_method of test for soil

8/3/2019 _method of Test for Soil

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IS : 2720 ( P a r t XXXIX/Se c 2 ) - 1979.Indian Standard

METHODS OF TEST FOR SOILSPART XXXIX DIRECT SHEAR TEST FOR SOILS

CONTAINING GRAVELSection 2 In-Situ Shear Test

( First Reprint NOVEMBER 1988 )

UDC 624.131.377:624.131.212

BUREAU OF INDIAN STANDARDSMANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG

NEW DELHI 110002

( Reaffirmed 1997 )


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IS : 2720 Part XXXIX/Sec 2 ) - 1979

Indian StandardMETHODS OF TEST FOR SOILS

PART XXXIX DIRECT SHEAR TEST FOR SOILSCONTAINING GRAVEL

Section 2 In-Situ Shear Test

Soil Engineering and Rock Mechanics Sectional Committee, BDC 23Chuirman

P R O F DINESH MOHAN

Members

Reprcscn tingC e n E E L t r k E i ld i n g R e s e a r c h I n s t i t u t e ( CSIR ),

ADDITIONAL DIRECTOB RESE ARCH, Railway Board ( Ministr y of Railways )( FE ), RDSODEPUTY DIRECTOR RESEARCH,( FE -I ), RDSO ( Alternate)PROF ALAM SINQH University of J odhpur, J odhpurLT-COL AVTAR f41~o.n Engineer-in-Chiefs Bran ch, Army Headqua rt ersMAJ V. K. KANITKAR ( Alternate )DR A. BANERJEE Cementa tion Co Ltd, Calcutt aSHRI S. GUPTA ( Alternate )DR R. K. BHANDARI Cent;~rl$ding Research Institut e ( CSIR ),CEIEF ENDINE ER ( D&R ) Irr igazon Depart ment , Governm ent of Pun jab,

DIRECTOR ( IPRI ) ( Alternate ) ChandigarhSHRI K. N. DADINA In pers onal capacity ( P-820 New A&ore, Calcutta700053 )SHRI A. G. DASTIDAR In personal capacity ( 5 Hungcrford Street, 1211Hungerford Court,. Calcutta 700017 )DR G. S. DHILLONDIRECTOR ( CShlRS ) Ind ian Geotechn ical Society, New DelhiDEPU TY DIRECTOR ( CSMRS ) Centra l Water Commission, New Delhi( Alternate )SIIRI A. H. DIVANJI Asia Foun dat ions & Constr uction ( P ) Ltd,BombaySHRI A. N. J ANGLE ( Altsrnatc )DR GOPAL RANJ AN Un iversity of Roork ee,. Roork ee; and Institutionof En gineers ( Indr a ), Delhi Cent re

( Continusd on page 2 )@ Copyright 1979

BUREAU OF INDI AN STANDARDSThis publication is protected un der the Indian Coptight Act ( XIV of 1957) an drepr oduction in whole or in part by any mean s except with writt en per mission ofth epublisher shall be deemed to be an mfringement of copyright un der th e said Act.


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IS 3 2720 Part XXXIX/Sec 2 ) - 1979( Continuedfrom pass 1 )

Ivfembsrs Repre.wn tingDR SEASHI K. GULEATI Indian Institu te of Techn ology, New DelhiDRG. V. RAO ( AIternat r )SHRI 0. P. MALEOTRA Public Works Depar tmen t, Govern men t of Pun jab,ChandigarhSxrn ~ T. K. NATAXAJ AN CenbNa$ lReyhf Research Institu te ( CSIR 1,REPEE~~TATIVE IrrigaFion Research Institute, Khagaul, Patn aRESEIIRCH OFFICER Building St Roads Research Laboratory,CbandigarhSlrr cr K. R. SAXENA En gineering Research Laboratories, Hydera badSECICETARY Centr al Board of Irr igation & Power, New DelhiDEP UTY SE CRETORY ( Altcma tc )SHRI M. M. D. SE!CFI Public Works Depart ment , Govern men t of Utt arPradesh. Lcuknow

DR B. L. DHAWAN ( Att ar nctc )SIII%IM.-K. SINoHAL Irrigation Research Institute, RoorkeeSm31 N. SIvAolJ RU Roads Wing (Ministr y of Shipping &Transport )SHRI D. V. SIKKA ( Altmt at c )SHRI K. S. SR~IVASAN Nat iona l Buildings Organization, New DelhiSHRI SUNIL BERRY ( Altcrnats )S~~~~;ENDINO ENGINEER Public Works Depart ment , Govern men t of TamilNadu, Madras EXECUTIVE EN QINEE R( SM&RD ) ( Alt.mats )Snnr B. T. UNWALLA Concrete Associat ion of Ind ia, BombaySHRI T . M. MENON ( Altematc )SERI H. C. VERYA All India Instr umen ts Manu factur ers & DealersAssociation, BombayS-RI V. S. VASU DEVAN ( Alternate )SHRI D. AJITH A SIMHA, Director Genera l, BIS ( Ex-oficio Member )

Director ( Civ Engg )Secretary

SHRI K. M. MATHWDepu ty Director ( Civ En gg ), BIS

Soil Testing Procedures and Equipment Subcommittee, BDC 23 : 3Convmef

PROB ALAM SINoHMembersSxiRI AYAR SIN oH

University of J odhpur , J odhpurCentr aJ ora~~~lding Research Institu te ( CSIR ),

SHRI N. M. PATEL ( Altsrnatc )LT-COL AVTAR SINUE En gineer-in-Chiefs Bran ch, Army Headqu ar tersMAJ V. K. KANITKAR ( Alternate )( Continurd on page 12 )

2


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IS : 2720 ( P a r t XXXIX/Se c 2 ) - 1979

Indian StandardMETHODS OF TEST FOR SOILS

PART XXXIX DIRECT SHEAR TEST FOR SOILSCONTAINING GRAVELSeCtion 2 In-Situ Shear Test

0. FOREWORD0.1 This Indian Standard ( Part XXXIX/Sec 2 ) was adopted by theIndian Standards Institution on 11 July 1979, after the draft finalized bythe Soil Engineering and Rock Mechanics Sectional Committee had beenapproved by the Civil Engineering Division Council.0.2 With a view to establishing uniform procedures for the determina-tion of different characteristics of soils and also for facilitating acomparative study of the results, the Indian Standards Institution isbringing out this Indian Standard on methods of test for soils ( IS : 2720 )which is being published in parts. Fortyone parts of this standard have beenpublished so far. This part covers direct shear test. The test is of twokinds depending upon the state of samples, namely, laboratory test andin-situ test. The laboratory test is covered in Section 1 of this part. Thispart [ IS : 2720 ( Part XxX1X/S ec 2 )-1979 ] deals with in-situ deter-mination by direct shear, the shear strength of soils containing gravel andcobblestone.0.3 In the formulation of this standard due weightage has been given tointernational co-ordination among the standards and practices prevailingin different countries in addition to relating it to the practices in the fieldin this country.0.4 In reporting the result of a test or analysis made in accordance withthis standard, if the final value, observed or calculated, is to be roundedoff, it shall be done in accordance with IS : 2-1960*.

1. SCOPE1.1 This standard ( Part XXXIX/Sec 2 ) covers the method for thedetermination by direct shear, the in-situ shear strength of soils containinggravels and cobblestone.

*Rules for rounding off numerical values ( revised ).3


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IS : 2720 ( P a r t XXXIX/Se c 2 ) - 19792. APPARATUS2 .1 Sh ea r Bo x - The side of the shear box shall be not less than 10times. the maximum expected particle size and the thickness of the samplesnot less than three times the maximum particle size. For convenience inhandling the box could be of built-up sections from plates. The foursides of the box could be connected through bolts and nuts designedproperly to form the box. Figure 1 shows the suggested size with1 500 X 1 500 mm sample size.2.2 To p Lo ad i n g P l a t e ( s ee F i g . 2 ) - A rigid steel plate fitting in theshear box suitably designed to distribute the load uniformly over thesample normal to the shear plane.2.3 H y d r a u li c J a c k - Suitable remote control hydraulic jack of adequatecapacity for applying shear force.2.4 Ro l led S t ee l J o i s t an d Wo o d en S leep e r s - Adequate number ofrolled steel joist and wooden sleepers and sand bags for making aplatform and providing adequate kentledge for applying normal load onthe sample.2.5 Ro l l e r s - Suitable size of rollers equal to the width of plates formingthe shear box frame to be placed in between the side of the box and a bedplate on either side of the box.2.6 D a t u m B a r s - Suitable section of steel bars to be hinged for twopegs fixed at a distance equal to the side of the box driven to a depth ofminimum 500 mm on either side of the box.2.7 S p r i n g B a la n c e - Spring balance of 10 kg capacity of sensitivity10 kg to weigh the sand bags.

3 . P REP ARATION OF SPE CIMEN3.1 A steel box made out of mild steel plates of adequate thickness,provided with a cutting edge with the required internal dimension maybe used for trimming the sample. This hollow box be pressed into thedeposit under a load applied by hydraulic jack ( see Fig. 3 ). The soilaround the box be excavated, simultaneously with the penetration of thebox to facilitate its easy sinking. Care shall be taken to ensure that thebox shall sink in vertical position.

3.1.1 Alternatively, during excavation two blocks, of the required sizebe left undisturbed at the desired position. After the excavation iscompleted the assembled boxes shall be put on the top of the block andsoil below the plate shall be excavated gradually till the boxes reach therequired position.4


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IS : 2720 ( P a r t xxxI x/s t !c 2)-1979

- -.--1 LOADING FACE

NOTE - All members fabricated out of 10 mm thick plates.All dimensions in millimctres.

FIG. 1 SHEAR Box 1 500 x 1 500 mm SIZE5


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IS t 2720 Part XXXIX/Sec 2 ) - 1979

SECTION XXNOTE-All members fabricated out of 10 mm thick plates.

All dimensions in millimetres.FIG. 2 TOP LOADING PLATE

3.2 Two rolled steel joists form the bed plates. A train of rollers shall beput in between the sides of the box and the bed plates on either side ofthe box. Gravels projecting above box frames shall be removed and thegap shall be filled up with medium to fine sand to give level surface forbetter seating of the top plate.3.3 The loading cap befitting the internal dimension of the box made ofsteel plates of adequate thickness be placed on the soil.

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IS : 2720 Part XXXIX/Sec 2) - 1979

FIG. 3 ARR ANGEMENT F OR OBTAINING SPE CIMENF OR In-Situ SHEAR TEST3.4 The test should be carried out at moisture content as close to fieldcondition as possible.

NOTE In case of s o i ls co n t a i n i n g f in e s m o r e t h a n 12 percent, the test may beconducted in soaked state t o simulate for worst field conditions; the soaking periodmay extend up to 4 days depending upon type of soils.4. APPLICATION OF NORMAL LOAD4.1 The normal load on the sample shall be applied with the help of aplatform made of rolled steel joist and wooden sleepers and loaded withsand bags ( see Fig. 4 ).5. TEST PROCEDURE5.1 The shear force shall be applied through a remote control hydraulicjack and proving ring arrangement taking reaction from the adjacent box(see Fig.4).

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PROPOSEDFOUNOATlON LE-s-e

PLANE OF SHEAR \SHEAR Box

FIG.4 TESTSET UP FOR LARGE SIZE In-Situ SHEAR IMT


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IS : 2720 Part XXXIX/Sec 2 ) - 19795.2 Two tests at different normal pressures shall be carried out at onelocation. After the block with lesser normal pressure failed, the spacebetween the failed block and the side of the pit shall be blocked byboulders and also by struting. The normal load on failed block shallbe increased, and then the test on the other block shall be completed bytaking reaction of shear force from the failed block.5.3 The jack shall be so fitted so that the application of the lateral loadoccurs as far as possible near to the plane of shear.5.4 The test shall be conducted by giving an equal increment of shearload under the normal load, each increment of shear load shall be main-tained constant till the equilibrium conditions are reached, the readingsshall be recorded with the help of suitably mounted dial gauges. Thenext increment of shear load shall then be applied and the processcontinued till the failure of the specimen occurs. The normal loadsapplied shall be more than the existing over-burden and cover theanticipated loading range in the area. The range of normal load shouldrepresent the site loading conditions as far as possible. Two moretests at different normal loads shall be carried out at ad.jacent location, tomake four tests, a minimum number required necessary for interpretation.

6. CALCULATION AND REPORT6.1 Results of test shall be recorded suitably. A recommended pro formafor recording the results is given in Appendix A.6.2 The horizontal displacement at a particular load shall be recordedfrom shear displacement dial readings.6.3 The maximum shear force shall be peak load from load displacementcurve or where the tangent of flater portion of the later part of the curveleaves in case the curve does not give peak point.6.4 The maximum shear stress and the corresponding horizontal displace-ment and applied normal stress shall be recorded for each test and theresult be presented in the form of a graph in which the applied normalstress is plotted as abscissa and shear stress as ordinate. The angle whichthe resulting straight line makes with the horizontal axis and the interceptwhich the straight line makes with the vertical axis shall be reported asthe angle of shearing resistance and cohesion respectively.

NOTE - The normal stress versus maximum shear stress relationship may not bestraight line in all cases. In such cases the shear parameter shall be obtained bydrawing tangent to the normal stress andmaximum shear stress curve at the point ofnormal stress expected in the field.

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IS : 2 7 2 0 ( Part XXXIX/Sec 2 ) - 1 9 7 9APPENDIX A

( Clause 6.1 )I PRO FORMA FOR RECORDING I&Sf lU TEST RESULTS

Project . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Location of sample . . . . . . . . . . . . . . . . . . . . .Rate of load Specimen No. . . . . . . . . . . . . . . . . . . . . . . . . . .increment . . . . . . . . . . . . . . . . . . . . . . . . . I . . . Depth of test . . . . . . . . . . . . . . . . . . . . . . . . . . .

Proving ring No. . . . . . . . . . . . . . . . . . . . . . . .Providing ring constant . . . . . . . . . . . . . . .Normal load applied . . . .., . . . . . . . . . . . .

SOIL SPECIMEN MEASUREMENTDimensions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Maximum size of (particle . . . . . . . . . . . .Initial water content . . . . . . . . . . . . . . . . . . Area of specimen . . . , . . . . . . . . . . . . . . . . . . .Final water content . . . . . . . . . . . . . . . . . Height of specimen . . . . . . . . . . . . . . . . . . . . .

Volume of specimen ...................Unit weight of soil .....................

II PRO FORMA FOR RECORDING SHEARINGi) Thickness of sample . . . . . . . . . . . . . . . . . . . . . . . . mm

ii) Area of cross section of sample . . . ,.. . . . . ems

STAGE

iii) Rate of shearing ,............... 4. . . . . . . . . . mm/miniv) Normal stress applied . . . . . . . . , . . . . . . . . . . . . . kg/cm2

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IS : 2720 ( Pa r t xxx n c/sec 2 ) - 1979Date& Shear Dis- Shear Dis- Average Proving Shear Shear Vertical VerticalTime placement placement ShearDial Read- Dis- Ringing Reading

Force Stress Reading Displace-mentplacement+*

Dru DN DM DM Dp Dp ClAverageVerticalDisplace-ment

Plot - Shear stress versus shear displacement and find:a) maximum shear stress at the peak of curve, andb) corresponding shear displacement.

III PRO FORMA FOR RECORDING SUMMARY OF RESULTSTestNo. Normal Proving S hear StressStress Ring at FailureConstant

Shear Initial Final Water RemarksDisplace- Water Contentment at ContentFailure

Plot - Shear stress-normal stress relationship to obtain:a) cohesion intercept, andb) angle of shearing resistance.

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IS : 2720 Part XXXIX/Sec 2 ) - 1979( Continuedfrom page 2 )

Members RepresentingDEPUTY DIRECTOR REBEARCHI FE-II ) t RDSO ) Ministry of RailwaysDEPU% DIRE&OR RESEAXCH( SM-III ) ( RDSO ) ( Alternate 1DIRECTOR CSMRS )DEPUTY DIRECTOR( CSMRS ) Centr al Water Commission, New Delhi( Aknatc )DR GOPAL RANJANSam I-I. K. GUHASARI N. N. BHATTACHARAYA( Alternate )SHXUSHASRI K. GULHATISBXI 0. P. MALHOTRA Indian Institut e of Techn ology, New DelhiPublic Works Depart ment , Governm ent of Pu njab,Chandigarh)ESEARCH OFFICER ( AlterturtcSam P. JALOANNATHA AO Centr al Road Research Institu te ( CSIR ),New DelhiREPRESENTATIVE Irrigation Research Institute, Khagaul, PatnaSHRI M. M. D. SETH Public Works Depart ment , Govern men t of Utta rPradesh, LuchnowDR B. L. DHAWAN t Alternate )

Un iversity of Roork ee, Roork eeGeologists Syndicat e Pvt Ltd, Calcutt a

SHRIH. C.VERMA ~ Associated Instr umen ts Manu factur ers ( I ) PvtLtd. New DelhiROF T. S. NAoaRAJ ( Alternate )

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_method of test for soil

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