F o u r t h Z n t e r - n a t i o n a l C o n f e r e n c e On P e r m a f r o s t o n b e h a l f o f t h e N a t i o n a l A c a d e m y o f S c i e n c e s o f t h e U n i t e d S t a t e s t h r o u g h t h e P o l a r R e s e a r c h B o a r d o f t h e A c a d e m y . I h a v e b e e n a u t h o r i z e d t o e x t e n d t h i s i n v i t a t i o n f o r t h e F o u r t h C o n f e r e n c e i n t h e U n i t e d S t a r e s p e r h a p s i n f o u r o r f i v e y e a r s . F u r t h e r m o r e , X a m h a p p y t o r e p o r t t h a t t h i s g e n e r o u s i n v i t a t i o n h a s come f rom t h e c e n t r e o f t h e p e r m a f r o s t a r e a o f t h e U n i t e d S t a t e s a n d f r o m my f o r m e r i n s t i t u t i o n . One o f t h e c e n t r e s o f p e r m a f r o s t r e s e a r c h i n t h e U n i t e d S t a t e s i s i n F a i r b a n k s , Alaska. F r o m t h e d a y s o f t h e p l a c e r g o l d m i n i n g i n 1 9 0 2 u n t i l t c d a y , c e n t r a l A l a s k a h a s b e e n a n a r ea of v a r i o u s p e r m a f r o s t i n v e s t i g a t i o n s . T h r o u g h t h e c o u r t e s y o f D r . Howard C u t l e r , C h a n c e l l o r o f t h e U n i v e r s i t y o f A l a s k a a t F a i r b a n k s , I am a u t h o r i z e d t o e x t e n d a n i n v i t a t t o n f r o m t h a t u n i v e r - s i t y t o h o s t t h e F o u r t h I n t e r n a t i o n a l C o n f e r e n c e On P e r m a f r o s t on i t s c a m p u s .

T h e U n i t e d S t a r e s w e l c o m e s a l l o f y o u a n d a l l p e r m a f r o s t w o r k e r s t h r o u g h o u t w o r l d t o t h i s f o r t h c o m i n g C o n f e r e n c e . T h a n k y o u v e r y m u c h .

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D r . R,J.E. Brown: Thank you ve ry much , D r . P E w E . On b e h a l f o f t h e O r g a n i z i n g C o m m i t t e e f o r t h e T h i r d I n t e r n a t i o n a l C o n f e r e n c e On P e r m a f r o s t a n d t h e p a r t i c i - p a n t s a t t h i s C o n f e r e n c e , I am v e r y p l e a s e d t o a c c e p t y o u r i n v i t a t i o n a n d we l o o k f o r w a r d t o r e c e i v i n g news o f d e v e l o p - i n g a r r a n g e m e n t s f o r t h e n e x t C o n f e r e n c e , I t i s v e r y f i t t i n g i n d e e d t h a t we h a v e r e c e i v e d t h i s o p p o r t u n i t y t o v i s i t A l a s k a a f e w y e a r s f r o m n o w , t o s e e t h e p e r m a - f r o s t r e g i o n w h i c h l i e s b e t w e e n n o r t h e r n C a n a d a a n d S i b e r i a . I n t h e c o u r s e o f a b o u t t e n y e a r s , w e w i l l h a v e met i n v i r t u a l l y a l l o f t h e p e r m a f r o s t r e g i o n s i n t h e n o r t h e r n h e m i s p h e r e . A g a i n w e t h a n k y o u v e r y m u c h , Dr. PEwE.

To c o n t i n u e t h i s t h o u g h t f o r a m o m e n t , d u r i n g t h e m e e t i n g s h e r e , I a m c e r t a i n t h a t y o u h a v e a l l n o t i c e d a l a r g e b a n n e r h a n g i n g on t h e w a l l a t o n e e n d o f t h i s r o o m . T h e n a m e o f o u r i n t e r n a t i o n a l p e r m a f r o s t c o n f e r e n c e i s o n i t i n t h e t h r e e o f f i c i a l l a n g u a g e s , T h e l o g o s o r e m b l e m s o f t h e S e c o n d a n d T h i r d I n t e r - n a t i o n a l C o n f e r e n c e s On P e r m a f r o s t a r e i n t h e l o w e r l e f t - h a n d c o r n e r a n d a s p a c e f o r t h e o n e o f t h e F i r s t C o n f e r e n c e , i f o n e e x i s t s . I s h o u l d l i k e t o p r e s e n t t h i s b a n n e r now t o D r . PEw6 a n d I c h a r g e h i m w i t h t h e r e s p o n s i b i l i t y o f L o o k i n g a f t e r it u n t i l t h e n e x t C o n f e r e n c e . O u r A m e r i c a n c o l l e a g u e s can p l a c e t h e e m b l e m f o r t h e F o u r t h C o n f e r e n c e on t h e b a n n e r a n d f o r t h e F i r s t , i f t h e y w i s h t o i n v e n t o n e .

Dr. T . L . P B w & : Thank you M r . C h a i r m a n a n d t h e w o r k e r s , a n d t h e a r t i s t who c r e a t e d t h i s w o n d e r f u l p i e c e o f w o r k . I h o p e t h a t I c a n k e e p t r a c k o f i t o v e r t h e n e x t f e w y e a r s a n d w h e n t h e t ime c o m e s , i t w i l l b e p r o m i n e n t l y d i s p l a y e d w i t h two a d d i t i o n a l l o g o s .

D r . R . J . E . Brown: We h a v e now r e a c h e d t h e e n d o f t h e f o r m a l p r o g r a m f o r t h i s T h i r d I n t e r n a t i o n a l C o n f e r e n c e On P e r m a - f r o s t . Soon w e w i l l b e g o i n g o u r s e p a r a t e ways , 3ome o f u s o n t h e f i e l d t r i p s , w h i c h l e a v e E d m o n t o n t o m o r r o w m o r n i n g , A g a i n I: w o u l d l i k e t o s a y t h a n k y o u v e r y much f o r c o m i n g , and u n t i l we m e e t a g a i n , b e s t w i s h e s t o e v e r y o n e . I d e c l a r e t h e T h i r d I n t e r n a t i o n a l C o n f e r e n c e On P e r m a - f r o s t t o b e o f f i c i a l l y c l o s e d . T h a n k y o u v e r y m u c h ,

240

"""""""- POSTEA SESSIONSIS~ANCES DE PLANCHES E X P L I C ATIVE~

1,

2 .

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4 .

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11.

C A R D , J . , S u n O i l C o m p a n y L i m i t e d , C a l g a r y , A l b e r t a , C a p a d a .

R E C O G N I T I O N OF P E R M A F R O S T E F F E C T S I N R E F L E C T I O N S E I S M I C D A T A ,

C R A M P T O N , C . B . , D e p a r t m e n t o f G e o g r a p h y , S i m o n F ra se r U n i v e r s i t y , B u r n a b y , B . C . C a n a d a .

S Y N E R G I S M A N D M U L T I P L E - R E S O L U T I O N A N A L Y S I S F O R T E R R A I N E V A L U A T I O N .

E V E R E T T , K . R . , I n s t i t u t e of P o l a r S t u d i e s , C o l u m b u s , O h i o , W . S . A .

W E B B E R , P . J . a n d W A L K E R , D . A . , I n s t i t u t e o f A r c t i c a n d A l p i n e R e s e a r c h , B o u l d e r , C o l o r a d o , U . S . A .

BROWN, J . , U . S . A r m y C o l d R e g i o n s R e s e a r c h a n d E n g i n e e r i n g L a b o r a t o r y , H a n o v e r , N . H . , W.S.A,

G E O E C O L O E I C A L M A P P I N G I N A L A S K A N C O A S T A L T A N D R A .

G I L L , D . a n d K E R S H A W , G . P . , D e p a r t m e n t o f G e o g r a p h y , U n i v e r s i t y o f A l b e r t a , E d m o n t o n , A l b e r t a , C a n a d a .

P A L S A - P E A T P L A T E A U S T U D I E S "IN T H E M A C M I L L A N P A S S - T S I C H U R I V E R A R E A , N O R T H W E S T T E R R I T O R I E S , C A N A D A .

G I M B A R Z E V S K Y , P . , C a n a d i a n F o r e s t r y S e r v i c e , E n v i r o n m e n t C a n a d a , O t t a w a , O n c a r i o , C a n a d a .

A I R P H O T O A N A L Y S I S OF P E R M A F R O S T L A N D S C A P E S .

J E S S B U R G E R , H . L . , D e p a r t m e n t o f C i v i l E n g i n e e r i n g , R u h r U n i v e r s i t y , B o c h u m , F e d e r a l R e p u b l i c o f G e r m a n y .

T H E F I R S T I N T E R N A T I O N A L S Y M P O S I U M O N G R O U N D F R E E Z I N G .

K A Y , B . D . , G R O E N E V E L T , P . H . a n d J A C K M A N , J . A . , D e p a r t m e n t o f L a n d R e s o u r c e S c i e n c e , U n i v e r s i t y o f G u e l p h , G u e l p h , O n t a r i o , C a n a d a .

T H E U T I L l T Y OF GAMMA R A D I A T I O N I N M E A S U R I N G W A T E R A N D S O L U T E T R A N S P O R T I N S O I L S F R E E Z I N G U N l l E R L A B O R A T O R Y C O N D I T I O N S .

K L O H N , E . J . , K l o h n L e o n o f f C o n s u l t a n t s L i m i t e d , V a n c o u v e r , B . C . , C a n a d a .

C O N S T R U C T I O N I N P E R M A F R O S T T E R R A I N .

K L O H N , E . J . , U A V I S O N , D . M . , a n d E D G E W O R T H , A . L . , K l o h n L e o n o f f C o n s u l t a n t s L i m i t e d , V a n c o u v e r , B.C., Canada, and C a l g a r y , A l b e r t a , C a n a d a .

I N S U L A T E D F O U N D A T I O N S .

O L H O E F T , G , R . , U . S . G e o l o g i c a l S u r v e y , D e n v e r , C o l o r a d o , U . S . A .

E F F E C T S O F MAN MADE S T R U C T U R E S ON P E R M A F R O S T A S S E E N BY R A D A R .

P I L O N , J.A. a n d P I C H E T T E , D . R . , D e f e n c e R e s e a r c h E s t a b l i s h m e n t , D e p a r t m e n t o f N a t i o n a l D e f e n c e , O t t a w a , O n t a r i o , C a n a d a .

T H E D . R . E . O . S O I L T E M P E R A T U R E P R O B E .

241

1 2 . R E I D , R . L . , D e p a r t m e n t o f M e c h a n i c a l E n g i n e e r i n g , U n i v e r s i t y o f T e n n e s s e e , K n o x v i l l e , T e n n e s s e e , U . S . A .

G O L D S T E I N , M . E . , N A S A L e w i s R e s e a r c h C e n t e r , C l e v e l a n d , O h i o , U . S . A .

F R E E Z I N G A N D T H A W I N G O F P E R M A F R O S T I N T H E P R E S E N C E O F G R O U N D W A T E R FLOW.

13. V A N E V E R D I N G E N , R . O . , H y d r o l o g y R e s e a r c h D i v i s i o n , E n v i r o n m e n t C a n a d a , C a l g a r y , A l b e r K a , C a n a d a .

FROST B L I S T E R S ( H Y D R O L A C C O L I T H S ) A T B E A R R O C K , N . W . T .

1 4 . VAN E V E R D I N G E N , R . O . , H y d r o l o g y R e s e a r c h D i v i s i o n , E n v i r o n m e n t C a n a d a , C a l g a r y , A l b e r t a , C a n a d a .

K A R S T I N P E R M A F R O S T T E R R A I N N E A R G R E A T B E A R L A K E .

1 5 . W I L S O N , M . D . , D e p a r t m e n t o f G e o l o g y a n d G e o p h y s i c s , B o i s e S t a t e U n i v e r s i t y , B o i s e , I d a h o , U . S . A .

P A T T E R N E D G R O U N D OF E R O S I O N A L O R I G I N , S O U T H W E S T E R N I D A H O .

242

T i t l e :

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1. THE JAMES BAY DEVELOPMENT ( 2 0 m i n u t e s )

F i e l d i n v e s t i g a t i o n s i n c o n n e c t i o n w i t h t h e J a m e s B a y H y d r o e l e c t r i c P r o j e c t i n N o r t h e r n Q u e b e c .

Mrs. D e x t r a z e , S o c i Q t E d e D d v e l o p p e m e n t d e l a B a i e J a m e s , 800 e s t , d e M a i s o n n e u v e , M o n t r G a l , Q u e b e c , C a n a d a .

2 . SUB ZERO POWER ( 2 0 m i n u t e s )

Mrs. D e x t r a z e , S o c i E t E d e R E v e l o p p e m e n t d e l a B a i e James, 800 e s t , d e M a i s o n n e u v e , M o n t r g a l , Q u B b e c , C a n a d a .

3 . E R G E OF E V O L U T I O N ( 4 0 m i n u t e s )

N o r t h e r n e c o l o g y , e s p e c i a l l y i n c o n n e c t i o n w i t h m u s k e g .

I m p e r i a l O i l L i m i t e d ( D i s t r i b u t e d b y C i t y F i l m s ) , E s s o B u i l d i n g , 2 P l a c e V i l l e M a r i e , M o n t r e a l , Q u e b e c , C a n a d a .

4 . THE MISSING L I N K ( 2 0 m i n u t e s )

C o n s t r u c t i o n o f a l a n d i n g s t r i p i n t h e A r c t i c .

Dr. G . J a c o b s e n , The Tower C o m p a n y L i m i t e d , S u i t e 1 5 , 1 3 9 0 S h e r b r o o k e S t r e e t West, M o n t r E a l , Q u E b e c , C a n a d a .

5 . N O R T H TO T U K ( 2 0 m i n u t e s )

Mrs. Anne Burne t t , F e d e r a l C o m m e r c e a n d N a v i g a t i o n L i m i t e d , S t o c k E x c h a n g e T o w e r , 800 V i c t o r i a S q u a r e , M o n t r E a l , Q u E b e c , C a n a d a , H 4 Z 1C4.

243

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6 . T R I A L BY I C E ( 4 0 m i n u t e s )

1 , n v e s t i g a t i o n s f o r g a s p i p e l i n e c o n s t r u c t i o n i n t h e A r c t i c .

Ms. B . U n d e r h i l l , P u b l i c a t i o n E d i t o r , P o l a r Gas P r o j e c t , P , O . Box 9 0 , C o m m e r c e C o u r t West, T o r o n t o , O n t a r i o ; C a n a d a , M5L 1H3.

7 . I C E A C T I O N O N B R I D G E P IERS ( 3 0 m i n u t e s )

Mr. S . B e l t a o s , R e s e a r c h O f f i c e r , A l b e r t a R e s e a r c h C o u n c i l , 3 0 3 C i v i l - E l e c t r i c a l B u i l d i n g , U n i v e r s i t y o f A l b e r t a , E d m o n t o n , A l b e r t a , C a n a d a , T6G 2 G 7 .

8 . T H E P E R M A F R O S T F R O N T I E R ( 2 5 m i n u t e s ) 9 . P I P E L I N E ( 2 0 m i n u t e s )

Mr. J o h n R a t t e r m a n , P u b l i c R e l a t i o n s D e p a r t m e n t , A l y e s k a P i p e l i n e S e r v i c e Company, 1 8 2 5 S o u t h B r a g a w S t r e e t , A n c h o r a g e , A l a s k a , U . S . A . 9 9 5 0 4 .

T i t l e s : 1 0 . THE MANHATTEN O D Y S S E Y ( 1 0 m i n u t e s ) 11. HOW TO B U I L D A N I G L O O (LO m i n u t e s ) 1 2 . NORTHWEST PASSAGE ( 2 7 m i n u t e s ) 1 3 . SEARCH I N T O W H I T E SPACE ( 1 7 m i n u t e s )

A d d r e s s : Mrs. J u l i e t t e B a s t i e n , F i l m L i b r a r i a n , N a t i o n a l F i l m B o a r d , 1 0 0 3 1 - 1 0 3 Avenue, E d m o n t o n , A l b e r t a , C a n a d a , T 5 J OL9

244

EXHIBITORS/EXPOSANTS

1. ARCTIC FOUNDATIONS INCORPORATED

P r o d u c t s on E x h i b i t : T h e r m o - r i n g p i l e s , r i g i d a n d f l e x i b l e t h e r m o - p r o b e s +

M a i l i n g A d d r e s s : A r c t i c F o u n d a t i o n s I n c . , 6 6 1 3 A r c t i c B l v d . , A n c h o r a g e , A l a s k a , 9 9 5 0 2 U . S , A .

2 . C R O W L E Y ALL T E R R A I N CORPORATION

P r o d u c t s on E x h i b i t :

M a i l i n g A d d r e s s :

CATCO RD-85 w i t h RDT-45 t r a i l e r u n i t . D e s i g n e d t o c a r r y l a r g e p a y l o a d s i n t h e A r c t i c o v e r un- p r e p a r e d s u r f a c e s w i t h m i n i m u m d a m a g e t o s u r f a c e a n d v e g e t a t i o n

C r o w l e y A l l T e r r a i n G o r p . , F o u r t h & B a t t e r y B l d g . , 2 4 0 1 F o u r t h A v e . , S e a t t l e , W a s h i n g t o n , 9 8 1 2 1 U .S .A .

3 . DOW C H E M

P r o d u c t s

A L I I C A L OF C A N A D

on E x h i b i t :


M I T E D

S t y r o f o a m H 1 b r a n d e x t r u d e d , e x p a n d e d p o l y s t y r e n e f o a m i n s u l a t i o n .

Dow C h e m i c a l o f C a n a d a L i m i t e d , P . O . Box 1 0 1 2 , S a r n i a , O n t a r i o , C a n a d a , N 7 T 7 K 7 .

4 . E B A E N G I N E E R I N G CONSULTANTS L I M I T E D

P r o d u c t s on E x h i b i t : T n r e c e n t y e a r s E B A E n g i n e e r i n g C o n s u l t a n t s L i m i t e d h a v e b e e n i n v o l v e d i n n u m e r o u s , unique p r o j e c t s t h r o u g h o u t t h e C a n a d i a n n o r t h . A g e n e r a l s l i d e p r e s e n t a t i o n a n d p h o t o g r a p h i c d i s p l a y o f some o f t h e s e s i t e s , p r o j e c t s a n d f i e l d a c t i v i t i e s w i l l b e shown i n c l u d i n g s p e c i a l i z e d l a b o r a t o r y a n d s a m p l i n g e q u i p m e n t .

M a i l i n g A d d r e s s : EBA E n g i n e e r i n g C o n s u l t a n t s L t d . , 1 4 5 3 5 - 1 1 8 A v e n u e , E d m o n r o n , A l b e r t a , C a n a d a .

245

5 . F I B E R L I T E PRODUCTS COMPANY L I M I T E D

P r o d u c t s o n E x h i b i t : S e c t i o n s o f U-Dor, s e l f c o n t a i n e d a n d s e l f s u p p o r t i n g i n s u l a t e d s e r v i c e s f o r s e w a g e a n d w a t e r l i n e s , a n d d e m o n s t r a t i o n s o f s e r v i c e c o n n e c t i o n s f o r U t i l i d e t s a n d h y d r a n t s ,

M a i l i n g A d d r e s s : F i b e r l i r e P r o d u c t s C o . L t d . , 4 9 2 0 - 7 6 A v e n u e , E d m o n t o n , A l b e r t a , C a n a d a a

6 . G E O L O G I C A L S U R V E Y OF C A N A D A

P r o d u c t s o n E x h i b i t : L i g h t w e i g h t s o i l d r i l l i n g a n d s a m p l i n g e q u i p m e n t d e s i g n e d f o r f r o z e n g r o u n d a n d r e m o t e a r e a s . D e s i g n e d b y T e r r a i n S c i e n c e s D i v i s i o n a n d T e c h n i c a l F i e l d S u p p o r t S e r v i c e s , D e p a r t m e n t o f E n e r g y M i n e s and R e s o u r c e s .


7 . G E O N I C S L I M I T E D

P r o d u c t s o n E x h i b i t :


G e o l o g i c a l S u r v e y o f C a n a d a , D e p t . o f E n e r g y , M i n e s & R e s o u r c e s , 6 0 1 B o o t h S t r e e t , O t t a w a , O n t a r i o , C a n a d a K1A O E 8 .

E l e c t r o m a g n e t i c i n s t r u m e n t a t i o n f o r t h e r e m o t e m e a s u r e m e n t o f t e r r a i n e l e c t r i c a l c o n d u c t i v i t y f r o m t h e s u r f a c e o r i n t h e a i r .

G e o n i c s L i m i t e d , 1 7 4 5 M e y e r s i d e D r i v e , M i s s i s s a u g a , O n t a r i o , C a n a d a L 5 T 1 C 5 .

8 . R.M. H A R D Y A N D A S S O C T A T E S L I M I T E D

P r o d u c t s o n E x h i b i t : R . M . H a r d y a n d A s s o c i a t e s L t d , w i l l d e m o n s t r a t e i t s e x p e r i e n c e in s i n g u l a r a n d m u l t i - d i s c i p l i n e d t e c h n o l o g i e s o f g e o t e c h n i c a l , m a t e r i a l s a n d m e t a l l u r g i c a l e n g i - n e e r i n g , e n v i r o n m e n t a l a n d c h e m i c a l s c i e n c e s r e l a t e d t o c o n s t r u c t i o n a n d r e s o u r c e d e v e l o p - m e n t I n a r c t i c a n d s u b a r c t i c r e g i o n s a n d d i s p l a y a p p l i c a t i o n s o f a n a l y s i s d e s i g n a n d € i e l d a n d l a b o r a t o r y t e s t i n g c a p a b i l i t i e s .

M a i l i n g A d d r e s s : R . M . H a r d y & A s s o c i a t e s L t d . , P.O. Box 7 4 6 , 4 8 1 0 - 9 3 S t r e e t , E d m o n t o n , A l b e r t a , C a n a d a , T 5 J 2L4.

246

9 . S L O P E I N D I C A T O R COMPANY

P r o d u c t s o n E x h i b i t :


I n s t r u m e n t s f o r t h e g e o t e c h n i c a l , g e o p h y s i c . a l , s t r u c t u r a l , m i n i n g , h y d r o l o g i c a l a n d r o c k m e c h a n i c s f i e l d s

S l o p e I n d i c a t o r C o m p a n y , 3 6 6 8 A l b i o n P l a c e N o r t h , S e a t t l e , W a s h i n g t o n , 9 8 1 0 3 U .S .A .

1 0 . U.S. ARMY C O L D REGTONS RESEARCH A N D E N G I N E E R I N G LABORATORY

P r o d u c t s o n E x h i b i t : T h e U . S , Army C o l d R e g i o n s R e s e a r c h a n d E n g i n e e r i n g L a b o r a t o r y s e e k s t o d i s c o v e r a n d u n d e r s t a n d t h e n a t u r a l p h e n o m e n a o f c o l d r e g i o n s , e s p e c i a l l y w i n t e r c o n d i t i o n s , a n d t o d e v i s e a n d r e f i n e m e t h o d s f o r b u i l d i n g , t r a v e l l i n g , l i v i n g a n d w o r k i n g t h e r e . S t u d i e s p e r t a i n to c h a r a c t e r i s t i c s a n d e v e n t s u n i q u e to c o l d e n v i r o n m e n t s , a n d t o d e s i g n o f f a c i l i t i e s , s t r u c t u r e s , and e q u i p m e n t , u s e d i n t hese e n v i r o n m e n t s .

M a i l i n g A d d r e s s : U . S . Army C o l d R e g i o n s Research a n d E n g i n e e r i n g L a b o r a t o r y ,

Box 2 8 2 , Lyrne R o a d , H a n o v e r , N e w H a m p s h i r e , 0 3 7 5 5 U . S . A .

11. WESTBAY INSTRUMENTS LIMITED

P r o d u c t s o n e x h i b i t : G r o u n d w a t e r i n s t r u m e n t a t i o n : m u l t i p l e p i e z o m e t e r s , m u l t i p l e z o n e s a m p l i n g s y s t e m s . G e o - t e c h n i c a l i n s t r u m e n t a t i o n : c o m b i n e d p i e z o m e t e r i n c l i n o m e t e r s y s t e m . P i e z o m e t r i c p e r m e a b i l i t y p r o f i l e s .

M a i l i n g A d d r e s s : Westbay I n s t r u m e n t s L t d . S u i t e lB, 2 6 5 - 2 5 t h S t r e e t , W e s t V a n c o u v e r , B . C . , C a n a d a , V7V 4 H 9 .

24 7

.L. Aamodt,

O.0. Box 1663 MS 586, os Alamos Scientific Lab.

>OS ALamO6, N.M. 87545

F.L. Abbey, Div. of Hydrology, univ. of Saskatchewan, Saskatoon, Sask. S7N OW0

R.D. Abbott, Shannon & Wilson Inc., P.O. Box 843, Fairbanks, AK. 99707

H. Acheson Panarctic Oils Ltd. Box 190, Calgary, Alta. T2P 2H6

J. Aguirre PUFnte, Laboratoire d'herothermique

4 Tef, ROUte des GatdeS, 92190 Meudon, France

O.B. Andersland,

Michigan State University, Dept. of Civil Engineering,

East Lansing, MI 48824

D.M. Anderson, National Science Foundation, 11670 Mediterranean Ct. Reston, VA 22090

J.C. Anderson, Glaciology Div. Environment Canada, Ottawa, Ont. KIA OE7

K.O. Anderson, University of Alberta, Dept. oL Civil Engineering, Edmonton, Alta. T6G 2H4

L.W. Anderson, Fugro Inc. 3777 Long Beach Blvd. P.O. Box 7765,

dU C.N.R.S.,

Long Beach, CA 90807

R. S . Anderson, StanEord University, Geology Dept., Stanford, CA 94305

A.P. Annan, Geological Survey of Canada, 601 Booth St. Ottawa, Ont. KIA OE8

E.P. Antoniades. Chevron Research Co. P.O. Box 1627, Richmond, CA 94802

S . Arcone, USA CRREL P . O . Box 282, Hanover, N.H. 03755

V. Arkhanguelski, USSR, Leningrad,

LESY, Cafedza Foundation, 2a Krashoazmeyskay 4,

U.S.S.R.

C. Arnold, Bechtel Inc. P.O. Box 3965, $an Francisco, CA 94119

J. Artcau, Dept. de ginie civil, Local A-37

C.P. 6079, Succ. "A", Ecole Polytechnique,

Montreal, P.Q. W3C 3A7

W.D. Arvidson, GeOCOn (1975) Ltd.

Calgary, Alta. T2P 187 301 - 805 - Eth Ave. S.W.

G. Black, Geonics Ltd.

MiSaiSEaUga, Ont. L5T 1C5 1745 Meyerside Dr.

B.L. Baggott, R.F. Black, Shawini an Engineering western Ltd., 808 - 4jh Ave. S.W.,

Dept. of Geology & Geophysics U-45 University of Connecticut

Calgary, Alta. T2P OR4 Storrs, CT 06268

R.J. Baird, fnst, of Sedimentary L Petroleum Geology Geoloqical Survey of Canada, Edmonton, Alta. T5G 2x3

L.W. Blackman, W.L. Wardtop h Associates Ltd. 11230 - 119 S t .

Energy, Mines ti Resources, 3303 - 33rd St. N.W. Lac. Bliss, Calgary, Alta. T2L 2A7

T.B.W. Baker, National Research Council of Canada,

Ottawa, Ont. KIA OR6 Div. of Bldg. Research,

L.A. Balanko, EBA Engineering Consultants Ltd. 14535 - 118th Ave. Edmonton, Alta. T5L 2M7

Environmental Assessment Div. D.M. Barnett,

Dept. of Indian Affairs L Northern Development, Ottawa, Ont. KIA OH4

V. Batozski, USSR, Donetsk, Sheljskintseistz, 151, U.S.S.R.

H.T. Beare, Dept. of National Defence, Def@nce Research Est. Suffield Ralston, Alta. TOJ 2N0

Govt. of QuPhec O.P.D.Q., L. Beaulieu,

QuGbec, pub. 1050 St. Augustin,

R. Bednar, Mobile Augers & Research, 5736 - 103A St., Edmonton, Alta.

P. Bellair, 25, rue de 1'Yser. 92330 SCEAUX, France

R. Berg, USA CRREL P.O. Box 282, Aanover, N.H. 03755

G.W. Bernard, Geotechnical Consultant,

Edmonton, Alta. T6G OE3 11641 - 73 AVe.

W.F. Bernard, Dome Petroleum Ltd.

Calgary, Alta. T2P 2H8

M. Berry, Arctic Meteorolosv Section (RCCA)

P.O. BOX 200,

Environment Canada, 4905 Dufferin St. Downsview, Ont. M3H 5T4

J. Bertok,

Transport Canada, Airport Facilities Br.

Transport Canada Bldg.,

Ottawa, Ont. KIA ON8 20thF1. KFSA,

Dept. of Botany, University of Alberta, Edmonton, Alta. T6G 2H4

J. Bourbonnais, kcole Polytechnique, Chambre B-338, C.P. 6079, Succ. A, Montrial, P . Q . H3C 3A7

M.C. Brewer, USGS National Petroleum, Reserve in Alaska,

Anchorage, AK 99503 2525 "C" S t . , Suite 400,

B. Breymann, National Academy of Sciences,

Washington, D.C. 20006 1730 Pennsylvania Ave. N.W.,

0. Brody, Associated Eng. Services Ltd.

Edmonton, Alta. TSL 4R8 13140 St. Albert Trail,

D.E.G. Bromley, James F. MacLaren Ltd.

Edmonton, Alta. 10240 - 124th St. Suite 608,

J. Brown,

P.O. Box 282, Banover, NH 03755

USA CRREL,

R.J.E. Brown, National Research Council of Canada,

Ottawa, Ont. KIA OR6 Div. of Building Research,

D. Brunnschweiler, Dept. of Geography, Michigan State University, East Lansing, MI 48824

A. Bruno, Cerrito 1248 Buenos hires, 1010 Argentina

C. Burrous, QUatetnaty Res. Center, AK-60, University of Washington, Seattle, WA 98195

R.E. Byers, Foothills PiPFlineS ( S . Yukon) 1600 BOW valiey SQ IT, 205 - 5th Ave. S.W.. Calgary, Alta. T2P 2W4

J. Cameron, Northern Technology Centre, Environment Protection Service

Edmonton, Alta.

8. Cammenga-Knol, Shell Development Co., "2560,

Houston, TX 77001

9942 - 108 St.,

P.O. BOX 1380,

24 8

D.S. Campbell,

Technical Services Div. Iron Ore Co. of Canada,

Sept-lles, P.Q.

J.E. Campbell, U.S. Dept. of Interior (PWS) 18th 6 c streets NW, Washingt-on, D.C. 20240

Chevron Research Co. R.W. Campbell,

P.O. BOX 1627, Richmond, CA 94802

J. Cannon, Northwest Alaskan Pipeline Co.

Salt Lake City, UT 84110 P.O. Box 1526,

J.D. Card, Sun Oil Co. Ltd. P.O. Box 3 8 , Calgary, Alta. T2P 2V5

Associated Eng. Services Ltd. E.I. Carefoot,

13140 St. Albert Trail, Edmonton, Alta. T5L 4R8

100 Retty S t . .

L.E. Carlson, Foothills Pipe Lines (Yukon)

Calgary, Alta. T2P 2W4

M. Carnogursky, CARN Construction Ltd. Box 2050, Inuvik, N.W.T. XOE OTO

C. Catlin, British Gas Corp. London Research Station, Michael Rd.

1600 - 205 - 5th Ave. S.W.

London, 11K SW6 2AD

E.J. Chamberlain, U.S. Army CRREL

Hanover, NH 03755 P.O. Box 2 8 2 ,

L. Chambers, Techman Ltd.

Calgary, Alta. T2P 2 ~ 7 3 2 0 - Seventh Ave. S.W.

E.C. Chandler, Alaska Dist., Corps of Engrs. P.O. Box 7002, Anchorage, AK 99510

P.K. Chatterji, Thurber Consultants Ltd. 10509 - ElSt Ave. Edmonton, Alta. T6E 1x7

S.C. Chatwin, Dept. of Geology, University of Alberta, Edmonton, Alta. T6G 2H4

K.C. Cheng,

University of Alberta, Dept. of Mechanical Eng.

Edmonton, Alta. T6G 2G8

K.T. Cheng, Glaciology c Cryopedology Inst. Lanchow Academie Sinica, The People's Republic of China.

M.S. Cheung, Public works Canada,

Ottawa, Ont. KIA OM2 7E Sir Charles TUpper Bldg.

A. Chizkov,

Geological Fakvltet kaf USSR Moskov Leninsky Gori Univ.

Merslotovedenia U.S.S.R.

E.A. Christiansen, E.A. Christiansen Consulting Ltd. Box 3087, Saskatoon, Sask. 57K 3S9

L. Christensen, Inst. of Geology, University of AARHU5, Universitcts Parken, DK-8000 Aarhus C, Denmark.

H.S. Chu, Highway Design Inst. Ministyry of Communications, Peking, People's Republic of China

J. Clague, Geological Survey of Canada, 100 West Pender St. Vancouver, B.C. V5w 1C4

J. Clark, R.M. Hardy 6 Associates, 910, 205 - 5th Ave. S.W., Bow valley square TI, Calgary, Alta. T2P 2WS

M. Clark, Crowley Maritime Corp., Box 2287, Seattle, WA 98111

E. Clarke, Clarke Engineering Co. Box 80891. Fairbanks, AK 99708

R. Cole, Chevron Standard Ltd. 652 Wilderness Dr. S.E. Calgary, Alta. T2J 122

L. Colie, Transport Group,

University oE Waterloo, Dept. of Civil Engineering,

Waterloo, Ont.

R.D. Cook, Public Works Canada, P.O. Box 488, Edmonton, Alta.

D.M. Coulter, Royal Military College, Kingston, Ont. K7L 2W3

D.W. Cowell,

Canada Centre for Inland Waters, Lands Directorate,

Box 5050, Burlington, Ont. L7R 9A6

D.B. Craig, Dept. of fndian & Northern Affairs,

Whitehorse, Yukon Y1A 4MB 200 Range Rd.

C.B. Crampton,

Simon Fraser university, Dept. of Geography,

Burnaby, B.C. V5A 1s6

F.E. Crory,

Hanoever, NH 03755

C. Cuddy, Dept. of Indian & Northern Development, Box 1824, Inuvik, N.W.T. XOE OTO

Mobile Augers & Research, D. Currie,

5736 - 58 Ave. Edmonton, Alta.

J . R . Davie, McClelland Engineers Inc., 6100 Hillcroft, Houston, TX 77081

400 Rip Rd.

J.L. Davis, Geological Survey of Canada,

Ottawa, Ont. KIA OE8 601 Booth St.

D.M. Davison, Klohn, Leonoff Consultants Ltcl.

Calgary, Alta. T2P OA5 140 - 1 Ave. 5.w.

D.W. Davidson,

Canada, Div. of Chemistry, National Research Council of

Ottawa, Ont. KIA OR^

L.L. De Goes, National Academy of Sciences,

Washington, DT: 20418 2101 Constitution Ave. N.W.

J.R. Delapp, Alaska Native Health Service,

Anchorage, AK 99501 3350 Commercial Drive,

D.W. Devenny, EBA Engineering Consultants Ltd.

Edmonton, Alta. T5L 2 ~ 7

V. Deviatkin, USSR 677010 Jakutsk, Permafrost Institut, U.S.S.R.

J.C. Dianne, Environnement Canada, C.P. 10100,

14535 - 118 AVe.

QuBbec, P.Q. G1V 4H5

A. Draklin, USSR State Committee for Science

MOSCOW. Gorkii St 13, and Technology,

U.S.S.R.

Dr. Dubicov, USSR MOSCwa, Okrujnoy pz. 18 Pniiis, U.S.S.R.

R.J. Eager, 46 Weir Cres. Saskatoon, Sask. S7H 3A9

Terrain Sciences Div. P . Egginton,

Geological Survey of Canada,

Ottawa, Ont. KIA O E ~ 601 Booth St.

M.K. El-Defrawy, Non-Renewable Resources Br.

10 Wellington St. Indian Affairs & Northern Develop.

Ottawa, Ont.

K.E. Eliason, Frank Moolin 6 Associates Inc.

Anchorage, AK 99503 3201 C Street, Suite 600,

E. Eltchaninow,

Octyabrsky p 2 352, Korp 6 5 U.S.S .R. Lubertsj Moskowskaj,

U.S.S.R.

T. Ersoy, Site 3 , Box 4, Yellowknife, N.W*T. XOE 180

D.C. Esch, Alaska Dept. of Transportation

P . O . BOX F, Research Lab,

Fairbanks, AI( 99708

P.L. Essley, U,S, Government, Federal Energy Regulatory Commission,

Washington. wA 20426 941 North Capital St. N.E.

249

K.R. Everett, Institute of Polar Studies, The Ohio State University 125 South Oval Mall, Columbus, OH 43210

R.E.K. Feilden, Associated Engineering Services Ltd. 13140 St. Albert Trail, Edmonton, Alta. T5L 4R8

M.M. Fenton, Alberta Research Council,

Edmonton, Alta. T6G 2C2

0.J. Ferrians Jr. U.S. Geological Survey,

Menlo Park, CA 94025 345 Middlefield Rd.

D.E. Fielder, Foothills Pipelines (S. Yukon) Ltd.

Calgary, Alta. T2P OT5 635 - 6 AVe. S.W.,

J.R. Finley, Dames & Moore, 510 L Street Suite 310. Anchorage, AK 99501

W.D.L. Finn, Dept. o f Applied Science University of British Columbia,

Vancouver, B.C. V6T 1W5 2075 Westbrook Place,

R.J. Fletcher, Dept. of Geography, University of Lethbridge, Lethbridge, Alta. T1K 2C8

C. Fooks, Foothills Pipe Lines,

Calgary, Alta. T2P 2w4 1600 - 205 5 Ave. S.W.

11315 - 87 AVe.

C.D. Forbes, Public Work$ Canada, 9925 - 109th St. P.O. Box 488, Edmonton, Alta. T5f 2 ~ 1

K. Francis, BOX 993, Eagle River, Alaska, AK 99577

H.M. French, Dept. OE Geography & Regional Planning, University of Ottawa 74 Laucier St. E. Ottawa, Ont. KIN 6N5

J. J. Fridfinnsson, CN Telecommunications

Toronto, Ont. M5J 1G1 151 Front St. w.

Y. Fujii, National Inst. of Polar Research

Tokyo 173, Japan 3-10 Kaga, 1-chome, Itabashi-ku

S.P. Fuller, Dept. of Geography, University o f British Columbia

Vancouver, B.C. V6T 1W5 2075 Wesbrook Mall,

J .A . Fullerton, Dept. of Public Works of Canada, Sir Charles Tupper Bldg.,

Ottawa, Ont. K ~ A OM2 Riverside Drive,

J.G. Fyles, Indian Affairs L Northern Development 813, Terra8SeS de la Chaudihre Ottawa, Ont. KIA OH4

W.R. Galatiuk, Foothills Pipe Lines (Yukon) Research Inst., Fack,

Calgary, Alta. T2P 2W4 1600 - 205 - 5 Ave. S.W.,

R. Gandahl, National Swedish Rd. & Traffic Research Inst. Fack, 58101 Linkoping, Sweden.

Dept. of Civil Engineering, P. Gaskin,

Queen's University, Kingston, Ont. K7L 3N6

M. Gavzilova, USSR, 677010 Yakutsk, 10, Inst. Mezzlotovedenia, AN SSR, USSR

Dept. of Geography, D. Gill,

The University of Alberta Edmonton, Alta. T6G 2H4

K.R. Gillespie, Klohn Leonoff Consultants Ltd.

Calgary, Alta. T2P OA5 140 - 1st Ave. S.W.

University of Alberta, R.R. Gilpin,

Edmonton, Alta. Dept. of Mechanical Eng.,

P. Gimbarzevsky, Environment Canada, Forest Management Inst.

Ottawa, Ont. K1G 326 396 Cooper St.

R.D. Goff, Sohio Petroleum Co. 100 Pine St. San Francisco, CA 94111

L.w. Gold, National Research Council of Cana Div. oE Building Research, Ottawa, Ont. KIA OR6

A. P . Gorbunov, USSR 677010 Permafrost Institute, Yakutsk, U.S.S.R.

G. Gorskaya, E-58 Okruznoy projasd 19 Scientific Research Pipeline Inst U.S.S.R.

M.A. Goodman, Enertech,

Houston, TX 77098 2727 Kirby Dr. Suite 201,

National Research Council of Cana L.E. Goodrich,

Div. of Building Research, Ottawa, O n t . KIA OR6

S . Gotoh, Plant Construction Div. Production and Engineering Dept. Tokyo Gas Co. Ltd. 2-16 Yaesu 1-chome Chuo-ku, Tokyo, Japan.

A.D. Gould, Templeton Engineering,

Winnipeg, Man. 966 Waverly St.

C.A. Graham, EBA Engineering Consultants Ltd. 14535 - 118th Ave. Edmonton, Alta. T5L 2M7

N. Grave, Perma.fr0e.t Inst. of Academy of Science of the U.S.S.R. Yakutsk 10, U.S.S.R.

O.S. Gregersen. Norwegian Geotechnical Inst.

Taasen, Oslo 8, Norway

P.O. nox 4 0 .

G. Gryc, U.S. Geological Survey, ONPRA, 345 Middlefield Rd. Menlo Park, CA 94025

I. Guryanow, USSR Yakutsk 10, Permafrost Institute, U.S.S.R.

W. Haas, 901 Agate St. Houghton, MI 49931

W. liaeberli,

water Resources DiV., US Geological Survey,

Project Office-Glaciology 1201 Pacific Ave. Quite 1850, Tacoma, WA 98402

E. Ha1le.t.

Stanford University, Dept. of Applied Earth Sciences

Stanford, CA 94305

L.E. Hamelin, UniversitP Laval, Centre d'btudes Nordiques QuPbec, P.Q. G1K 7P4

T.O. Hanley, campion College, university of Regina, Regina, Sask. 545 OA2

A.J. Hama, R.M. Hardy & Associates Ltd.

Calgary, Alta. 219 - 18 St. S.E.,

d.M. Hardy, R.M. Hardy & Associatcs Ltd.

Edmonton, Alta. T6G 127 11615 EdinbOrO Rd.

W. Harms, Chevron Standard Ltd. 400 - Fifth Ave. S.W. Calgary, Alta. T2P OL7

J . R . Harper, Coastal Studies Inst. Louisiana State Univ. Baton Rouge, LA 70803

M.C. Harris, Thurber Consultants Ltd.

Edmonton, Alta. T6E 1x7 10509 - 81st Ave.

S . A . Harris, 6316 Dalton Dr. Calgary, Alta. T3A 1E4

W.D. Harrison, Geophysical Inst. University of Alaska, Fairbanks, AK. 99701

Trigg, Woollett Consultant Ltd. F.R. Hassard,

10504 - 103 St. Edmonton, Alta.

G.T. Haugan, U.S. Dept. of Transportation

Materials Transp. Bureau Res. & Special Programs

Office of the Alaska Pipeline

Washington, D.C. 20590 2100 2nd St. S.W.

R.K. Haugen,

Box 2 8 2 , USA CRREL

Hanover, N.H. 03755

250

Arctic Geotechnical GKOUV D.W, Hayley,

EBA Engineering Consultaits Ltd. 14535 - 118 Ave. Edmonton, Alta. T5L 2 ~ 7

D. HayneS, USA CRREL P.O. Box 282, Hanovet, N.H. 03755

J.A. Heginbottom, Geological Survey of Canada, 601 Booth St. Ottawa, Ont. XIA OEB

R.A. Hemstock, R.M. Hardy & Associates Ltd., 1011 Royal Ave. S.W. Calgary, Alta.

J. Henderson. R.M. Hard &-Associates Ltd., 213 - 1st' St. S.E. Calgary, Alta.

J.B. Henry, Kenting Exploration Services Ltd. 5636 Burbank Cres. S.E. Calgary, Alta. T2H 126

J. Hermstad, A/S Geoteam, Wm. Thranesgt 98 Oslo, Norway

L. HettingeK,

910 205 5vh Ave. S.W. Calgary, Alta. T2P 2W5

EXxOn Production Research Co. C.E. HeUer,

Houston, TX 77001 P.O. Box 2189,

R.M. Hard & Associates Ltd.

D. Hill, Arctech Resource Management Services, P.O. Box 1070, Inuvik, N.W.T. XOE OTO

C.K. BO,

Chintao, Heilungkiang Province Permafrost Experimental Station

P@ople's Republic of China

C.L. HO, 12257 Lake Erie Rd. S.E. Calgary, Alta. T2J 223

G.D. Hobson, Energy, Mines & Resources, Polar Continental Shelf Project 880 Wellington St., Ottawa, Ont.

P. Hoekstra, R.M. Hardy & Associates Ltd.

Calgary, Alta. 310 BOW Valley Square 11,

J.E.F. Hoggan, Hoggan Engineerinq & Testing Ltd. 8803 - 5 0 Ave. Edmonton, Alta. T6E 5H4

K. Holden, U.S. Geological Survey,

Anchorage, AK 99501 800 A St. Suite 109,

G. Hollingshead, R.M. Hardy & Associates

Edmonton, Alta. TSS ZL4 4810 - 9 3 St. P.0. BOX 746

G.L. Hood, Panarctic Oils Ltd. P.0. Box 190, 703 - 6th Ave. S.W. Calgary, Alta. T2P 2 ~ 6

S. Hopke, Exxon Production Research Co. P.O. Box 2189 , Houston, TX 77001

K. Horiguchi, Inst. of Low Temperature Science University of Hokkaido Sapporo, Japan 060

J.D. Howell, Beak Consultants Ltd.

Calgary, Alta. T2E 6M7

J.C. Hudson, Public Works of Canada, 201 Range Rd. Whitehorse, Yukon Y1A 3A4

D.M. Hopkins, US Geological Survey, 345 Middlefield Rd.

3530 - 11 A St. N.E.

Menlo Park, CA 94025

O.L. Hughes, Terrain Sciences niv. Geological Survey of Canada

Calgary, Alta. T2L 2A7

V.E. Hume, Indian & Northern Affairs, Le6 Terrassess de la Chaudi5re 6th Floor, North Tower, Hull, Qud. KIA OH4

P. Hunt, University of Calgary,

Calgary, Alta. DePt. of Geography,

J.A. Hunter, Geologicval Survey of Canada, Inuvik Research Lab. Box 1430, Inuvik, N.W.T.

W.T. Hushen, National Academy of Sciences, Polar Research Board 2101 Constitution Ave., Washington, D.C. 20418

C.T. Hwang, EBA Engineering Consultants Ltd.,

Edmonton, Alta. T5L 2M7 14535 - 118 Avenue,

M. Iguro, Civil Engineering Dept. The Shimizu Construction Co. 16-2 Kyobashi Chuo-ku, Tokyo, Japan

J.T. Inglis,

Northern Environmental Indian L Northern Affairs

Protection ~ r . Environmental Studies Division, Ottawa, Ont. KIA OH4

R. Innes, Mobile Augers & Research, 5736 - 5 8 Ave. Edmonton, Alta.

S.B. Xnstanes, Storetveitvegen 96, 5032 Minde/Bergen, Norway

3303 - 33rd St. N.W.

USA. CRREL, I. Iskandar,

P.O. BOX 282, Hanover, N.H. 03755

G. Jacobsen, The Tower Co. (1961) Ltd.

Montreal, P.Q. H3G 1K1 1390 sherbrooke W. Suite 15,

H.O. Jahns, Exxon Production Research Co.

Houston, T X 77055 P.O. Box 2189,

F. James, Chief Engineer, Dept. of Public Works, Govt. of the NWT Yellowknife, NWT

J.A. Janovjak CN Telecommunications, Engineering Dept. o/P 151 Front St. W. Toronto, Ont. M5J 1G1

H.Y. Jao, The Scientific Research

Peking, Peoples' Republic of China, Inst. of the Communication Ministry

A. Jenkins,

P.O. Box 90, Polar Gas Project,

Commerce Court W. Toronto, Ont. M5L 1H3

€I. Jensen, Associated Eng. Services Ltd.

Edmonton, Alta. T5L 4R8 13140 St. Albert Trail,

Dept. Of Civil Enqineering, H.L. Jessberger,

P.O. Box 102148, Ruhr-University Bochum,

4630 Bochum 1, Fed. Republic of Germany.

Morrison, Hershfield, Burgess A.B. Johns,

and Huggins Ltd. 3089 Bathurst St. Toronto, Ont. M6A 2A4

G.E. Johns, Federal Highway Administration P.O. Box 1648 Juneau, AK 99802

L.R. Johnson, USA CRREL, US EPA Arctic Research Lab, College, AK 99701

P . R . Johnson, USA CRREL Ft. Wainwright, AK 99701

USA CRREL T.C. Johnson,

P.O. BOX 282, Hanover, N.H. 03755

G.H. Johnston, National Research Council Div. of Building Research Ottawa, Ont. KIA OR6

Glaciology Div. S . J . Jones,

Inland waters Directorate Environment Canada, 562 Booth St. Ottawa, Ont. KIA OE7

L.C. Jordan, Northern Studies Center, Box 610 , Churchill, Man. ROB OEO

A.S. Judge, R . R . NO 3 , North Gower, Ont. KOA 2T0

A.R. Jumikis,

Piscataway, N.J. 08854 817 Hoes Lane,

D.L. Kane, Institute of Water Resources, University of Alaska, Fairbanks, AK 99701

25 1

J. Karte,

Geographisches Institut RUhK universitat Bochum,

universitats Str 150, Bochum 1, Federal Republic of Germany

B.D. Kay,

University of Guelph, Dept. of Land Resource Science

Guelph, Ont.

J.N. Keen, Keen Engineering Co. Ltd.

West Vancouver, B.C. 214 - 545 Clyde Ave. V7T 1C5

D.E. Rerfoot.

Assessment Br. Integration L Environmental

Environmental Management Service Fisheries L Environment Ottawa, Ont. KIA OE7

G.P. Kershaw, Dept. of Geography, university of Alberta, Edmonton, Alta. T6G 2H4

M. Kinash, Associated Engineering Services Ltd. 13140 St. Albert Trail, Edmonton, Alta. T5L 4R8

M.S. King, Dept. of Geological Sciences Univ. of Saskatchewan, Saskatoon, Sask. S7N Ow0

S . Kinoeita,

Hokkaido University, Inst. of Low Temperature Sc.

N 19 W 8 , Sapporo, Japan 060.

M. Kiriak,

Edmonton, Alta.

L. Kiss.

11925 - 37 St.

Edmonton, Alta. T6B 2G3

K. Klebba, Northwest Alaskan Pipeline Co. P.O. Box 1526, Salt Lake City, Utah 84110

R.M. Kliewer, Brown & Root Inc. P.O. Box 3, Houston, TX 77001

. ..

I. Klimovski, USSR 677010 Yakutsk, Permafrost Institute, U.S.S.R.

T.W. Klym, Ontario Hydro, 800 Kipling AVe. Toronto, Ont.

3 . Krahn, Dept. of Civil Engineering, Univ. of Saskatchewan, Saskatoon, Sask. S7N Ow0

V . Kubetsky, Moscow USSR 117114 Moscow Civil Engineering Inst., Shluzova Naberezna 8, U.S.S.R.

W.O. Kupsch,

university of Saskatchewan Dept. of Geological Sciences

Saskatoon, Sask. S7N OW0

P.J. KUTfUrYt, Geological Survcy of Canada, 601 Booth St. Ottawa, Ont. KIA OE8

B. Ladanyi, &ole Polytechnique, uept. of Civil Engineering, C.P. 6079, Station A , Montrial; P . Q . H3C 3A7

G.R. Lange, 7449 Bailey Drive, Anchorage, AK. 99502

8 . Lanz, Fluor Irvine, E & C, SCD 3333 Michelson D r . Icvine, CA 92730

A.D. Laplante, Underwood McLellan (1977) Ltd. 16 Scarboro Place, St. Alhert, Alta. T8N OH8

D.B. Larson, Lawrence Livermore Lab. L-205. P.O. BOX 808, Livermore, CA 94550

National Energy Board, D.E. Lawrence,

473 Albert St. Rm. 340, Ottawa, Ont. KIA OE5

Associated Engineering Services Ltd. N.A. Lawrence,

13140 St. Albert Trail, Edmonton, Alta. T5L 4RB

H.R. Lee, DOWL Engineers 4040 "B" St. Anchorage, AK 99503

R.F. Legget,

Ottawa, Ont. RIS 1N7 531 Echo Drive,

R. Lewellen, Lewellen Arctic Research P.O. Box 2434, Littleton, CO 80161

S.H. Li, China Society of Civil Eng. Pekinq, People's Republic of China

Y.S. Li, Res. Inst. of the Ministry of Railways, Peking, People's Republic of China

T. Lianq, Cornel1 University, HolliSteK Hall, Ithaca, N.Y. 14853

A.E. Liguori, Exxon Research & Engineecinq Co. Florham Park, NJ 07932

Woodward-Clyde Consultants, G. Linkletter,

Oranqe, CA 92668 P.O. Box 1149,

L.E. Lindsay, Earth Science Dept. Ilniversity of Waterloo, Waterloo, Ont.

K.A. Linell,

HanoVeK, N.H. 0 3 7 5 5 4 6 Rip Rd.

G.B. Lipsett, Foothills Pipelines Ltd. 1600 Bow Valley Square I1

Calgary, Alta. T2P 2W4 205 - Sth Ave. S.W.

A. Liron, Caulfield - Liton Consultants Ltd. Edmonton, Uta. T6B OE6 5208 - 82 Ave.

H. Livingaton, Dept. of Transportation & Public Facilities, State of Alaska,

Fairbanks, AK 99701 2301 Peger Rd.

T. Lloyd, ASSOC. of Cdn. Univ. for Northetn Studies, 130 Albert St. Suite 1208, Ottawa, Ont. KIP 564

E.F. Lobacz, USA CRREL

Hanover, N.H. 03755 P.O. BOX 282

J.G. Locker, School of Engineering Lakehead University, Thunder Bay, Ont.

Arctic Foundations Inc., E.L. Long,

6613 Arctic Blvd., Anchorage, AK 9 9 5 0 2

S.R. Loomis, 4 6 Glenhaven Crescent, St. Albert, Alta. TEN 1A5

N. Lopoukhine, Lands Directorate, EMS, DFE P.O. Box 365, Halifax, N . S . 533 2P8

B.H. Luckman, Dept. of Geography, Univ. of Western Ontario London, Ont. N6A 3C5

P. Lukomskyj, 15108 - 51 Ave. Edmonton, Alta. T6H 5C1

V . Lunardini, Dept. of Mechanical Eng. University of Ottawa, 770 King Edward St. Ottawa, Ont.

D.P. Lusch, 328 N. Hayford, Lansing, MI 48912

G. Maarleveld University of Amsterdam, Kerkweg 5 6 , Prot. Maarlcvsld, 6713Nu Ede Gld. Holland

H . MacAulay,

Ottawa, Ont. K2H 5N9 39 HarLowe Cres.

R . MacCallum, Suite 5 0 0 , 404 - 6th AVe. S.W. Calgary, Alta. T2P OR9

J.R. MacDonald Imperial Oil Ltd. 500 - 6th Ave. S.W. Calgary, Alta. T2P OS1

K.L. MacInnes, Land RCSOUTCeS Section

Affairs, P.O. BOX 1500, Dept. of Indian 6 Northern

Yellowknife, N.W.T. Y1A 2R3

J.R. Mackay, Dept. of Geography,

Vancouver, B.C. V6T lw7 Univ. of British Columbia,

Canadian Bechtel Lt,d. I.H. MacLachlan,

Toronto. Ont. M4W 3K5 250 BlOOr St. west,

252

D. Mageau, Dept. of Civil Enqineering, University of Alberta, Edmonton, Alta. T6G 2G7

L.J. Mahar, Fugro Gulf Inc.

Houston, TX 77036 8181 Commerce P1. Dr. Suite 712

D . Maishman, Freezewall Inco. Box 316 - 1OC Stickle Ave. Rockaway, N.J. 07866

W.K. Mak, Engineering 6 Architecture Br.

Ottawa, Ont. KIA OH4 Dept. of Indian & Northern Affairs

L. Maksimova, USSR Moskow Leninsky Gori Univ. U.S.S.R.

W.L. Mansell,

Edmonton, Al.ta. T6C 4G3 4920 76 Ave.

R.G. Mantion Arctic & Subarctic Res. Service P.O. Box 8889 Montreal, P.Q. H3C 3P8

J.A. Maple, Alyeska Pipeline Service Co.

Anchorage, AK 99512 1835 So. Bragaw

P. Marsh, 90 Elmwood Ave. Willowdale, Ont. M2N 3 ~ 9

Public Works Canada D. Matthews,

201 Range Rd. Whitehorse, Y.T. Y1A 3A4

A. McCann, EPEC Consulting Western Ltd. 4437 - 99 st. Edmonton. Alta. T6E SB6

G. McCormick, R.M. Hardy 6 As6oc. Ltd.

Edmonton, Alta. T5N ON9 13607 - 102 Ave.

G. McCulloch, Fisheries & Environment Canada Inland Waters Directorate Water Survey o f Canada 521 - 269 Main St. Winnipeg. Man. R3C 182

J.C. McDougall,

Box 305, Imperial Oil Ltd.

Redwater, Alta.

J.R. Mcoougall, The Dalcor Group,

Edmonton, Alta. T5J 1v9 10080 Jasper Ave. NO 1100,

F. McFall, Crowley Maritime Corp. Box 2287, Seattle, WA 98111

R. McGaw, USA CRREL P.O. Box 282, Hanover, N.H. 03755

Dept of the Navy, R.K. McGregor,

Office of Naval Research

Arlington, VA 22217 800 N. puincy St, Code 461

J.D.H. McMillan,

P.O. Box 2844, Petro-Canada

Calgary, Alta. T2P 2M7

D. McNeill, Geonics Ltd.

Mississauga, Ont. 1745 Meyerside Dr.

L5T 1C5

E.C. McRoberts, R.M. Hardy & Assoc. Ltd., 7611 - 143A St. Edmonton, Alta. T5R OP8

U.S. Dept. o€ the Interior - BLM R.L. Means,

18th 6 c Streets, w, Washington, D.C. 20240

Academy of Sciences of the USSR P.I. Melnikov,

Yakutsk, U.S.S.R. Permafrost Institute,

V. Melnikov, USSR 677010 Yakutsk - 10, Institut U.S.S.R.

Merzlotovedeniva

J. Merkt, Niedersachs, Landesamt f . Bodenforschung, Postfach 510153

west Germany D-3 Hannover - 51

F.A. Michel, Dept. of Earth Sciences university of Waterloo waterloo, Ont. N ~ L 3 ~ 1

Golder Associates B.W. Mickleborough,

Calgary, Alta. T2H 1K3

Rarding-Lawson Associates D . Miller,

Anchorage, AK 99502

J.D. Miller, Geotechnical Sciences Lab.

Carleton University, Dept. of Geography

Ottawa, Ont. K ~ S 5 8 6

R.D. Miller,

Cornell University, Dept. of Agronomy,

Ithaca, N.Y. 14853

B.Y. Milner, Beak Consultants Ltd.

Calgary, Alta. T2E 6M2 3530 - 11A Street N.E.

A. Mindich, 7067 N. Ashland, Chicago, IL 60626

J .D. Mollard, J.D. Mollard 6 ASSOC. Ltd.,

Regina, Sask. 815 McCallum-Hill Bldg.

E. Moniz, R.M. Hardy & ASSOC. Ltd.,

P.O. Box 746, 4810 93 St.

Edmonton, Alta. T5J 2L4

J. Morack,

5915 - 3rd St. S.E.

624 W. Int'l. Airport Rd. NO. 10

Geophysical Inst. Physics uept. University of Alaska, Fairbanks, AK 99701

N.R. Morgenstern, Dept.of Civil Engineering, University of Alberta, Edmonton, Alta.

W.C. MOyle,

Juneau, AK 99803 Route 6 , Box 6188,

F. Muller, Cerrito 1248 Buenos Aires, 1010 Argentina.

K. Mullerbeck,

Don Mills, Ont. M3C 1y9 29 Gervais Drive

A.D. Myska, Templeton Engineering Co.

Winnipeg, Man. R3T 4M5 966 Waverley St.

n. Naylor, Dept.'of Public works, Govt. of the NWT Yellowknife, NWT

K.G. Neave,

Energy Mines & Resources Canada, Polar Continental Shelf Project,

Ottawa, Ont. mn. 109, 401 Lebreton St.,

E. Nechaev, USSR 677010 Yatkutsk 10, Inst. of Permafrost, U.S.S.R.

F. Nelson, Dept. of Geography, The Univ. of Michigan, 4015 LS & A B l d g . , Ann Arbor, MI 48109

Environment Canada, R.W. Newbury,

Fisheries & Marine, Freshwater In

Winnipeg, Man. R3T 2N6 501 university Cres.,

J.F. Nixon, R.M. Hard & Assoc. Ltd.,

Calgary, Alta. 219 - 18tx St. S.E.,

E. Nyland, Northern Affairs Program,

Whitehorse, Yukon Y1A 3V1 200 Range Rd.,

M.J. O'Connor, 5664 Burleigh Cres. S.E., Calgary, Alta. T2H 128

T. Ohrai, Seiken Co. Ltd., Auto-Center Bldg. No 6 8 , 3-Bancho Kawarayamachi, Minami-ku Osaka, Japan.

G.R. Olhoeft, U.S. Geological Survey, Box 25046 Federal Center MS 964 Denver, CO 80225

H.G. Oliver, Petro-Canada, P.O. BOX 2844, Calgary, Alta. T2P 2M7

J. Olson,

Emonton, Alta. 10636 - 85 Ave. Apt. 7,

K. Ono, Konoike Const. Co. Ltd, 27 4-chome Kitakyuhoji-Machi, Hiqashi-ku, Osaka, Japan 541.

T.E. Osterkamp, Geophysical Inat. University of Alaska, Fairbanks, AK 99701

S . I . Outcalt, University of Michigan, Dept. of Geography, Ann Arbor, M I 48109

253

B.I. Pandit, Dept. of Geological Sciences univ. of Saskatchewan, Saskatoon, Sask. S7N OW0

V.R. Parameswaran, National Research Council of Canada, Div. of Bldg. Research. Ottawa, Ont. KIA OR6

W.B. Parker, Federal State Land use Planning Commission FOT Alaska,

Anchorage, AK 99501 733 West 4th Suite 400,

D.G. Paton,

Edmonton, Alta. T5W 4R3 521 Abbottsfield Rd.

Westbay Instruments Ltd.

Vancouver, B.C. 2-265 25th St. west

T.S. Penfold, Southern California Gas Co., P.O. Box 3249 - Terminal Annex, Lo6 Angeles, CA 90051

P.S. Penland, Dept. of Geography, Louisiana State univ., Baton Rouge, LA 70803

E. Penner , Canada, Div. of Bldg. Research, National Research Council of

Ottawa, Ont. KIA OR6

E. Perfect, 1174 Belanger Ave., Ottawa, Ont.

N.M. Peterson, Western Ecological Services Ltd. 211 - 11 Fairway Drive, Edmonton, Alta. T6J 2W4

w. Pettapiece,

F.D. Patton,

Agtic. Canada - Soil Survey, 14605 118 AVe.. Edmonton, Alta. T5L 2M7

T.L. P6w6

Arizona State university Dept. of Geology

Tempe. A2 85281

A + Phukan, Civil Engineering Dept. University of Alaska Fairbanks, AK 99701

C.T. Pi,

of Railways, Res. Inst. of the Ministry

Peking, People's Republic of China

Centre de Recherche pour la D.R. Pichette,

Ottawa, Ont. KIA 0 2 4 Difense, Shirley's Bay,

J . A . Pilon, Centre de Recherches pour la

CRDO, Vehicle Mobility Section, Difense,

QGDN, 101 Colonel By Dr., Shirley's Bay,

Ottawa, Ont. KIA 024

E. Polloway, Techman Ltd.,

Calgary, Alta. T2P 2M7 320 Seventh Ave. S.W.,

K . G . Priesnitz, Dept. of Geography, University of Gottingen, Goldschmidt Str. 5,

Federal Republic of Germany 34 Gottingen,

P.A. Prince, Dept. of Geoscience, Indiana Univ. of Pennsylvania, Indiana, PA 15701

0. Pufahl, Dept. of Civil Eng., University of Saskatchewan, Saskatoon, Sask. 57N OW0

N.K. Pui, Dome Petroleum Ltd., P.O. BOX 200, Calgary, Alta. T2P 2H8

E. Ramanjaneya, Fugro Xnc., 3177 Long Eeach Blvd., P.O. Box 1765, Long Beach, CA 90807

M. Raymont, Sulphur Development Inst. of Canada, 830 Bow Valley $ 4 . 1, 202 6th Ave. S.W., Calgary, Alta.

D.E. Reid, R.M. Hardy 6 Associates, 402 16A St. N.W.. Calgary, Alta. T2N 2C8

R. Reid, Mechanical & Aero. En9. Dept., university of Tennessee, Knoxville, TN 37916

Mail Stop AK-60, R.G. Rein Jr.,

university of Washington, Seattle, WA 98195

R.J. Rennie,

Curtis Eng. L Testing 216 - 35 Ave. N.E.

Calgary, Alta. T2E 2K5

E.F. Rice, University of Alaska, S.R. 20098 Fairbanks, AK

J. Rodney. Construction Services Br. Ministry of Transport 9820 107 St. Edmonton, Alta. T5K 1G3

J.C. Rogers, Engineering Dept. University of Alaska, 3221 Providence Dr. Anchorage, AK 99504

W.D. Roggensack, Arctic Geotechnical Group EBA Engineering Consultants Ltd. 14535 - 118 AVe. Edmonton, Alta. T5L 2M7

E. Romanov, Leningrad LENZNIIEP U . S . S . R .

N. Romanovskiy Permafrost Dept. Faculty of Geology, Moscow 117234 U . S . S . R .

W.A. Rouse, Dept. of Geography MCMaSter University, Hamilton, Ont.

W.G. Rowan, Transport Canada Res. 6 Development Centre 1000 Sherbrooke St. w. P.O. Box 549 Montreal, P.Q. H3A 2R3

B . E . Ryden, Hydrological Div. Dept. of Physical Geography The University of Upsala P.O. Box 554 S-751 22 Upsala, Sweden.

W.M. Sanders, Bechtel Incorporated P.O. Box 3965 San Francisco, CA 94119

R.H.B. Sangster, Imperial Oil Ltd. Production Research Div 3 3 9 50 Ave. S.E. Calgary, Alta.

K.w. Savigny Dept. of civil Engineering University o f Alberta Edmonton, Alta. T6G 2G7

F.H. Sayles, USA CRREI, P.O. BOX 282 Hanover, N.H. 03755

D. Schebesch The Trow Group Ltd. P.0. Box 430, Station "8" Hamilton, Ont. L8L 7W2

J.F. Schindler Husky Oil NPR Operations Inc. 2525 "c" st. Suite 400 Anchorage, AK 99503

L. Schoen, 18 Park Village, Moscow, ID 83843

E.D. Schunke Dept. of Geography Univ. of Gottingen Goldschmidt Str. 5

Federal Republic of Germany 34 Gottingen,

W.J. Scott, geological^ Survey of Canada, 601 BOOth St. Ottawa, Ont. KIA OE8

D.C. Sego nept. of Civil Engineering University of Alberta Edmonton, Alta. T6G 2G7

P.V. Sellmann,

BOX 282 , USA CRREL

Hanover, N.H. 03755

L. Semenov, USSR Moscow 117321 Tepliy Stan Korpus 2 5 , Kwartira N 406 U.S.S.R.

V.K. Shah Public Works Canada Sir Charles Tupper Bldq Ottawa, Ont. KLA OM2

L.M. Sharma Alberta Dept. of Transport Rm. 214, Transportation Bldg. 9630 - 106 St. Edmonton, Alta. T5K 288

R.R. Sharp, Jr. LOS Alamos Scientific Lab. P.O. B o x 1663, MS 586 LOS Alamos, N.M. 87545

R.W. Sharp, Dept. of National Defence NRHQ Yellowknife

Yellowknife, NWT X1A 2R3 P.O. Services 6666

254

G. Shearer. U.S. Geological Survey, 800 A St., Suite 109, Anchorage, AK 99501

R.G. Sherman, Metcalf & Eddy,

Boston, MA 02114 5 0 Staniford St.

P.P, Shmyglya, USSR, Tumen, Melnikaite St. 2 , 90-a, U.S.S.R.

E. Shusherina, USSR MOSCOW, Leninsky Gori University Geological Faculty U.S.S.R.

R.G. Sisodiya, Gulf Research & Develop, Offshore Technology,

Houston, TX 7 7 0 3 6 P . O . Box 3 6 5 0 6

R.G. Skinner, Dept. of Energy, Mines &

Ottawa, Ont. K I A OE4

L. Skjolingstad, R.M. Hardy & Associates Ltd.

Calgary, Alta. T2P 2w5 310 Bow Valley Sq. XI,

R. Sletten,

P.O. Box 2 8 2 , USA CRREL,

Hanover, N.H. 0 3 7 5 5

C.E. Sloan, U.S. Geological Survey

Anchorage, AK 9 9 5 0 1 218 E. St., Skyline Bldg.

W.A. Slusarchuk, R.M. Hardy h ASSOC. Ltd.

Bow Valley Sq. 11, 310 - 205 gth Ave. S.W.

Calgary, Alta. TZP 2w5

B. Smith, Thurber Consultants Ltd. 1 0 5 0 9 81st Ave. Edmonton, Alta. T6E 1x1

J. Smith, Acres Consulting Services Ltd. 3 0 4 4 9 1 Portage Ave. Winnipeg, Man. R3B 2E4

M . W . Smith, Dept. of Geography,

Ottawa, Ont. K1S 586 Carleton University,

R.C. Smith, Public works Canada Box 4 8 8 , Edmonton, Alta. T5J 2K1

R.E. Smith, Atlantic Richfield Co.

Dallas, TX 7 5 2 2 1 P.O. Box 2 8 1 9 ,

A. Sneguirev, USSR 6 7 7 0 1 0 Yakutsk,

U.S.S.R. Inst. Merzlotovepeniya,

RFSOUKCeS, 580 Booth St.,

C. S . Snyder, Pacific Lighting Gas Develop. C O .

Los Angeles, CA 9 0 0 1 7 7 2 0 W . Eighth St.

J.C. Sobkowicz, 104, 7615 105th St. Edmonton, Alta. T6E 4G9

G. Stablein, Geornorphologisches Lab. Institut fur Physische Geographie

Altenstein S t r 19, Frei>en Universitat

D-1000 Berlin 3 3 , Federal Republic of Germany.

W. Stanek, Dept. of Fisheries & EnviLonment Pacific Forest Research Centre

Victoria, B.C. VBZ 1M5 5 0 6 W. Eurnside Rd.

D. Stenning, Dome petroleum Ltd. P.O. Box 200, Calgary, Alta. T2P 2H8

M . Y . Stoesser, Dow Chemical of Canada Ltd. Modeland Centre P.O. Box 1012, Sarnia, Ont. N7T 7K7

M. Stout, Northern Transportation Co. Ltd. 9 9 4 5 108 St., 14th Floor. Petroleum Plaza, Edmonton, Alta. T5K 2G9

D.W. Strangway Dept. o€ Geology University of Toronto, Toronto, Ont. M5S 1Al

K.L. Strauss, Swan wooster Eng. co. Ltd.

Vancouver, B.C. v3W 1A6 1 5 2 5 Robson St.

H. Tabuchi, Hosei University (Earth Sci.)

Tokyo, Japan 2-17-7 Fujimi, Chiyoda-ku

M . Takano, Civil Eng. Lab., 5 Reg. nopt. Technical Research Center Nippon Kokan K . K . ,

Kawasaki, 2 1 0 , Japan. 1-1 Minami-watarida, Kawasaki-ku

'I. Takashi , Auto-Center Bldg. NO 6 8 Seiken Co. Ltd.

3-Bancho Kawarayamachi, Minami-ku, Osaka, Japan.

H. Tabuchi, Hosei University (Earth Sciences)

Tokyo, Japan 2-17-7 Fujimi, Chiyoda-ku,

Y. Takahashi, Section of Res. & Eng. Production & Eng. Dept. Tokyo Gas Co. Ltd.

Tukyo, Japan. 2-16 Yaesu 1-Chome Chuo-ku

A.M. Tallman,

Rockwell Hanford Operations Richland, WA 9 9 3 5 2

Woodward-Clyde Consultants R.G. Tart Jr.

Anchorage, AK 9 9 5 0 4 6244 Eastwood C t .

G. Taylor, Ohio State University Agronomy Dept. 1885 Neil Ave. Columbus, OH 4 3 2 1 0

R. Tennyson, Fluor Engineers 6 Const. - SGD 3333 Michelson Dr. Irvine, CA 9 2 7 3 0

2 0 2 s / 2 0 0 w

USSR, Kuibylhev 2 . Ter-Mortizosyon

Civil Eng. Inst. Moscow 113114, U . S . S . R .

V.D. Thierman Thierman ti Associates Ltd. 10 Commonwealth Eldg.

Edmonton, Alta. T5K 1c5 9 9 1 2 - 106 St.

W . Tobiasson, USA CRREL

Hanover, N.H. 03755

F . Tordon, Terratech Ltd.

Montr6a1, Que. H4N 1J1 275 Benjamin-Hudon

J.K. Torrance, Geotechnical Science Lab. ncpt. of Geography Carleton University Ottawa, Ont. K1S 586

Dept. of Civil Engineering R. Tse,

University of Alberta

BOX 2 8 2 ,

EdmOntOn, Alta. T6G 2G7

A. Tsourikov, USSR Moskow, 1 1 3 4 5 2 Sympheropol boulevard 21 fl 9 2 . U.S.S.R.

Glaciology, Cryopedology P.L. Tung,

& Desert Research Inst. Lanchow, People's Republic of China

M..J. Turner, Alaska Pipeline O€fice, U.S. Dept. of the Interior 8 0 8 E. Street Anchorage, AK 9 9 5 0 1

E. Unger , Dome Petroleum Ltd. P.O. nox 200, Calgary, Alta. T2P 2HR

R . Unterberger,

Texas A 6 M Ilnivnrfiity Dept. of Geophysics,

College Station, T X

R.O. Van EverdingPn Hydrology Research oiv. Environment Canada Rm. 101, 4616 Valiant Dr. Calgary, Alta. T3A OX9

L.A. Viereck O.S. Forest Service Inst. of Northern Forestry Fairbanks, AK 9 9 7 0 1

T . S . Vinson, Dept. of Civil Eng. Oreqon State [Jniversity Corvallis, OR 97331

V. Volquina,

Yakutsk, USSR 67701.0 Permafrost Inst

U.S.S.R.

S . Vyalov, Moscow 7h385

NIIOSP, U.S.S.R. 2 Institutskayi 6 ,

V..T. Walker,

Louisiana State Ilniv. Dept. of Geography,

Baton Rouge, LA 70803

255

D.S, Walkinshaw Public Works Canada S i r Charles Tupper Bldg.

Ottawa, Ont. K1A OM2 Riverside Dr.

T.A. Walton, National Energy Board 473 Albert St. Ottawa, Ont. KIA OE5

C.K. wang Res. Inst. of the Ministry of Railways, Peking, People's Republic of China

J.L. Wang, Brian Watt Associates Inc. 806 Main Suite 1901 Houston, TX 77002

A.L. Washburn, Quaternary Res. Center university of Washington AK-60 Seattle, WA 98195

T.T. Washburn, Quaternary Res. Center, University of Washington, AX-60 Seattle, WA 98195 U.S.A.

G.F. waters, Construction Eng. Unit, CFB Winnipeg, westwin, Man. R2R OTO

G.A. Watson, 815 w. Bauer ~ d . Napetville, IL 60540

B.D. Watts, 301 7615 105th St. Edmonton, Alta. T6E 4G9

H. Watts, Dow Chemical of Canada Ltd. P.O. Box 1012, Sarnia, Ont. N7T 7K7

W. Wayne,

University of Nebraska Dept, of Geo. Morrill Hal l 412

Lincoln, NE 68588

J. weaver,

University of Alta. Dept. of Civil Eng.

Edmonton, Alta. T6G 2G7

P. Weerdenburg, 306 G.H. Michener Park, Edmonton, Alta. T6H 585

Geotechnical Sc. Lab$. P.J. Williams,

Geography Dept. Catleton University Ottawa, Ont. K1S 586

M.D. Wilson, Dept. of Geology & Geophysics, Boise State University Boise, ID 83725

T.R. Wingrove, Underwood McLellan .& Assoc. (1977) Ltd. 1479 Buffalo Place, Winnipeg, Man. R3T 1L7

M.K. WOO,

McMaster University Dept. of Geography

Hamilton, Ont. L8S 4 ~ 1

Exxon Production Res. Co. D.B. Wood,

HOUStOn, TX 77001 P.O. Box 2189

J . A . wood,

Ottawa, Ont. K1H 5N7 2006 Norway Cres.

C.B. woods,

Edmonton, Alta. 9940 112 St. Apt. 702,

Gulf O i l Canada, 9. Wright,

103 Valhalla Crescent N.W. Calgary, Alta. T3A 127

McGill Subarctic Res. Lab. R.K. Wright,

P.O. Box 790, Schefferville, Quebec.

R. Yacyshyn, 7115 9 4 Ave. Edmonton, Alta.

Y.C. Yen. USA CRREL P.O. ROX 2 8 2 , Hanover, N.H. 93755

F.C. Yip, Foothills Pipelines Ltd. 1600 Bow Valiey Square IT 205 5th AVe. S.W. Calgary, Alta. T2P 2W4

K. Yoneyarna, Res. & Development Inst. Tokyo Gas Co. Ltd.

Minato-Ku, 16-25 Shibaura 1-Chomc,

Tokyo, Japan.

W. Younkin, R.M. Hard & Assoc. Ltd. 910 205 5'h AVe. S.W. Calgary, Alta. T2P 2W5

S. Zabolotnic, USSR Yakutsk 10, Permafrost Inst. U.S.S.R.

S.C. Zoltai, Northern Forest Res. Centre, Canadian Forestry Service, Edmonton, Alta. T6H 3 S S

Documents

03rd International Conference on Permafrost - Preceedings 2 Volumes