7o

This study shows that the testing technique und choice of failure criteria are of pri~a~y impor- tance for the definition of the internal friction angle of silts. It also shows that the time dependence of the undrained she~r strength of silty soils increases with increasing clay content. The deformation to failure of :~ silt with a low clay content is m unique function of the friction angle independently of the stress level and void ratlo~ /s indicated by direct shear tests, the urdrelned strength increases with increasing clay content. The drained strer~Thh , on the other h'~nd, decrease~ with increasing clay content. The study olso shows that consolidation of ~ silt creates three zones in a stress diagram with different stress-straln properties. Auth.

833057 EW/~UATION OF THREE-DI!~Y:ION%L ~F..:2 TE~TING Ergun, M U Proc 10th International Conference on Soll

Mechanics and Foundation Engineering, Stockholm, 15-19 June 1981, V!, P593-596. Publ Rotterdam: :-.. ,,\. Balkema, 1981

Reviews designs a~ail~ble for tri.~xicl testing apparatuses and testing procedures far testing cuboid samples of coheslonless soils in the generalised stress field. Results obtained from triaxlal tests in this and previous studies ~re examined. It is concluded that the w~riation of friction angle with increasing intermediate principal stress is Ir~rtly due to the different designs and partly due to the different ,methods of stress application. The most probable vari- ation of friction angle with increasing inter- mediate stress is selected and a failure crite- rion proposed.

833058 SHEAR S~RE~3TH OF P~/~TILLLY ~ATURATE/D :~OILF Gulhati, S K; SatiJa, B Proc lOth Interr~tlonal Conference on Soil

Mechanics and Foundation Engineering, Stockholm, 15-19 June 1981, VI, P609-612. Publ Rotterdam: ~. A. Balkem:::, 1961

Using results of tri~xial shear tests and data available from the literature, an equation is presented for the strength of perti~lly satu- rated soll in terms of 3 measurable stresses: the total stress, the pore w~ter pressure and the p~re air press~me.

833059 EFFECTS OF PARTICLE f!ZE DI~IBUTION ON THE BEEAVIOUR OF TILL

Orr, T L L; Hartford, D; Kirwan, R W Proc iOth International Conference on ~oil

Mechanics and Foundation Engineering, Stockholm, 15-i 9 June 1981, Vl, ~Uql!-715. l~Ibl Rotterdam: ~. A. Balkema, 1981

The results of u/rlralned tri~xluul tests, Atter- berg limits tests and oedometer tests on ss~mples of glacial till with v~rlng proportions of coarse and fine material ~e presented. It is concluded that the shear strength par~aneters of the till measured in the laboratory are governed by several factors including the par- ticle size distribution, the moisture content and dry density of the s:~mple.

833060 RELATION OF TRI~C<L,~/_ A}~ FI~NE ~UT~J, IN :?TREN3THs R a ~ , T; Tokhl, V K Proc 10e~h Interrmtional Conference on ~oll

Mechanics and Founde.tion Engineering, Stockholm, 15-19 June !981, v!, P755-758. Publ Rotterdam: /. ~:. B.d_ke.~.~, !98]

833061

833062

Theoretic:~l expressions i~re d~ived to ~edict the plane strnin strength from the results of ic,:isyTr~netric trl.xi~l compression te~t,~, "ep ' - r.~te equations 're showr~ to be viiid for dense s:~nds tested under fully dr-lned condition~ which show significt:nt di]Ii:tion :t f: :lure nd for loose sunds which s h o w orZy slight dll' tlon or contractio~ ":t f~ilure. The e~u:tion~ <re- sented ere ~!id when ~oils re te,~te:1 urder fully drnined conditions n e:,,pres~io~: i~ ~e- sented to predict ~ri' tion of f! ne ~r in strength with relative density.

DET~!IN.-:TION OF DR.:~:~ "h~ R T!bvUG~{ OF CO][F <T,~ 70Z!,?

-chef f let, H; Ullrieh, 1 Proc lOth Interrmt~or~! Cor~erence on oll

~4echr, nlcs und ~our~"~tlon Engineerir~, .~tockholm, 15-19 June 198], VI, P7~5-77~ • Publ Rotterd:c: .... B,~ikem:, !9:'~

The torsion ring she~m test is used to deter- m~[ne the drained pe~k stre~ngth .rod residt~:l strength of cohesive soils, but re]uires long test times. It is sh~n from ring she'r tests carrie4_ out on :~ preconsolid:ted cl,~y of high plasticity thct the test time c:~n be reduced by the :~p;licatlon of different velocities in the initial-; pe~k- ' r id pos*.-pe:~k-r, nge.

RESIDU~q~ f~ENG~ ~ }R'ORLTW P'R ~T~R~ OT CLAYS

Tinoco, F H Proc lOth Interm~tio~l Com~erence on ~oll Mechsnlcs "~nd Foundation Engineering, Stockhoh~, ]5-19 June 1981, V], P60! -8 ]0 . Publ Rotterdam: / . Z. ~Ikem~, !gd~

The Hvorslev effective 'ngle of interml friction was redefined as the reside:] effective nngle of intern~l frletlon, allowing the determin'~,tlon of Hvorslev per~eters from tri~xi 1 shear, direct sheem -~nd ring shenr tests on undisturbed s~ples of stiff clays. The exper!ment~l d.~t.~ was obtained from -~ comprehensive set of vub- lished she~m tests on blue London Cl,y. The re~u/ts of the Investig:~tion showed th-t the peak effective cohesion m:y be expressed ms power lsw of the effective norm:,l stress :t failure on the f~lure plane for the blue cl.y and the reduction of effective cohesion from peak to residu:~l strength w:~s expressed ~s ': power law of she~r displacements. The proposed formulutlon for the shec:r strength of the b]ue London Cluy was : pilled to the c~ icul:~tlon of be'~rlng Cul~city of ~ circul~-m plate ~nd com- pared to the results from pLte lo~ding tests. The modlfic:~tlon of the Hvorslev p'~r'meters makes them up?lic-~ble to slopes nd found, tion st~billty problems.

833O63

Deformation characteristics

See also: 833049

SPECD~N SIZE EFFFCT IN ~l?q~ ~:P TE~ VUcetic, ).I; l.acasse, f J Geotech Engng Div ?TCE, V]O5, ~'~TI2, Dec 1982,

P1567-1585

This paper ~resents the results of ': l'~borqtory investigation of the influences of height to diameter rstio .~nd membr,,ne stiffnc~s on the beh~vlour of cl,~y in the NGI ~imple she:~r .~pp:.- r'~tus. ~ne study incl,.~led 21 str. in-controlled, constant volume, monotonic lo ding (st.,tic)