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BIS 2003

BUR EAU OF INDIAN STANDARDS

This publication is protected under the Ind ian Copyright Act (XIV of 1957) andreproduction in whole or in part by any means except with written permission of the

publisher sh all be deemed to be an infringement of copyright u nder th e said Act.

Ind ian S tandard

METHODS OF TEST FOR SOILS

P AR T XXXI X D I RE C T S H E AR TE S T F O R SOI L SCONT AINING GRAVE L

Se ct io n I La b or a tor y T es t

Soil Engineerin g Sect ion al Comm itt ee, BDC 23

Chairm an R epresenting

PROF DINESH MOHAN Central Building Research Institute (CSIR),

Roorkee

Mem bers

ADDITIONAL CHIEF ENGINEER Public Works Department, Government of Uttar

PradeshSHRI D. C. CHATURVEDI (Alt ernat e )

ADDITIONAL DIRECTOR RESEARCH (RDSO)

Railway Boar d (Minist ry of Ra ilways)

DEPUTY DIRECTOR RESEARCH

(RDSO) (A lt ern ate )

PROF ALAM SINGH University of J odhpur , J odhpurLT-COL AVTAR SINGH En gineer-in-Chiefs Br an ch, Arm y Hea dquar ter s

MAJ R. R. SUDHINDRA (A lt ern ate )

DR A. BANERJEE

SHRI S. G UPTA (A lt ern ate )

Cement ation Co Ltd, Calcut ta

CHIEF E NGINEER (D & R) Ir r iga t ion Depa rtm ent , Govern ment of Pun ja bDIRECTOR (IPRI) (A lternate )

SHRI K. N. DADINA In personal capacity ( P-820, P N ew A lipore,Calcutta 700053 )

SHRI A. G. DASTIDAR In personal capacity ( 5 Hun gerford S treet, 12/ 1Hunger ford Court, Calcu tt a 700017 )

SHRI R. L. DEWAN Irrigation Research Institut e, Kha gaul, Patna

DR G. S. DHILLON Ind ian Geotechn ical Society, New Delhi

SHRI A. H. DIVANJI Asia Foundations and Construction (P) Ltd,

Bombay

SHRI A. N. J ANGLE (Alter nate )

DR SHASHI K. GULHATI Indian Institute of Technology, New Delhi

DR G. V. RAO (A lt ern ate )SHRI V. G. HEGDE Nat ion al Buildings Organization, New Delhi

SHRI S. H. BALCHANDANI (A lt ern ate )

SHRI O. P. MALHOTRA Public Work s Depart men t, Governmen t of Pun jab

SHRI J . S. MARYA Roads Wing, Ministry of Shipping & Transport,

New Delhi

SHRI N. SEN (A lternate )( Continu ed on p age 2 )

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( Cont inued from page 1 )*

M em bers R epresen tin g

SHRI R. S. MELKOTE Centr al Water Comm ission , New DelhiSHRI C. SUDHINDRA (Alt ernate )

SHRI T. K. NATARAJ AN Centr al Road Resea rch Inst itute (CSIR), New DelhiREPRESENTATIVE Hindu sta n Const ru ction Co Ltd, Bomba yRESEARCH OFFICER Building & Roads Research Laboratory,

ChandigarhSHRI K. R. SAXENA Engineering Research Laboratories, Hydera badSECRETARY

DEPUTY SECRETARY (A lternate )Centr al Board of Irr igat ion & P ower, New Delhi

DR SHAMSHER P RAKASH*DR GOPAL RANJ AN (A lt ern ate )

Un iversity of Roorkee, Roork ee

SHRI H . D. SHARMA Irr igat ion Resear ch Institu te, RoorkeeSUPERINTENDING ENGINEER Public Works Department, Government of Tamil

Nadu

EXECUTIVE ENGINEER (Alt ern ate )SHRI B. T. U NWALLA Concret e Associat ion of Ind ia, Bomba ySHRI T. M. MENON (A lt ern ate )

SHRI H . C. VERMA All India Instruments Manufacturers & DealersAssociat ion, Bomb ay

SHRI V. K. VASUDEVAN (Alt ernate )SHRI D. AJ ITHA S IMHA,

Director (Civ En gg)Director Genera l, ISI (Ex-off icio M em ber )

S ecretary

SHRI G. RAMANDepu ty Director (Civ Engg), ISI

Soil Testing P rocedur es an d Equ ipment Subcom mitt ee, BDC 23 : 3

Convener

PRO F ALAM SINGH University of J odhpur, J odhpur

M em bers

SHRI AMAR SINGH Central Building Research Institute (CSIR),Roorkee

LT-COL AVTAR SINGH Engineer-in-Chiefs Bra nch, Army H eadqua rt ersMAJ R. R. SUDHINDRA (Alt ernate )

DEPUTY DIRECTOR RESEARCH(SOI L MECHANICS-I) (RDSO)

Railway Board (Minist ry of Railways)

ASSTT DIRECTOR RESEARCH (SOI LMECHANICS-I) (RDSO) (Alternate )

SHRI R. L. DEWAN Irrigat ion Research Inst itute, Khagaul, Pat naDIRECTOR (I & C) Beas Dam s Project s, Talwara Townsh ip

SHRI K. S. P RE M (Alt ernate )SHRI H . K. GUH A Geologist Syndicate P vt Ltd, Calcut ta

SHRI N. N. BHATTACHARAYA (Alt ernate )DR SHASHI K. GULHATI Indian Institute of Technology, New DelhiSHRI R. K. J AIN Unit ed Technical Consu ltan ts (P) Ltd, New Delhi

DR P. K. DE (A lternate )SHRI O. P. MALHOTRA Building & Road Resear ch La bora tory, Cha ndigar h

RESEARCH OFFICER (BLDG &ROADS) (Alt ern ate )

*He a lso repr esents th e Instit ut ion of En gineer s, India.( Contin ued on page 7 )

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Ind ian S tandard

METHODS OF TE ST FOR SOILS

P AR T XXXI X DI R EC T SH E AR T E ST F O R S OIL SCONTAINING GR AVEL

Se ct ion I L a bo r a to r y Te s t

0. F O R E W O R D

0.1 This Indian Standard (Part XXXIX/Sec 1) was adopted by theIndian Standards Institution on 30 September 1977, after the draftfinalized by the Soil Engineering Sectional Committee had beena ppr oved by t he Civil En gineer ing Division Coun cil.

0.2 With a view to est ablish un iform procedur es for t h e determ ina tionof different characteristics of soils and also for facilitating acomparative study of the results, the Indian Standards Institution isbringing out th is India n St an dar d meth ods of t est for soils (IS : 2720)which is being published in par t s. 38 par ts of this sta nda rd ha ve beenpu blish ed so far . This pa rt [IS : 2720 (Pa rt XXXIX/Sec 1)-1977] dealswith the laboratory determination by direct shear, the shear strengthof soils cont a ining gravel with pa r ticle size more t ha n 4.75 mm on withdisturbed specimen. The test is of two kinds depending upon the state

of samples, namely, laboratory test and in situ test. The in situ test isbein g covered sepa r at ely.

0.3 In t he form ulat ion of t he sta nda rd du e weight age ha s been given t ointernational co-ordination among the standards and practicesprevailing in different countries in addition to relating it to thepr actices in th e field in t his coun t ry.

0.4 This edition 1.2 incorpora tes Amen dm ent No. 1 (Septem ber 1987)and Amendment No. 2 (October 1992). Side bar indicates modificationof th e text as t he resu lt of incorpora tion of th e amen dm ent s.

0.5 In reporting the result-of a test or analysis made in accordancewith this standard, if the final value, observed or calculated, is to ber oun ded off, it sha ll be don e in a ccor da nce with IS : 2-1960*.

1 . SCOP E

1.1 This st an dar d (Pa rt XXXIX/Sec 1) covers t he m eth od for t h elaborat or y deter m ina tion by direct sh ear , of th e shea r st ren gth of soilscont ain ing gra vel (with par ticle size more th an 4.75 mm ).

NOT E It is recomm ended th at th e 300-mm box shall be used for soils cont aininggravel up t o 30 mm size.

*Ru les for r ound ing off num erical values ( revised).

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1.2 The test shall be car ried out at n at ur al moistu re cont ent . In case,t he deposit is likely to get sa tu ra ted, the test sha ll be car ried out in th esat ur at ed condition.

2. AP P ARATUS

2.1 The shear box and its assembly shall conform to requirementsgiven in I S : 11593-1986 Specificat ion for sh ea r box (la rge) for t est ingof soils.

2.2 L oa d i n g D e vi ce The ma jor requirement s of th e loading devicea re t he following :

a) The vert ical str ess on t he sam ple sha ll rema in vert ica l an dconstant during test. The normal load shall be applied uniformlyon th e soil specimen in t he s hea r box without eccent ricity;

b) The shear st ress or stra in sh all be applied in t he same plane asth e dividing plan e of th e two par ts of th e shea r box;

c) In case of a st r ess con tr olled a ppa ra tu s, it sh ould be possible tomaintain a constant rate of stress increase during the testirrespective of the strain rate; proper arrangement shall be pro-vided t o get differen t r at es of st ress in cr ease;

d) In case of stra in cont rolled appar atu s, the str ain r ate shallrema in const an t irr espective of th e str ess. Suita ble ar ra ngement

sh all be pr ovided to provide different str ain r at es; an dc) No vibrations sha ll be tr an smitt ed to t he sam ple dur ing th e test

and there shall not be any loss of shear force due to frictionbetween t he loading fra me a nd th e shear box cont ainer assembly.

2 .3 Weigh t s (I f N ecessa r y ) For providing the norma l load t hr ougha n or ma l loading d evice.

2.4 P r o vin g R i n g of su itable capa city fitt ed wit h dial gaugea ccur a te to 0.002 mm to measu re t he shea r force.

2.5 M ic r o m e t e r D i a l G a u g e s Accu ra te t o 0.01 mm . Two, su itablymount ed to measu re th e horizont al movement and th e ot her t wo suitablymoun ted t o mea su re t he comp r ession or expan sion of th e specimen.

2.6 St op Clock

2.7 B a la n c e of 50 k g capa city sen sitive of 1 kg.

3 . P R E P AR AT I O N OF S P E C I M E N

3.1 Specimen m ay be comp acted in layers t o th e requ ired densit y by asuita ble ha mm er into th e sh ear box after fixing the t wo ha lves of th e

sh ear box togeth er by mea ns of fixing s cr ews.

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4 . P R O C E D U R E

4.1 The sh ear box with t h e soil specimen sh ould be fitt ed int o positiona s shown in Fig. 1. The requ ired norm al load sh all be applied. After

t he required n orm al load is applied, the shear str ain sh all be applied.Before t he a pplicat ion of sh ear str ain, th e upper h alf of th e box shouldbe lift ed up slightly to elimina te fr iction betw een t he pa r ts of th e shea rbox. The sh ear s tr ain sh ould be applied at a const an t r at e of 0.2 mm /min on the upper half of the box till the failure of the specimen. Thefinal shear shall be recorded through the calibrated proving ring. Att he en d of th e test , the specim en sh ould be rem oved from t he box an dt he wat er cont ent at t he shea r zone should be determ ined. The processsh all be repea ted for t h e n ext higher n or ma l load. A m inimu m of 4 setsof rea dings sha ll be tak en.

Figures 1 t o 4 deleted

5 . CALCULATION AND RE P ORT

5.1 Results of tests shall be recorded suitably. A recommendedpr oform a for r ecord ing th e resu lt is given in Append ix A.

5.2 The longitudinal displacement at a particular load shall berecorded from t he shear displacement dial readings.

5.3 The maximum shear force shall be the peak load from load-

displacemen t curve or wher e the t an gent of flat ter por tion of later par tof the cu rve leaves in case t he cur ve does n ot give peak point .

5.4 The maximum shear stress and the corresponding longitudinaldisplacement (shear displacement) and applied normal stress shouldbe recorded for each test and the result should be presented in theform of a graph in which the applied normal stress is plotted asabscissa and the maximum shear stress is plotted as ordinate. Thea ngle which t he result ing straight line m akes with h orizon ta l axis an dt he intercept which t he str aight line m ak es with th e vert ica l axis shall

be reported a s th e angle of sh ear ing resista nce and cohesion in ter ceptrespectively.

NOT E The normal stress versus maximum shear stress relationship may not bestraight line in all cases. In such cases the shear parameter shall be obtained by

drawing a tan gent to th e norm al stress and m aximum shear stress curve at t he pointof norm al st res s expected in t he field.

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A P P E N D I X A

( Clause 5.1 )

P R O F O R M A F O R R E C O R D I N G TE S T R E S U L T S

Plot Shear s t r ess versus shear displacement and find

a) Maximum shear str ess at th e peak of curve, and

b) Corr esponding shear displacement .

P r o fo r m a fo r R e c o r d i n g S u m m a r y of R e s u lt s

Plot Shear s t ress minus norma l stress rela tionsh ip to obtain

a) Cohesion inter cept, and

b) Angle of shea ring resista nce.

P roject. ......................................................... Locat ion of sam ple .........................................

Sample No ......................................................

Ra te of sh ear st r a in .................................... Pr oving rin g No. .............................................

Pr oving r ing cons tan t ....................................

Weight of loadin g fram e .................................

Norma l load a pplied .......................................

S o il S p e c im e n M e a s u r e m e n t s

Dime ns ions ................................................. Area of specimen .............................................

In itia l wet m as s of specimen ...................... Volum e of specimen ........................................Wa ter cont en t .............................................

Bu lk den sit y ................................................

Final wet mass of specimen ........................

Water content at the shear zone.................

P r o fo r m a fo r R e c o r d i n g S h e a r S t a g e

i) Thickness of specimen ......................mm ii) Area of cross-sectionof specimen ...........................................cm2

iii) Ra te of shea ring ......................m m/min iv) Norm al st ress a pplied ...................kg/cm2

DATEAND

TIME

SHEARDISPLACE -

MENT

DIALREADINGS

AVERAGE SHEAR

DISPLACE -MENT

P ROVINGRING

READING

SHEARFORCE

SHEARSTRESS

VERTICALDIAL

READINGS

AVERAGE VERTICALDISPLACE -

MENT

(1) (2) (3) (4) (5) (6) (7) (8)

a b a b

TEST NO. NORMALSTRESS

SHEARSTRESS

AT

FAILURE

SHEARDISPLACEMENT

AT

FAILURE

INITIALWATER

CONTENT

F INALWATER

CONTENT

REMARK

(1) (2) (3) (4) (5) (6) (7)

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