anisotropy of compacted clay in shear · anisotropy of compacted clay in shear dissertation...

ANISOTROPY OF COMPACTED CLAY IN SHEAR

DISSERTATION SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS

FOR THE DEGREE OF

Master of Science (Engineering) IN

Building Engineering

BY

Chandra \/\r Gupta

:i.K-,

DEPARTMENT OF CIVIL ENGINEERING Z. H. COLLEGE OF ENGG. & TECH.

ALIGARH MUSLIM UNIVERSITY ALIGARH-INDIA

March, 1981

• » * *

•A * . '• ' ' ^'

X.'.**--,

; D3 7 3I ., J..Kt 'i-

DS731

Certified that the dissertation entitiiKS "AlûtPMY

Qi' CO FACi i S CiM lU CIUAH* which i s being sialMtted tjy

hir* Chandra Vir Gupta t in partial foifiiment of the require*

mento for the awar<3 of degree of Iksaiiter of 'Jclsnee (Bfîneerii^)

in 3uii(3ing iingimering of AXigarh dmlim îlniversity* .Ûgarh

Is record of the ©tudenta, ourn orK carried oat hy hiai iHjder

ray eupervieion and ©aidenee. The reBults embodied in this

dissertation have not tseen suteiitted for the ai ard of arsy

other Degree or DiploEa*

^hi© i^ further to certify that ijr. Chandra Vir Quptat

worked for a ^riod of e i s months • fror, £et cotober* i980 to

3l9t tjarch 1981 for preparation of this »orl:»

( Qr« r.ohd. Haroon ) l^ôfessor of /3oil iêchanics

ALXa 'ill ar^ Foundation r n&ineering Department of Oivil £ngin«erif^

ritedi 3lst liarch-lQSi ^•^^* College of n ;,-;. s I'ech., iateai i i s t i.arcn,X9i5i Ali;,'arh .iuslim University,

Aligarh

In the proparatlon of this dissertation t?» autho?

urieties to express his heart fftit (pratitude to iir* lohd {!aro(m

Professor of 3oiI iechanios and Fouf mtion iingineering*

i^partnent of Civil :>nîi»ering» Aiigarh t' osiie; Universitsr*

Aliî^ for his oonslstent oai ^ ^ cet :û|)ervisiont encoiHpage-

ment and valuable tiis© so freely given throughout the ccmree

of this work.

Thanto are also due to Prof* i ,ti, ATmwtit the present

Hea6» Departr^nt of Civil li;ni:inscring» oxnA rrof. ihaiais 4hiii;adi»

forcier Head* Departi^nt of Civil nnglneering. for providing

al l f&oilitiee &nA for hie encouragojient during the progress

of this «c»rk*

Thsml are also due to iir» ;:iasood llusain* Jr« lab*

Assistant* Joil LahoratcHry for his help in experig^ntal set

up ana to those who helped €lr©otl2r or in<3ireotly in the

present work*

3i9t t aroht i9Bi ( Chmndra Vir Uupta )

In nature th© so l i I® consolidated Bnisotropicall.y

as the horliontsl and imrtioal stresses &Mn^ with th©

&9pth \»Xcm grouud ievei . In order to iRveBtl^te th® aid-

sotropy of c^^apaotefi eluy In shear• the imthtyp resorted to

laboratory! ntudies* fhe so i l wae ecs^paoted in a box a t

optiiaum fviolstura content and samples were taken in different

directions (0°, 3©®t 0® and 90° fv<m horizmiistXi fvcm the

bos. Triaslal te'Jts ^ere cons!i20ted on tnifsa aaiaplos tit

different confining f^^jsures of 1^ k^cs^# 1*5 fcg/ea^ and

8*0 feg/cB • In th is dissertat ion t!\9 s t ress -s t ra ln ohaimc<»

terifstios* peak strengttis, polar Glsp'at;^^ are dlsewHsed and

related to t!ie directions of tlie sj^cipiens tested• I t i s

conoladed that t^haviour of thio ccMapactedir Jol l in shear

le anisotropic and thle ie l»cau8e of the crlentat ian of ao i l

par t ic les paral lel to tiie plan© in whicii ccMpiitlve effcrte is

applied during compaction*

C Q ;j T K,.II f 3

PagB

m&Fmi - III

3.1 frlaxlal ^hear 4|ipanitiffl -j

3.2 L«ma and Defonnatlon wasurliag j , .

3»3 Sols, lisea aiuS i t s p»oj»rti«© 11,

3«« Preparation of soil anfi s aap l i ^ l-v-

3«5 ^©st Frccedor© ,*

^•l i-'-tJ^ss-stPaln oharaoterlstlcsi

^•2 Gheaf Stpcngtij paras^teps

^#3 Polar diatiPais for etiaar strengtli

XI

APFL'iliDIX «> IX

AFKIIIDIX • 111

M J S OF FIOUKO

U^!I' OF SABLCS

34

isif

m

m

In conirentional triaxial eaemr t@st@» the ^mjor

prlriolpai stress is lo vertical dlrdoticist fh« oriental

tlon ©f prlnoipal stress e^stts should not influence tlie

©trenntfi oharacterleties of Isotropio soil©. Hofeever*

most of tfte soils tjotft msn-«sde car m.turmll^ ocotiriwg have

anisotropic ©traoturet and hence there eiist® anisolapopy

of Bh^BT strength in almoet a l l ©oils* fhie r an® usual

isfcoratcrir tests are not able to oorreotljf predict the

l^ftavlour of soils for ostieating the @taMlit^ of Bn mx"

fefiiife;':©nt or feeoring capacity of founc \tionstsince s l l s ta-

bllitgr prot>leE3, assuin® reasonafele rupture siarface oM the

eriantaticn of prinelpal etres© ©jratem along the assussd

failure eurfases change from one point to another as &hmn

in l-'is3 i»l mv& 1»2*

In order to investigate the anieotpopy of oo»i5meted

ela^^ in shear* the aat cap s^aerted to Im'baratoi^ studies*

.aiisarh elasr wae ©oEpaoted at optimum ©oisture content la

a tsox. .:oil spnpies for tr lsxial teste were ttiken at 0®

(horisontal), 30°* 6Q^ wM 90® (vertioal) aireotion froij the

horizontal with the help of thin tube saripler* b i a x i a l tests

were oonduoted on these seiaples at confining pressures of

fe^cm^ ana 2.0 kg/em^» The results of

///^aoAv^

VT (MAJOR PRINCIPAL 1 STRESS)

SLOPE

'HEIGHT OF EMBANKMENT

N A T U R A L S O I L

FIG.n ORIENTATION OF MAJOR PRINCIPAL STRESS ALONG AN ASSUMED FAILURE PLANE IN AN EMBANKMENT.

GROUND /f/WI 7m 7!TO^

D i

B FOOTING

SURFACE TTTO TfyHr-

SURCHARGE=yD

'45-'ty2 II \ " ^ #^5-^/2

• ^ ^ ^ ^ ^

FIG.1.2 ORIENTATION OF MAJOR PRINCIPAL STRESS ALONG AN ASSUMED FAILURE PLANE IN A BEARING CAPACITY PROBLEM.

labopatca^ trlaxial test® show thnt th© undrals^d shear

etrersgth psr«2»t«F8 ©f oo©|sicted el&y of 4llgarf5i varies

mpendin^ en the direction alou^ %hicn tU© clay Is brou^t

to failtiff©# SThe ®ti?tss strain charsct^rintles* peals

©trengthas, poljir aiai^ras'S ar© tllscucsefl ajitS rtlated to tin©

dir@otlon of sôle^n tested*

Vh@ iiivestlâtloa presents th© (5©gr®© of strei^th

?iJ5isotrox^ of B CQsipaotea clsy. I t is expeetsfi thpX 1Kb©

tfîaS will 'd© smm Cov a l l o l a ^ , altliou^.' the .':.agiiit«<t©

of t 'i© strengt!.! dlffereno© .::sy vars" fira:s otm ola^? to amcther*

An attempt hm% tsoon I2*J4© hsr^ to ntxk^.f as to hoer imch le

tri© na piitttc!© of etapongtn difference &>M to orieutatloa of

th© pricîpnl stross ej^stes.

5

In natur® tit« horlKorital and vertical effective

8tre»s®f! a*ian3© %:ith tli© <^-gth aolow <|rouiiKl levtX* The

effective vertical prensur© aJUiO ia not tli© aawe as th«

horlsontal affeotiv© prebsui*© at luiy 6«|)th» I'hua In natur©

also tUB uoil i© consolidated atilsotroplcmlly* ior taa?*-

{fififl© ©FJth ©sfeanEr- int® ttie soil Is GempF.ct«a In Xa ei

«git!i application of vertical pressures# the horlssontal

prec'.fTsa?© almost does not exist. '2huB r aafmd© earth embank-

imntn are aiilsotroplcally ocmpRQtm6* I t has therefcar©

l)88!i reeoiXilsed t f vai*louB r:©searcherQ that the behaviour

of coh©Ji:5sr« sel l In Ehear Is anlBOtrtiplOt

Bishop (19^8) studies th© aideotoopy In shear of

London Clayt vertical mvA Inollmd eauploa w©r© tal^sn for

teiJt In Gheart frosi the naturally occurlng X«ondon Clay» I t

ras otmervsd that the strength of th© inclined samples «s r©

aboat 28','' less tf -an the stre3a§th of th© vertical isauples.

i Mj pton (195^) has also inveetlsated the strength of

Inclined find vertical eartples of natural London t»lay and ob

served that the strength of Inclined eanplee from shallow

depth ¥^re 2S;' less thjin the etrength of vertical sacsples,

fsherea© the strength of Inclined smsples froa greater depth

were only i^ lese than the e t re i^h of vertloul sasiples*

s

ThvsB i t apiâr that at cheater oonaolidatioxi px^nstira

anlsotropy Ifi shear does not play a E;aJor r&ie.

Jaootjsen (1955) etadied the .mlsotropie toh&vloap

of poot»gl30ial Eiarii» oXay of Sweden in &lt«ar« iiat saspl©s

froa th© mturally coctarlng olay at a depth of 3 a baloi^

th© râanSi levcil war© takan at vartical Inclined aw2 feori-

aontal slOi'ô, Th© greatest averas© difference Imtween

any t9ro types of cas-iples ras iftf., Jaoo^sen also ccnioluded

that the swedlah poFt glaoipil earir^ olay wiys almost isotrcpie,

ilenon (i9B0) has recently reported that the U3idrai!^d

Bfeoar etrensth of Uong rii oo-Mao olay vm?ies within &ld« llidLt

denetalins on th© dlreotioa along ^>idch the clay ia lai'ouiiht

to failui^* ior anieotropio coil , the strength will 6©

p ftaaotion of orlentatltm of the epeoir en axis r i ih resj®ot

to th© prinolpal asio direotloji*

Hvor^lev (19^0) 1® probably the f i rs t • investiaâtor

to etudy th© anisotropic Lehavlour of coiisoliCated remoulded

5p©ciE am of O1B;^» II© uaed vienns arid l i t t l e - i e l t clay

and taated trimmed v©ptioal» Xnelined and hoFisontal sarplcs.

He obf orvod thi t th© verticil emcples haim hi^.er strength

thBji th© inellnsd or horiecnf*! sarjples.

I t i2 aJU'-ost octfiblloh©d faot tU^t nstijrally aocariRg

oohoaive coil are anisotropic as re.:^rda the Ghear strength

though anisotropy In shear stren^tti does not play a mfijor

rol© at greater cc!isoll<lation pr©sstjrt®» I t appears fro®

the proo«sa of ocupaotlcn of so i l for trailing ciin1im!L":ent of

roads I (3nL:s arai leveea that thB s e l l of ouch a com true t Ion

wi l l also havo rmlsotroplo behaviour in ehear t)soau30 i t

i9 visu:ali£!e<3 that uurinii the cc^s^ction procesa the so i l

pnrtleloo :30t oriented f:\rallel to the pltm© en v*hicli the

major principal otreas acts during coi^ipaction. .->iiic© the

ccmpaotion io aohievea ^ applying v e r t i c i l co^jpactiw

effort to a layor of s o i l , the so i l part icles j et (oriented

in horinontal dirootion. I t lo therefore postulated that

the ccKsp. cted ooheaive aoil wil l have difi'ercnt shear strength

i f the 3nF::jles nr© ts^en in dlffere:it (directions* I t mas r i t h

thlB in t^n lon that the attar.jrt «ts fid© to stufy the ani»

Gotr-cpy of ecs:nacted so i l in Bh©ar»

a

CHAFT a • III

friexial shear test in oarried out in a tria3U.al

cell whic!i co^nsisto of a perspex cyllnaer fitted t)etirtefi

a tissBB mt^ a top cap* It oon^lsts of loatllrig s»ohif$B oM

X(mjA and deflection tmmnrinz devices. PUotograph of the

triaxi'ii shear test set up is Ehcrnn in Fig«3*|» The

descripticm of the apparattxs is given beIo» i

Triaxial call have thr@© preesura coisnectione throu^

the baseI ceil fluid inlet* pore water out let from botto©

of 6peoit:«n and drainage outlet tttm top of specimen* water^

under pressure is ueually used for buildins up confining

pressure in the cell* In the top cap there is an air release

valve which is kept o^n daring the filling of the cell

with water* A etTLinleee steel piston nrniiir^ throu^ the

centre of the top cap apfli®® the vertical oompreijeive load

(deviator stress) on the speoiisen under test* fhe vertical

load fr&rr the piston acta en a pressure cap resting over

the top of the apeolr^n*

?h© cpeoirsn is enclosed in a rubliar-sesljran© at>out

0*1 or 0*2 £Es In thlcfemss* jopondins won th& drainage

eondltiores of the test* solid ncnpcrous dises or end caps

or poroi^ dlses ore placed on top and botto® end on the

JO

opeoisaen atwS th® rub^r m0m"brf jit 1® sealed on to these

end cans ^ rubt«r rinpt. The effect of the rubber m&m»

Wnrm i s to ellghtly increase the apparent strei^th of

the speclf-^n.

^ e length of the si«cltien is kept fv(m about ô

t© tfe'O BM a telf tlses i t s dlanKJter. -ih® diajsieter of the

epecliaen ie 'oeln^ Itept to be 3*3 cm and the length of the

8|»oli!»n &e 8«5 en*

the vertical load on the speclEwn is applied ^rmflaa-

l ly train a etmined conôlled loading swohine* The load

is iâsured from th© deflection of n callbp^^ted proving

ring reotins on the piston of the cell* the vertical strain

of the s|ieoiEien is meaeared fr<^ the dowjsrard Rovei tent of

the piston as IntSloated tsy another dial ^tis» fixed to the

top cap of triaxie.1 cell*

2t ie usually deeii^^le to tsaintain the cell pressure

constant duping the test . I^pessape la ^ i l t up in i?ater air

reservoir witier byasjotor driven oompreesor or by a tyrepusp.

3.8 LomC.amd Mformtionre^^

5he vertical lead applied on the epecifên i t aeasured

fros the deflection of a calibrated proving r i i ^ resting on

the piston of the ce l l . Immt count of the proving ring io

11

I divifîon • •0001* and the deflection of I dlvisloa on

tne ring develops a Xo&d on the epeoSxian «qmal to Z ib«

?he defoHiiation of the speoieên under the Xtmdlng

%mB sacaswrea tjy dial gauge f IxeS to the tap cap of e

triaxlal cell* Least ooimt of the dlfil fsawge was 1 dlvlalon

• .001"•

3*3 ;M ,..P9f ,J^n^ ,|^9,,fiFppeir^^^

? ?h0 properties of the cohesiiro KOII ussfl In thl©

®taf!y are as folios® i

X) Atterberg 2«liQlt8 •

Uqald Uialt. i | « 28f»

Plaatlo lAaltt*'*p • 21^

rieatlolty Zn<lextl_»â

Frcn the plpstlolty chnrt 8ho?;n in iis«3.2 (I.iil^98»

1959) • the above eoll lo clsisclfled m Oh soil* ihe gstiln

olse al6tribatlcn of the EOII ucea li; also given in ris«3«3»

XI} Sompaotion test •

Utanusra rroctor test mm perforF.ed and the results

are as nn^r i

^%ax» " '*4ixl®uiL Dry Itnsit^? « l»9 t^mP

(-•»£•€.• optliscuBt ^:oi8tlaro Content « %!^

15

U) (9

IU<t

s.

N oeiii

Z 3

T-tr

z "3 ^

3 : \ u N

\

D y « \ UJZ o<t =!9\o2:<i Z ^ 0 3 Z C I <t^ «nC <tuju

111 00 (A

3 0 : w

2 J

O t - -

Z < t j

Q W U .

1 1

z o o

\ I

u

u

\

2 o 0

\ (TO

i'fll|;-\'> • m l - ' A

o o

o

o CO

o

I-

0 2

U OQ.

O-J

3

z o

in in

u

o in

Ok in o»

T

in

o o o o o o tv ^ m <9 n (M

lN33a3d-X30NI AXOUSVld

O UJ m

H GC <t X 3 u > u in <I J 0.

in

6 iZ

18

o z <t in

5

5 U

•0

ID

IT

U

5

z iZ

in

<l o o z 5 ^.

Ui 2

z o

u

in m <I J U

->•

->•

•V

, V, V

• - ^

'

o o

t

E E

w o u> o Z

o

o o o

o in

(J

z I-u. o > C D U z o

OQ

in 5 UJ N In

O

6

o o to o o o O o

J.H9I9M AQ il3NlJ lN3Dii3<i

u

Th9 moistare • fiiry dejisity rolatiuimlilp is ehtrnn

in Flg93»<»«

3«^ ^r9mrmtim of aoil Ana uaaplina

Goll used In this study was sslxed thorooj-i laf «ith

optisram moisture content (G«r;«0») determim^ by standard

lôotor t«9t« After adxlngt th« soil %m ootspacted In

layers in t!ie wooden b«» of sie© 50 « 50 x 25 cm* fh« l>ox

waa filled vith the well oiixed soil in sis Is^^rs and cois*

pating each layer with 800 !>lo«f3 es detercdiwd in proportion

to the etanfiard Frcctor test.

¥rcm the Ixm. the sasples ¥iere taken at an inclina

tion of 0°, JQ^t 60° end 90*^ froia the horleontal with the

help of eac^ler* ?ne Ba.mpleB were ta'ên IToie the cot^paoted

©oil at a distance of t out 10 cm centres to avoid filst«r-

bEuee to tne stîples* All tue saoi^les were tested in about

one mBQks tioe to avoid thixotropio effects in the @oil*

-j.S geet rrocedure

(InconBclidnted • undrained trlajcial shear tests were

carried cut cm renoulded ear pies taken from tlie box. In

this test* tlie 8peoi:.en enclosed in th@ rubber ise&ibrane is

placed between eolid (non«porou3) end caj^» '*»ater un«!er

pressure ii; used for buildl!^«up confining pressure in the

cell* ^ e (iiamcter of tê aiôinen was 3*3 oa aftd the hei^t

15

2 0

15 20 25 MOISTURE CONTENT, V.

30

FJG.3.4 LABORATORY MDISTURE-OENS/TY TEST RESULTS

je

of th« epecimea was 8.5 os« the !»p80ir.8n W«FO t«st«d at

different confining prassures (^3 ) of 1.0 ku/cas^,

I #5 fes^QJa^ ana 2.0 kg/ca^ la^ the lomd waB aispUsd at a

strain rata of O^Q^ sm/miimtt* After applying tlie desired

confining i^^ssure (cell pres ure)» the speoli!»n Is failed

by Increasing axial devlator strain i^ % • ^ 3 )• Hach

test lasted for a perl a! ranslr^ fposi atJOttt 30 to ^5 lalnutes,

17

A series of unconsolidated undrained trlajEiiil. Mh»@r

tests vere conducted on soil speolriins t a ^ n fros a cj^pac^

ted sollt sampled at 0®, 30®, 60® and 90° direetioi;® to the

horisontal* ?he ceil presi;iire ( c(^tfinline presstire* 3 }

adopted ware l.O, 1.5 and 2.0 fej/crs^. The trlsxiiil tests

«ere cajrrled*out s t a strain rate of 0*89 tm/t'Afmt9* omim&ry

of ^ e results of t r las ia l te^^ts are c lven in table A - I ,

A - II* A - III BM A - IV of Appendix • I I I . ^he aversse

of tiro sataples tested at sime oonflning preaeore was tal:en

for ealoaintion*

Geviator stress ( V | • ^ 5 ) varous percentage axial

Btraln for sariples taicon at different directions ( 6®i 30^,

60^ and 90® froo horitontal ) are plotted In Fijj. ^ . i for

ccnfiRin3 precsare of 1.0 kg/ca^t In i'lg» ^.2 for confining

pressure of l»5 ka/ca and in Fig. ^.3 for confinl?^ preD..iire

of 2.0 kg/cB • flie stress - strain curves resulting from

the failur© of horieontjil and Inclir^d sa^iiples stioR pronoun-

ced peaks. I t lo evident ffom tlie8s-ri::fjrey tJiat nnicotropic

effect leads to tlie hi:f:?ier fctllare stress as the inclir^tion

of eas^les increases from ^ e horif»ontal» The failure deflator

stresses versus Inollnation of saisples «lth horizontal i s also

JS

AXIAL STRAIN,%

FIG.^.1 STRESS-STRAIN CURVES FOR. SAMPLES UNDER V3 =1-0 Kg/cm'

TT^

U 8 12 16 AXIAL S T R A I N , %

FIG-/; .2 STRESS-STRAIN CURVES F O R . SAMPLES UNDER V3 =1.5Kg/cm?

2f)

/; 8 12 AXIAL STRAIN,%

FIG-4.3 STRESS-STRAIN CURVES FOR . SAMPLES UNDER 73=20Kg/cm'

21

plotted In rtgt 4.4 for different confining isressures

( ^ 3 ) . Ilhe deviate ::tre8a C "î • ^ 3 J at failure

lnore3S@3 aliiaiit linsfiriy a® t>tt inollnation of the sample

inoremsee from the horisontal* I t can also l;e inferred

t!mt as the cojifinisis iwnaui'e iiioreasres tlie failure stre*

cseo Îiio Insrease for a l l the um-plj^B*

2he oaslmim strain at failure « versus incllimtion

of sanples îth horiEontal are depicted in Fig. 4 .5 . I t

can t)© concluded that the failtare etre3S occore at sjsalier

Btrains c© the Inolunation of sar»ples inoreasee frcaa the

horizontal, fine effect of increase in confining pressore

I0 to further reduce the etrains at failure.

I t Q-n t3@ thus deduced that g^nei:^!!^ stress-strain

characteristics of compacted soils tre dependent on the

direction of opeoii-.en tested, ^his in true for different

confining iirescures also.

Che ohservatloa of maxlaum failure stress In the 90**

( i^rtioal } direction esipS^s and mini&ua at 0* (horizontal)

direction samples taKen ft ou ooiopaoted ccêslve iôil m^ tm

attri^tesS to a certain dei:T8® of orientation of the soil

particles in 'iho dlreotioa periJcmlictalar to tlie cotaiâctive

force.

"fe 8 §•

LK)

in UJ

» -

a.

z X <

6 -

4 -

1.

^3=20 Kg/cnjl.

X

P2

0" 30" 60° 90" iNCLfNATION OF SAMPLES WfTH HORIZONTAL

F/G.4-4 MAXIMUM DEVIATOR STRESS VS INCLINATION OF SAMPLES WITH HORIZONTAL.

0" 30" 60" 90" INCLINATION OF SAMPLES WITH HORIZONTAL

FIG.4-5 MAXIMUM STRAIN AT FAILURE VS INCLINATION OF SAMPLES WITH HORIZONTAL.

23

^•2 P.ftffir ''t|:fr|^^ FfTitiflffyf

OtiXieia^ tlie aevlator stresseo at failurei smjor

wnA minor principal stresses {^i and ^ 3 respectively )

«;ere obtained for vertioml aiid horieontaX caiiple8« and

saisplee ta^n at 30° ana 60** irtm horisontaX. Aversge of

tKO saspliffi tested at tlie 6a»ae oonfinii^ laressur© wis talent

fjie sai pXes *?ere tested st three confining:: ppe::sure8« Tear

the four t pes of saiipXes i*e* verticmXf h&risontal aM

Bm^l99 ta2:en at 30® end 60< frcM the horizontalt Kc Jr

GireXes are pXotted in Fig. ^.S, fe.7t ^«8 and ^.9 respecti

vely* Faiiure envelopes are shourn In these figures* 2he

shear etreng^ p^raiseters •ti* and *0* derived ffron t.ohr

Circles sre giwsn In fable-I. Jhear strength p?xaiaeteitj

of 30** and 60° easiples are alm«Mit sarte. It appears fPGm

the results, that the sajor part of the atrength is derived

6x19 to cohesion for horizontal saapXss* 5?lie faajor chanse

in stref^tht however• id £ue to inoreast in angle of internal

friction '0* tot vertical sacples.

QO

30°

60°

90°

6

6

6

6

•a' (/ig/cmS)

1.40

1.05

i.OD

Oi,90

•^« (ee^pee

16

21

22

26

24

6\-

tfi

Dry Denslry, rdr 177gm/cm^ Molsfupe Contents 16-2%

Foilure Envelope

^•r10Kg/cnrj2

^=1-5Kg/cm^

Vj =20 Kg/cm?

NORMAL STRESS, V- Kg/cm^

FIG.46 MOHR CYCLES FOR VERTICAL SAMPLES

Cr1-40 Kg/cm2

Dry Dcnsily>rd=1-77gm/cfn3 Moisture ConlentslfiVo

T

s1 0 Kg/cnr

rl-SKg/cm^

p 2 0 Kg cm?

NORMAL STRESS, 7" Kg/cm*

FIG.4.7MOHR CIRCLES FOR HORIZONTAL SAMPLES.

25

u Dry Dcnsiry, rd-1-76gm/cm^ Moisfurc Confen^-16-2Vo

Failure Envelope

2 4 6 8 NORMAL STRESS^V- Kg/cm^

FIG. 4f lMOHR CIRCLES FOR 30° (INCLINATION FROM HORIZONTAL) SAMPLES-

E Q\ 6

< UJ

z

i Crl-Oj, Kg/criTl

2 -

j<

Dry Dcnsil"//rd-1-76gm/cm Moisture Conrcnf-16-4Vo

Failure Envelope

NORMAL STRESS, V - Kgfcm^

FIG. 4-9 MOHR CIRCLES FOR 60°(INCLINATION FROM HORIZONTAL) SAMPLES.

2B

flhear strengtli of ai^ so i l l3 given fey i:ohr*cclotiis1)

T f • C • u- tan ^ ( I )

wh®r« T f " ^^®^* atrengt!5 l a Itg/c®

G » Unit cohesion In k^cs?

cTis r^onual strecs a t fctiiurs plu.TJtSt \s/^

0 • Angle of Interasil fr ict ion In dtgree

Equation (1) i s aleo the equation for strength envelope*

The otrength envelope for the horisontalt ver t ica l ana inclined

O'inples of th is pert icalar so i l wil l be as un&mt •

Horieontal sauple •

TfQ « i.«> • ^ r t a n 16® (2)

30® inclined ssusple t

TfjO • 1.05 • ^ tan 2l<> (3)

60® inclined eaiiple •

"^feo • l.OO •'T-tan 22° W

9@o I.e. vertioal ssmple >

'Tf9o • 0,90 •^rt?».n 26° •••••• (5)

^he above strength envelopes are plotted in Fig* 4*10•

It is concluded froa this figure that cohesion predor-iiimtcs

for horlBontfii saisples for 'T-< 2«5 fe^c©^ &M the strength

27

0 1 2 3 ^ 0 5 NORMAL STRESS v; Kg/cm^

FIG. -10 STRENGTH ENVELOPES FOR HORIZONTAL,VERTICAL,30°AND 6Cf INCLINED SAMPLES.

28*

of the hori«ontiii etu^pXe 1@ mot9 than the vertleai saesplo*

ilowevtrt for *^>2«5 ^g/cs^ t!ie intargraitidar strength is

higher thafi cohesion and so strength of vertieal eajrple is

nore than the horisontai smipie* It is also concluded Sttm

this fii^ore that the strength of the horieontal sample for

^T~< 3.5 kg/cm^ ana ''' < 3.0 kg/eia^ is ©ore thun the strensth

of 30** and r>0® inolinecS saEple respectively* Hoirevert the

strength of 30® ana 60° inclined samples are acre thmn the

horisontal f;a^le for '=»"> 3»S feg/cm^ and 'T-> 3 « 0 kg/os?

respectively.

^•3 Polar diagram for ihear :;tgength

Osing ;:ohr^oloumb equations (2)»i3hW and (5)» the

shear strengths for samples of inolination d°t 33®• 69** ai*3

90** froE horisontal were ccKiputed for ^ « 1»0 3£g/cR^, 2.0

feg/cB^, 3»0 kg/ca^ and 4.0 Icg/cia « The saar e is plotted in

FoL«ir dia r^H shewn In Fig. 4.11. A ociaparision tjetireen hori*

sontal shear strsnsl^ ( ^ ) and vertical shear strength ( f^)

is also given in the polar dl^graB. fhe ra.tio in almost one at

'r • 2.0 ks/cffi?, however for '" 8.0 Iq^/cm^ the strength of

horizontal eaiaples ore sore %h:m the vertical samples and for

'3-> 2.0 &g/cni2 the etren:|th of vertical sassples art sore than

the strength of the horisontal samples. The s^ner^l treraS is

observed to b© that as ratio 'y f ^ t g <29creases with the

Increase in noraal etresa • • •

29

<

>

|^=1.24,For\r=10Kg/cm^

2!}=l.06,Forr-=20Kg/cm^

?l3=0-95,For 7-=30Kg/cm^ Tfv ""

|!3=o.88.Forr=40Kg/cm^

30

HORIZONTAL

SHEAR STRENGTH Tf, Kg/cm^

FIG./;.11 TRIAXIAL SHEAR STRENGTH POLAR DIAGRAM FOR DIFFERENT NORMAL STRESSES.

30

i* th9 triaxlaX t«ist results of soil samplts ta]c«n team

ccjupacttd clay of Allgarli» at four different t^lreotlons

(0®» 30 f 60° and 90** Irom horizontal) t shcm that ttio

etress strrtln characteristics of the soil are related

to the direction of the Fpeoli-iSn. ^he devlator stress

at failure of the eanples increases as the direction of

sample Increasee from the horlsontal.

a, The ccffiTacted dm under Investlcmtlon Is finlsotropic tsfith

respect to ghssr ©trt!^h pfiraT?mt-ers 'C* nrv& *0** The

epscl'-en t^r^sa at different Inclinations show different

strrnsth pnr0i!M>t8rs* Thin kin0 of vsrrliitlen In shear

s t r c r^h paranetere of ocmpacted clay fjidlcate that the

ctmvcnticnsl Rsethod of i»ng.ljrsln£, the atability of ©ansade

CBbap^ent or bearing capacity probleia on staMllsed soils

are of^f.tisfaotory and aneoonomlcal.

3» The cohesion prertomirKites for hurl?,ontal aaaplee for ^< &S

l::l/cs^ KM the strength of the horizontal saaples are sore

tnan the stren^sth of the vertloftl aaisplee* lloiiever* for

^r-> g,5 kg/cffi the Intergranat-ir str8n£;th Is h l ^ r

thtn cohsaicm and ao stren,ith of the vertical samples are

more than the otrength of the horiaontal samples.

^« ^he ratio of horiaontal shear strength and vertical shear

31

strenf^h ( Tfj j / T iv ) ^as foa vl to vary wltfe • <3r •

normal stress at failare plant, ^ e increase in ncsKiiil

strecB teiifjs to decr«as© the i^tlo ( Tfh/Tfv )•

S* Ih© in^mstlcatloa presents th@ (fe r®^ of ntrength £nl»

BQtrcrj oi Ali::arh cor'!i)aot9(! olay ciily. I t ir> egpected

tii"t th© tit;n<2 will c® r.iiallar for other c l a ^ elsoi

ft'cyi-: on© oloy to anot!ier.

32

1* A, Senon. Dar Al '/ianflauah (1980), "Onfirali»di .*h«ar

3taren||t^ Anlaotroi^ of Clays*', Intepaatlonal .^yiôslua

cm XmM 'lldeBt Hew^Belhl, /ol*!, pp»l.09*ii2«

2« :)u-noan, J.::» ana 3e®a H. îotton (19^6;, *Anlsotro|^

sjidi rJtF®ss-r®or®ntat.ton in Clay*, ^Joisrnal of th© >;« .«

and Foii!Vtatlor« Divlsjlon, AsGr„ Voi.92,2lo.j«I;..5 Froc.

i-aptr 4903 pp. 2i»50.

3, >Jccnptoa» ^••u.(i9^)# "wli® r-melreaauro Uosf^Tioi^nts

A ai^ ^t aotjtaciii'iiqut, 2mt. ef Ciir. ^ r \ ^# Isandon

^ . Hansen, ty»ij» araa Gibson, :i»K» (I9 9)»**11n«3raine<! :ii«ar

':trength of Aniootropically Gonsoli<!at«d Gl^ys" G«ote«

chnlquo, I r^t . of Civ, iJn^ps. tontlon, lôl.l, *io.3 pp#

l89-20^«

5. Jacotsen, B, (195S)» * Isotropy of Ola^" C#soteclmique,

Irmt* of Civ, :;o<^?3, LoiitJoii, Vol.S, :*o,i, pp. 23-28.

6. 2»o, /..Y. (Juljr 1965)1 • -^tRtJlUty of i/lopes In Anlso*

tropic Joll" tJoamal of tii® ôll neshanlcs KnA fotiRdatlon

Jlvision, iiu€£, Vol.911 1*0. . L.i*, Froo. h'mpsr 4^05 pp.

65»io6.

33

?• Harasen, J.li. (1952) • •• A Oftntral Pla»tiolty theory

for Clay* Oeotechnlqua, Irsat. of Civ» L:i^rs» liOndoii*

Vol.3, rô,4, pp. I5tj*i64.

8# 3is!jop, A«v:« (19^8), * Jon© F-iCtore Involved In the

Oeslp i of a Iarg9 llarth Tins? in the Thames Valley",

Ppoceedln^, 2ns!l International Uonfereiica on ôil

lechonice and Foondatloi^* Hotterdasi, Vol*2*p«l3«

9» Hvorelevt L.J» (t96d}, " l^yslcal Corsponents of the

Jhoar Jtrengtii of saturated Clays", k.l&B Kesearch

Conl rerK»» on tê ^h9W^ strength of Cdlieslve .îolls,

Cenver, Colo*, pi* 169-273,

10, Cl?.^clflcstf.cn aiitfi Idsntifloat!en of .ells ft p General

:'nziTXtrir^ Forprses", Indian :tr?idarfi i 1 '98 • 1959•

I-il, 'let; t^lhl*

http://lcstf.cn

31

APFEIIDZX - It

c~ • Nomial Btr«83 ftt Failor* Flsno* Kg/c»^

^l • fiajop FriR0li»a2. 3trt8s, kg/tm^

^3 - Confining l¥©88ur«, kg/bis^

Ti^-^j . Dtviator Jtrtss, kg/cia^

C . unit Coh.Bion. ks/oo^

^ • Ai^e of Xnttmal Friction in &9gt99

^f • Shear Jtr«ngt!i. kg/cBi

Tfh,Tfo» Kopieontal ihear strength, ke/cs?

^tv Tfofl- *' *'®*^ -hear v)trtngtli» kg/es^

rrf30 • Shear Strength of 30** Znolined (frcac horisontal)

Tfgo • 3hear strength of 60® Xnolined ifrm& horisontal)

sasiplee* kg/ct?

V^ • Dry Densltyt ga/ca^

Tfd ot* laxisjua Dry Density, ^ja/cs^

a»ig«C« optistiB iSoistnre contentt^

W| • Uqiiid U@it, ^

^p • Plastic Liidti^

Ip • Pl^ifiticity Index,

D • Depth of i ounflationi a

B • fcldth of Foun(!iition» m

Qf - Oltioate bearing capacity /

f

t i

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1*1 (îentation of itajor PriiKsipal 2

3tres3 along an asuured fmllur*

plane In uxi embankment •

Flg« 1*2 Orientation of i lajor Prinolpal -

otrtss alor^ an assucied failur«

plane in a Hearing Capaoi^ prol>Iea

i*ig» 3«i Fhotograph of tlio trlEixial Jhsar »

test Get*upt

Fig* 3»^ Plnstioity Chiart Used in ôll

Classification (I~i 11^98-1959)

Pig. 3.3 Grain aise aistriliution Ciirvm of

the Goil.

Fig. 3»^ Laboratory fôisturt-Density test

Heeults.

12

13

IS

Fig. ^.1 iitress-Jtrain Curves fc^ ^miplee under ,„

" 3 • ItO kg/^

Fig. 4.2 3tre©s-wtrain Carvea for .ajaplea under 19

3 " 1»S lig/ca ^ 1 m, * H t . n . / » M 2

41

Pa§t

[m ^•3 U^es8«^)train Curves for . aEples ^

Pig. ^.^ giaxiao^ Devlator -itrass Verstis 22

Inclination of wamplns with horl-

sontal*

Fig. ^mS hlsMimm strain at I-oiluara Vs In-

olination of iaaplea ??lth hrarisontal

Fig. ^.6 EoIiT Circles for Vertical 3aspl«8

Pis. 4.7 i ofiT Circles for Horisontal

3ojsple8

Fig. 4.0 iCohr Circles for 30®(inclined; froa

horlsontal) isunplee.

rig. 4.9 Hoiir uircles for 60^ (Inclined fror.

horleoBtal) Sanples.

Fig. 4.10 -.tren^th envelopea for horlsontal

Verticalt 30^ imd 50° Inclined

Japples.

Pig. 4.11 Trlaxlal -hear -^trenstfi lolar

dlai ram for aifferent fSormal

.stresses.

22

24

24

2S

2S

27

29

AFFEK0IIC • V

xji^'s m '2ABm:^

42

1?&t>l« • A«I 3\ii;3&@r of t r l as la i « h«8r ?«st

H«@ul.t8 for 0^<horlsont&l)

SflSlpI«8»

ûEsaary of frlsxlal wfwiar T»st

Hesulta for 30^ (Xnoilmd fr<m

horleontal.} i:at<,pie8«

fat>l« • A-III StBsaErjf of friesJlal jihesr T#at

BemtXts for 60® C InoUntd flrero

horlsontaX) lâs^les*

Ta&U • A*ZX

3&

. /

3a

Taît • A-IV jusaa^ry of Triaxlal ^hoer ^©st

HestiXts for 90° ( Vertical )

anisotropy of compacted clay in shear · anisotropy of compacted clay in shear dissertation...

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