GeotechnicalEngineeringAspectsofGeotechnical Engineering ... TransTokyoBayHigyway PP.pdf · Trans-Tokyo Bay Highway Project TATSUOKA FTATSUOKA, F. Tokyo University of Science 1

Geotechnical Engineering Aspects ofGeotechnical Engineering Aspects of Trans-Tokyo Bay Highway Project

TATSUOKA FTATSUOKA, F.Tokyo University of Science

1

Geotechnical Engineering Aspects of Trans-Tokyo Bay Highway Project

■ History and structure of Trans-Tokyo Bay Highway

■ Four difficult design factors

■ Significant design and construction issues related to geotechnical engineeringrelated to geotechnical engineering

- Cement-mixed soil- OthersOthers

■ Concluding remarks2

Concluding remarks

Trans-Tokyo Bay Highway

15.1 km-long toll highway3

g g y

Brief historyMay 1971:The technical investigation t t dstarted.

May 1983:The Japanese GovernmentThe Japanese Government approved the construction.

October 1986:The Trans-Tokyo Bay Highway Corporation was established.

M 1989May 1989:The construction started.

December 1997:December 1997:The construction completed; and the highway was opened to

4public on 18th December.

Trans-Tokyo Bay Highway

5

Ukishima access

Kisarazu man-made island

Kawasaki man-made island

Bridge

6

Structure of TTB Highway

・Ukishima access; ・Two 9.5 km-long shield tunnels; ・Kawasaki man-made island; ・Kisarazu man-made island;Kawasaki man made island; Kisarazu man made island;・Bridge

PLAN

PROFILEPROFILE

7

Ukishima access

The starting point of the shield tunnels

8

of the shield tunnels, towards the center of the Tokyo Bay

Steel caisson:1) to start the shield tunnel construction;1) to start the shield tunnel construction;2) the ventilation tower after competition.

Approach fill, retaining shield tunnels.Approach fill, retaining shield tunnels.

9

Ukishima access

10


・Ukishima access; ・Two 9.5 km-long shield tunnels;・Kawasaki man-made island; ・Kisarazu man-made island;Kawasaki man made island; Kisarazu man made island;・Bridge

PLAN

PROFILEPROFILE

11

Kawasaki man-made island

Cross-section

12Artist’s view of the completed structure

A huge offshore diaphragm wall;- 98 m in int. dia.; & 119 m in height; g

13An artist’s view from underground

A i f di h llA ring space for a diaphragm wall

190 m

14

Kawasaki man-made islandImmediately after

Immediately before the ground excavationImmediately after the end of ground excavation

15

Ground improvement by sand compaction pile technology

16

Ground improvement by sand compaction pile technology

17

Construction of external and internal steel structures after necessary ground improvement work

18

19

20

Filling up the ring space with cement-mixed sand slurry

21

Construction of a diaphragm wall in the cylindrical ring of cement-mixed sand fill and cement mixed in situ soft claycement-mixed in-situ soft clay

22

Filled with mud slurry:

Excavation machine

yWhy the vertical wall can stand without support for a so

23

Excavation machine large depth ?

24

Excavation of the inside ground

25

Excavation of the inside ground

26

Construction of the internal structure inside the diaphragm wall

27


・Ukishima access; ・Two 9.5 km-long shield tunnels;・Kawasaki man-made island; ・Kisarazu man-made island;Kawasaki man made island; Kisarazu man made island;・Bridge

PLAN

PROFILEPROFILE

28

Two 9.5 km-long shield tunnels

29


2 2 2 22 2 2 2

Two tubes; constructed Th thi d i th f tThe third one; in the future.

Eight shield tunnel machines worked simultaneouslyt d th t t l t ti i d

30to reduce the total construction period.

Blind typeBlind type using pressurized mud slurryslurry

The world’s largest diameterThe world s largest diameterat the time of construction

14.14 m

31

32

Development of shield tunnel diameter

33

Blind typeBlind type using pressurized mud slurryslurry

The world’s largest diameter

Pressurized mud slurry

The world s largest diameterat the time of construction

Pressurized mud slurry.Why ? 14.14 m

34

Shield tunnel machine re-assembled to startfrom Kawasaki m-m island

35


36

Secondary inner RC liningy g(inside the RC segments)

RC segments

37



PLAN

PROFILEPROFILE

38

Kisarazu man-made island

Shield t ltunnels

39



PLAN

PROFILEPROFILE

40







Concluding remarks

One of the proposals that were not acceptedp p p

42

Four difficult design factors that controlled the structural form

・A relatively deep sea;

that controlled the structural form

・Heavy shipping routes;

43

44




・Heavy crossing shipping routes;・Poor ground conditions; and・A high seismic activity.

Late Holocene very soft clay

Early Holocene sand and clay

45

46

47




・Heavy crossing shipping routes;・Poor ground conditions; and・A high seismic activity.

Late Holocene very soft clay

Early Holocene sand and clay

48

Very high seismic activityIn Tok o Ba areaIn Tokyo Bay area

19231923The Great Kanto Earthquake

49







Concluding remarks

Significant design and construction issues related to geotechnical engineering 1:

Large scale improvement of existing soft clay deposits

related to geotechnical engineering - 1:

Large-scale improvement of existing soft clay deposits by cement mixing in place,

controlling the strength of cement mixed soft clay; and- controlling the strength of cement-mixed soft clay; and - in total 3.77 million m3.

51

Ground improvement techniques by cement-mixingused in the TTB Highway projectused in the TTB Highway project

Cement-treatment method Mixing proportion Construction site Volume; 1,000 m3

Ordinary DMM Cement: 140 kg/m3

W/C ratio: 100 % Ka asaki m m island 132W/C ratio: 100 % Kawasaki m-m island 132

Low strength-type DMM Cement : 70 kg/m3 Ukishima Access 1,248W/C ratio: 100 % Kisarazu m m isl 289W/C ratio: 100 % Kisarazu m-m isl. 289

Kawasaki m-m isl. 168

Slurry type cement-mixed Sand: 1 177 kg/m3 Ukishima Access 1 028Slurry type cement mixed Sand: 1,177 kg/m Ukishima Access 1,028sand (*: 80 kg/m3 in the Cement: 100 kg/m3* Kisarazu m-m isl. 351original design) Clay : 110 kg/m3 Kawasaki m-m isl. 118

Sea water: 505 kg/m3Sea water: 505 kg/m

Dry mixture type Sand: 1,330 kg/m3 Kisarazu m-m isl. 435cement-mixed sand Cement: 100 kg/m3

52

gAnti-segregationadhesive 110 g/m3

Ukishima access

Very soft clay improved by in-situ cement-mixing,achieving a controlledachieving a controlled strength; i.e.,a) strong enough fora) strong enough for

the stability of the structure; and

53b) weak enough for

smooth tunnelling.

54

Cement mixing in placeof soft clay deposits

55

Haneda airport-restriction to the height of gthe construction plants (50 m)

56

Conventional design for cement-mixed soft clay:

Allowable stress method i th ki tensuring the working stress

evaluated by the elastic theory be smaller than thetheory be smaller than the allowable stress, equal to about 1/6 of unconfinedabout 1/6 of unconfined compressive strength

→ Unduly conservative design for huge masses q – ε1 relations from U & CU TC tests on cement-mixed

g g

clay (aw= 20 %) (Kobayashi & Tatsuoka, 1982).

Significant effects of drained condition anddrained condition and confining pressure (when drained)drained)

→ The in-situ stress-strain behaviour is largely different from the unconfined compression test

→ Need for triaxial tests

q – ε1 relations from U & CU TC tests on cement-mixed clay (aw= 20 %) (Kobayashi & Tatsuoka, 1982).

Following the principleFollowing the principle of effective stress, as ordinary soilsordinary soils

Peak stress envelops fromPeak stress envelops from U and CD & CU TC tests on uncemented clay and cement-mixed clay (aw= 8 %, 10 %, 14 % & 20 %) (T t k & K b hi(Tatsuoka & Kobayashi, 1983).

Significant effects of confining pressure onconfining pressure on the drained peakstrengthstrength

→ Not used in the design gto take into account effects of progressive failure

Normalised drained peak pstrength plotted against σc’ for cement-mixed clay (Kobayashi & Tatsuoka, 1982).

Significant effects of confining pressure onconfining pressure on the drained residual strengthstrength

→ Used in the design as gthe conservative strength

Normalised drained residual strength plotted

i t ’/ f tagainst σc’/qu for cement-mixed clay (aw= 8 %, 10 %, 14 % & 20 %) (Kobayashi14 % & 20 %) (Kobayashi & Tatsuoka, 1982).

Nearly no effects ofNearly no effects of confining pressure on the undrained peakthe undrained peak and residual strength at low consolidation a o co so da opressure

Normalised undrainedNormalised undrained peak and residual strengths plotted against σc’/qu for cement-mixed clay (Kobayashi & Tatsuoka(Kobayashi & Tatsuoka, 1982).

Large-scale yield stress, qy, divided by qu versus effective confining pressure divided by q from CD TC tests onconfining pressure divided by qu from CD TC tests on cement-mixed clay (Kobayashi & Tatsuoka,1982)

qr/qu or q /q / (d i d) fqy/qu qr/qu (drained) for

design under static conditionDesign strength in static condition

ADesign strength in zone A was used in the limit equilibrium

qr/qu (undrained)for seismic

the limit equilibrium stability analysis

design

qy/qu (Y1: drained)Normalised drained and undrained residual strengths & drained yield stress plotted against

’/ (T t k & σc’/qu0 σc’/qu (Tatsuoka & Kobayashi, 1983)

Ukishima access

Very soft clay improved by in-situ cement-mixing,achieving a controlledachieving a controlled strength; i.e.,a) strong enough for thea) strong enough for the

stability of the structure; and

65b) weak enough for

smooth tunnelling.

Controlled shear strength of cement-mixed soft clay

qmax (kgf/cm2) (t= 28 days)wn (%) γt (gf/cm3)

Compressive strength after cement mixingmixing

: qu by unconfined compression testsx : qmax by CU TC tests

Original ground:qu (kg/cm2)= 0.044z – 0.88(z= depth; z= 0 m at TP= 0.0).( p )

(m)

66

Too large scatter in the unconfined compressive strength due to effects of sample disturbance, not reliable:Fi l d i i b d th CU TC t t

qmax (kgf/cm2) (t= 28 days)wn (%) γt (gf/cm3)

Final decision based on the CU TC tests.

Compressive strength after cement mixingmixing

: qu by unconfined compression testsx : qmax by CU TC tests

Original ground:qu (kg/cm2)= 0.044z – 0.88(z= depth; z= 0 m at TP= 0.0).( p )

(m)

67Reliable data ?


Construction of large embankments by using


Construction of large embankments by using - cement-mixed sand slurry with a controlled strength at the ramp sectionsat the ramp sections.

68










69


Ukishima access

Embankment ofcement-mixed sand slurry

ithwith:a) a controlled strength;

andand b) a controlled high density

to resist the buoyant 70

yforce of the tunnels.

Underwater placement of cement-mixed sand slurry

71

72

73

No previous construction experiences

→Placement test in a ship-building dock; and block-sampling from the deposit to obtain specimens forsampling from the deposit to obtain specimens for laboratory stress-strain tests to evaluate the strength and stiffnessand stiffness

74

7526 August 1988 ( several years before the actual construction)

7626 August 1988 ( several years before the actual construction)

Reduction of the strengthby absorbing waterby abso b g ateduring under-waterplacement

77

Reduction of the strength by absorbing waterduring under-water placement, not due to losing the cement conentdu g u de ate p ace e t, ot due to os g t e ce e t co e t

78

Sampling of large samples(30 cm in dia) to evaluate possible large scale effects by possibily siginificant in-h i f h i lhomogeneity of the material placed under water.

It was found after TC testsIt was found after TC tests on these large samples and small samples that it was notsmall samples that it was not the case.

79

80

Triaxial testing system for 30 cm-dia. specimens

81

pat the University of Tokyo.

Triaxial testing system for small specimens

82

for small specimensat the University of Tokyo.

Use of LDT with small and large specimens

8312 cm H x 5 cm D 60 cm H x 30 cm D

Membrane

Pseudo-hinge

Phosphor bronzestrain-gaged strip

LDT Instrument leadwire

TerminalGage leadwireActive e.r.s.g.

B'

Heart of LDT(includes electric resistance strain gages, PB strip

(Front)

Teflon tube protection

D' C

A

No. 2

No. 1

Front face (tension side)

terminals, wiring, sealant)

Scotch tape used to fix wireon the specimen surface

(Front)

C'

A'

B

DNo. 3

p

Instrument Leadwire (Back)

Back face (compression side)

No. 4

LDT; Local deformation transducer (Goto et al 1991)

Membrane Surface

84

LDT; Local deformation transducer (Goto et al., 1991).

Dr. Goto,S.; the inventor of LDT (local deformation transducer)LDT (local deformation transducer)

Institute of Industrial Science,University of Tokyo,y y ,1986

85

Summary of results from CD TC tests on large core samples of slurry type cement-mixed sand (Uchida et al., 1993) - Significant effects of consolidation pressure

Summary of results from CU TC tests on large core samples of slurry type cement-mixed sand (Uchida et al., 1993) - Insignificant effects of consolidation pressure

Essentially no scale effects on the peakeffects on the peak strength !

But large scale effects on the stiffness → Why?

C i f ’ t ll

on the stiffness → Why?

Comparison of q-’externally measured axial strains from CU TC tests using small andCU TC tests using small and large core samples from the same mass of slurry type y ypcement-sand constructed in the full-scale field

d t l t t tunderwater placement test (Tatsuoka et al., 1997).

Essentially no scale effects on the peakeffects on the peak strength !

But large scale effects on the stiffness → Why?

C i f ’ t ll

on the stiffness → Why?

Comparison of q-’externally measured axial strains from CD TC tests using small andCD TC tests using small and large core samples from the same mass of slurry type y ypcement-sand constructed in the full-scale field

d t l t t tunderwater placement test (Tatsuoka et al., 1997).

A typical CU TC test on a large core sample of slurry type cement-mixed sand (Tatsuoka & Shibuya 1991)type cement mixed sand (Tatsuoka & Shibuya, 1991).

A typical CU TC test on a small core sample of slurry type cement-mixed sand (Tatsuoka & Shibuya 1991)type cement mixed sand (Tatsuoka & Shibuya, 1991).

Einitial: the value that had been reported by an geotechnical consultant

b t i i l t t f ll i th ti t th t ti→ by triaxial tests following the common practice at that time→ a significant underestimate (about 1/10) of the true value of

small-strain stiffness to be used in deformation analysis ofsmall-strain stiffness to be used in deformation analysis of the cement-mixed soil in the field

The first case where:

1. LDT was used for a practicalcase; and

2 th l ti d l f2. the elastic modulus from triaxial tests exhibits nearly the same value with thatthe same value with that from the field shear wave velocity.

96

The Young’s modulus valuethat had been obtained by

t h i l lt ta geotechnical consultant:Einitial = 0.3 Gpa(by conventional drained TC(by conventional drained TC tests)

Thi l id blThis value considerablyunderestimates the true elastic modulus:elastic modulus: E0= 3.0 GPa

and also the value at theoperating strain !

Th i i h fThe engineers in charge of the TTB Highway project could become confident with

97

could become confident with the use of this material for this project !

Shear modulus vs shear strain relations from monotonic and cyclic loading triaxial tests on core samples (30 cm in diameter) from test fills of slurry type cement-mixed sand (Tatsuoka & Shibuya, 1991).

Strains in the cement-mixed fill lower than 0.05 % (estimated by FEM earthquake response analysis) →by FEM earthquake response analysis) Nearly linear behaviour at small strainsImportance of elastic modulus &d its accurate measurementsp

99

Evaluation of the stress-strain properties of cement-mixed soil filled in the field

to confirm whether fills of cement-mixed soilto confirm whether fills of cement-mixed soil as considered at the design stage were actually constructedactually constructed

100

Underwater placement work of slurry type cement-i d d Uki hi A d Kimixed sand at Ukishima Access and Kisarazu man-

made island (Uchida et al., 1993).

Vessel conveying materials(capacity: 1 000 2 000 m3)

Vessel having a mixing l t ( d ti it

Vessel having Tremmie piles(capacity: 3,000 ton)(capacity: 1,000 – 2,000 m3) plant (production capacity:

450 m3/hour)

( p y , )

V l d l Lift (m)

TP 0.0 m

Vessel carry mud slurry(capacity: 2,000 m3)

( )

Mound produced on the sea bed

Rotary core tube sampling at th Uki hi A Original shore

14 m

the Ukishima Access;a) to obtain undisturbed

samples; and

Original shore protection works

y

5 m

N2N1samples; andb) to measure shear wave

velocities.Steel caisson

Toky

o Ba

yH

ighw

ay

N2N1

Shield tunnels*

Tran

s H

S1S2

(*) th t i thi(*) the top one in this figure has not been

constructed)

102

Comparison of elastic the Young’s moduli from triaxial compression tests (E0) and those from field shear wave velocities p ( 0)(Ef) in the fill of cement-mixed sand (slurry type), Ukishima Access

E and E are similar !E0 and Ef are similar !

103

Comparison of elastic the Young’s moduli from triaxial compression tests (E0) and those from field shear wave velocities p ( 0)(Ef) in the fill of cement-mixed sand (slurry type), Ukishima Access

E0 and Ef are similar !

104

Completed Kawasaki man-made island

193 mFilling of slurry type Cement-mixed sand

Upper RC slab

189 m98 m

TP 5 mOuter jacket

TP – 6 m

35 m 2.8 m 2.8 m4 m

2.8 m 2.8 m 35 m4 m Filling Outer jacket

Inner wall

TP 5 mTP 0 m TP 0m

46.7

m

Slab

TP – 28 m

SCPDMM

Steel pipe sheet pile

TP – 41.7 mSCP

DMM

Steel pipe sheet pile

74.2

m

m

Bottom RC slabTP – 73 m 6

m

21.

5 m

Bottom RC slab

Continuous diaphragm wall (L= 119 m)

Thickness= 2.8 mThickness= 2.8 m 90 m98 m4 m 4 m

TP - 114 m

Filling up the ring space with cement-mixed sand slurry,Kawasaki man-made island

106

A typical test result on an undisturbed sample of cement-mixed sand (slurry type)of cement mixed sand (slurry type)

3 200

MPa

) LDT

Pa)

stre

ss, q

(M

1.5

External100

tress

, q (k

P

Dev

iato

r

CU TC (σc’= 127 kPa) CU TC (σc’= 127 kPa)Dev

iato

r st

Axial strain ε (%)0 0.5 1.0

0

Axial strain (LDT) ε1 (%)0 0.005 0.01

0D

107

Axial strain, ε1 (%) Axial strain (LDT), ε1 (%)

Initial Young’s modulus, E0, based on locally measured axial strains vs initial Young’s modulus, Einitial, based on externally

d i l t i f CU TC t t f imeasured axial strains from CU TC tests of specimens prepared in the laboratory and core sample from Kawasaki man-made island slurry type cement-mixed sand (Tatsuoka etman-made island, slurry type cement-mixed sand (Tatsuoka et al., 1997).

Confirmation that the external axial strain measurement in TC tests is

l li blutterly unreliable to accurately evaluate the stiffness at small strains ofstiffness at small strains of cement-mixed soil.

Comparison of elastic the Young’s moduli from triaxial gcompression tests (E0) and those from field shear wave

l iti (E ) i th fill fvelocities (Ef) in the fill of cement-mixed sand (slurry type) Kawasaki man-madetype), Kawasaki man-made island

E0 and Ef are similar !

109


Construction of large embankments by using


Construction of large embankments by using - cement-mixed sand slurry with a controlled strength at the ramp sections; andat the ramp sections; and

- dry cement-mixed sand at the flat place of Kisarazu man-made islandKisarazu man made island.

110










111


Underwater placement of dry mixture of cement-mixed sand(Ki d i l d)(Kisarazu man-made island):a lower cost and a low quality

112

Underwater placement of dry mixture of cement-mixed sand (Ki d i l d)(Kisarazu man-made island): a new method to minimize the segregation of material during placingof material during placing

Special double-chute

113

Underwater placement of dry mixture of cement-mixed sand(Ki d i l d)(Kisarazu man-made island)

114

Comparison of elastic the Young’s moduli from triaxial compressionptests (Eo) and those from field shear wave velocities (Ef) at the fill f t i dfill of cement-mixed sand (dry type), Kisarazuman-made islandman-made island

E0 and Ef are similar !115

Summary of elastic Young’s moduli of the cement-treated soils in the TTB Project

E d fi d f t i lEmax defined for strains lessthan 0.001 % from triaxial compression tests using LDTs on undisturbed samples (kgf/cm2)

116Ef from field shear wave velocity Vs (kgf/cm2)

RCTBS+DC

Slurry Dry

Cement-treated soilDMM

RCT=rotary coringDC=direct coringBS=block samplingTS=fixed-piston thin-wall sampling

G values from

BS+DC

RCT Kazusa

Sedimentary soft rock Kobe Sagara

Miura

Uraga-A

RCT rotary coring

Uraga-B

Tokoname

G0 values from CU TC tests 5000

BS+DC

Local axial strain measurements

s)

versus 1000Range for Soft rocks andC t t t d il

Pa)

or s

oftro

cks

Gf from field shear wave

Cement-treated soils(BS+DC) and clays

{2(1

+ν)}

(Man

d 0.

42 fo

field shear wave velocities 100

G0=

E 0/{5

for c

lays

Pleistocene clay site

(1:2)(1:

1)(ν=0

.5

TSBS

Tokyo bay

Osaka bay

OAP

Suginami

11710 100 1000 5000

10

Gf=ρ(Vs)vh2 (MPa)

Summary of E0 versus qpeak relations from triaxial tests, TTB project (Tatsuoka et al., 1997).

The strength and deformation characteristics* of cement-mixed soil could be made similar withouta large difficulty to those of natural sedimentary soft rock.

（* should be measured accurately)

1000010,000

10000

10,0001000

E0/q

peak= 1,000

MPa

)

E0/qpeak= 1,0001,000

MPa

)

1000

Pa)

1,000

MPa

)100

E0/qpeak= 100E o (M

E0/qpeak= 100100

E 0(M

100E0/qpeak= 1,000

E0/qpeak= 100

E 0 (M

E0/qpeak= 1,000 E0/qpeak= 100

100

E 0(M

0.1 1 10 10010

Sedimentary softrocks

q (MPa)

Sedimentary soft rocks10

0.1 1 10 100

0.1 1 10 10010

Cement-mixed soil

p

qpeak (MPa)

Cement-mixed soils

E0/qpeak 100

100.1 1 10 100

qpeak (MPa)qpeak (MPa)

Cement-mixed soil having t ll d t th d peak

qpeak (MPa)119

a controlled strength; made intentionally weak

Strength of cement-mixed soil: between soil and concrete

1,000

Manus clay (TC; Jardine 1985)Artificially produced materials

100Manus clay (TC; Jardine, 1985)London clay (TC; Jardine, 1985)

Sand (monotonic torsional shear, n= 0.5)Sand (monotonic drained TC)

Gravel (monotonic drained TC)S d il ( i d i d TC)

10

Pa)

Sandy silt (monotonic drained TC)

Cement-mixed sand in TTB highway project (core samples from full-scale tests)

dry type

1E 0(G

P slurry type

E0/qpeak= 1,000

0.1

Steel (SS41)Hard rock core

(ultrasonic for E0)Concrete

0.01

ConcreteMudstone (Sagamihara)*

Mudstone (Sagara)*Sand/mudstone (Sagara)**: Sedimentary soft rock

E0/qpeak= 100

1200.01 0.1 1 10 100 1,000qpeak (MPa)

: Sedimentary soft rock







Concluding remarks


Construction of shield tunnels;


;a) Consecutively in very stiff cement-mixed soil and very soft

clay at a very shallow depth

122

Ukishima access

A sudden large change Two tunnelsfrom Ukishimag g

in the cutting torque ofshield machine (tonf-m)

from Ukishima

123

( )

Ring number (one ring= 1.5 m)

Ukishima access

Very soft claywith a very thin overlaying soft clay

A danger of floating up

overlaying soft clay

A danger of floating up of the tunnels by large buoyant force acting to the tunnels,g ,compared to a small surcharge; prevented by placing weight i th t l d f l

124in the tunnels and careful tunnelling work.

Significant design and construction issues related to geotechnical engineering - 3:

Construction of shield tunnels with the world’s largest diameter;

related to geotechnical engineering 3:

g ;a) successively in stiff cement-mixed soil and very soft clay at avery shallow depth; andb) underground connection of shield machines with the help of

ground freezing to shorten the drive of each tunnel.

Locations of tunnel connection

125


126

Underground connection of shield machines with the help of ground freezing

Longitudinal section

Cutting faceCutting face gg

Second arrived First arrived

Freezing pipe

shield tunnel shield tunnel

Frozen zone

Freezing pipe

127

Frozen zone

Significant design and construction issues related to geotechnical engineering - 4:related to geotechnical engineering 4:

A huge offshorediaphragm wall;

98 m in int dia ; &- 98 m in int. dia.; &- 119 m in heightfor Kawasakiman-made island.

An artist’s view128

An artist s viewfrom the beneath

Construction of the internal structure inside the diaphragm wall

129

Construction of the internal structure

130

Deep well system to avoid the ground failure by seepage Drainage wells

Observationwellsthe ground failure by seepage g wells

Diaphragmwall

A-sandy layer

Thin clay layer

layer

B-sandy layer

Thick clay layer C-sandy layer

131

layer

Drainage wellsObservation

wellsg wells

Diaphragmwall

A-sandy layer

Thin clay layer

layer

B-sandy layerA serious seepage accident;

Thick clay layerC-sandy

layer

accident;

Start of unusual ground 132

c c ay ayelayergwater spouting 14th Nov. 1993

Time histories of ground water spouting and water depth inside the diaphragm wall

Amount ofDepth of waterinside theAmount of

spouting ground water(m3 per day)

diaphragm wall(m)

First stage Second stage

Depth ofwater in theIncrease in the

rate of ground

Amount ofspoutingground water

diaphragmwall

rate of groundwater spouting

ground water

Start of unusualspouting of

Start of pouringsea water intothe inside of thespouting of

ground waterthe inside of thediaphragm wall

133Date for a period from 14 November to 4th December 1993

Time histories of ground water spouting and water depth inside the diaphragm wall

Amount ofDepth of waterinside theAmount of

spouting ground water(m3 per day)

diaphragm wall(m)

First stage Second stage

Depth ofwater in theIncrease in the

rate of ground

Amount ofspoutingground water

diaphragmwall

rate of groundwater spouting

ground water

Start of unusualspouting of

Start of pouringsea water intothe inside of thespouting of

ground waterthe inside of thediaphragm wall

134Date for a period from 14 November to 4th December 1993

Sea water poured to reduce the hydraulic gradient in the ground inside and immediately below the the diaphragm wall

135

Restart of constructionRestart of constructionafter a delay of six months

136

137







Concluding remarks

Brief historyMay 1971 (25):The technical investigation started.

May 1983 (37):The Japanese GovernmentThe Japanese Government approved the construction.

October 1986 (40):October 1986 (40):The Trans-Tokyo Bay Highway Corporation was established.

May 1989 (43):The construction started.

December 1997 (51):December 1997 (51):The construction completed; and the highway was opened to

139

and the highway was opened to public on 18th December.

CONCLUDING REMARKS-1

The Trans-Tokyo Bay Highway was constructed;a) in a relatively deep sea;a) in a relatively deep sea;b) crossing heavy shipping routes;c) under poor ground conditions; andc) under poor ground conditions; and d) with a high seismic activity.

Several geotechnical engineering design and construction problems had to be solved for theconstruction problems had to be solved for the success of the project.

140


The ground improvement by four types ofcement-mixing technologies solved a number ofcement-mixing technologies solved a number ofpotential technical problems;

1) in-situ cement mixing of very soft clay;a) conventional type deep mixing method (DMM);a) conventional type deep mixing method (DMM);

andb) low strength-type DMM;b) low strength-type DMM;

and2) embankment using;2) embankment using;a) slurry type cement-mixed sand; andb) dry mixture type cement-mixed sand

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b) dry mixture type cement-mixed sand.


Successful construction of shield tunnels with the world’s largest diameter, govercoming several difficult technical problems, including:ga) successive tunnelling in very stiff cement-mixed

soil and very soft clay;y yb) a very shallow depth in a very soft clay with

a danger of floatation of the tunnels; and gc) underground connection of shield machines with

the help of ground freezing to reduce the shield tunnel drive.

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The construction of an offshore diaphragm wall with an int. dia. of 98 m and a height of 119 m was delayed g ya half year by a serious seepage accident in the groundinside the diaphragm wall.p g

a) The accident would have become a fatal one for the )success of the project if relevant measures were not taken promptly. y

b) The accident might have not taken place if the hydraulic gradient in the ground inside and immediately below the diaphragm wall had been made substantially lower, for example, by making the

143bottom of the diaphragm wall substantially deeper than the actual one.

Thank you very much for your attentions !Thank you very much for your attentions !

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Terima kasih atas perhatian anda !Terima kasih atas perhatian anda !

Home page:145

Home page: http://geotle.t.u-tokyo.ac.jp/index-j.html

REFERENCES・Uchida K Shioi Y Hirukawa T and Tatsuoka F (1993) “TheUchida,K., Shioi,Y., Hirukawa,T. and Tatsuoka,F. (1993), The Trans-Tokyo Bay Highway Project - A huge project currently under construction”, Invited Paper, Proc. of Transportation , p , pFacilities through Difficult Terrain, Balkema, pp.57-87.

・Tatsuoka,F., Uchida,K., Imai,K., Ouchi.T. and Kohata,Y. (1997), “Properties of cement-treated soils in Trans-Tokyo Bay HighwayProperties of cement-treated soils in Trans-Tokyo Bay Highway project”, Ground Improvement, Thomas Telford, Vol.1, No.1, pp.37-58. pp

T t k F (2010) “C t i d il i T T k B・ Tatsuoka, F. (2010): “Cement-mixed soils in Trans-Tokyo Bay Highway project”, Soils and Foundations, Vol.50, No. 6, pp.785-804

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