2131-std penetration test

8/6/2019 2131-Std Penetration Test

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Indian StandardIS :2131 - 1981(R4fiied 1997

METHOD FOR STANDARDPENETRATION TEST FOR SOILS

( First Revision )

Third Reprint MARCH 1997

UDC 624.131.381

@ Copurigh 1982BUREAU OF INDIAN STANDARDSMANAK BHAVAN. 9 BAHADUR SHAH ZAFAB MARG

NBWDELHI 1lOOLZ

Gr 3 February 1982


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IS : 2131- 1981( Reaffmed 1997 )Indian StandardMETH O~D FOR STANDARD

PE NE TRATION TEST FOR SOILS( First Revision )-

Soil Engineering and Rock Mechanics Sectional Committee, BDC 23Chairman Representing

DR JAODISH NARAIN Univers ity of Roork ee, Roork ee

ADDITIONAL DIRECTOR RESE ARCH Ministry of Railways( P. E. ) RDSODEP &Y DIRECTOR RESE ARCH( SOIL-MEOE ) RDSO ( Alter na te )SHRI P. D. AQARWAL Public Works Depart ment , Governm ent of Utt arPradesh, LucknowDR B. L. DHAWAN ( AItcrnatcDR ALAX SINQE University of J odhpur , J odhpurCOL AVTAR SIN~H En gine&-in-Chiefs Bra nch, Army Hea dqua rt ersLT-COL V. K. KANITXAR ( Abrnatc )CHIEF ENQINEER ( D&R ) Irrigat ion Depart ment , Governmen t of Pun jab,_ Chan digar hDR G. S. DEILLON ( Alfern& )SHRI M. C. DANDAVATESHRI N. %. DUQ~AL ( Alternate )SERI A. G. DASTIDARDB G. S. DEILLONDIRECTOR, IRISHRI A. H. DIVANJI

SHRI A. N. JANOLE (~Altcmztc)DR GOPAL RAJANDR GOPAL RANJAN

The Concret e Associat ion of India , BombayIn persona l capacity (5 Hungerford Street, 12/I,Hungerford Court, Calcutta 700017 )India n Geotechn ical Society, New DelhiIrrigation Depart ment , Governm ent of Utt arPradesh, RoorkeeAsiaB~~b~at ions an d Const ru ction (P) Ltd,

SERI S. G~~PTAInstitu tion of En gineers ( India ), Calcutt aUn iversity of Roork ee, Roork eeCemin dia Co Ltd, Bombay. \SHRI N. V. DE SOUSA ( Alternate ]SHRI G. S. JAINSHRI VIJAY K. JAIIU Alternate) G. S. J ain & Associat es, Roork ee

( Continuedm gage 2 )

IQ Copvright 1982

BUREAU OF INDIAN STANDARDS I


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IS : zl31- 1981( C o n t i n u e drom page 1 )

Members RepresentingSHRI A. B. J OSHI Centr al Water Commission, New DelhiDEPUTYI;IRECTOR (CSMRS ) ( Alternate )COL M. V. KsYERKAR Ministry of Defence ( R&D )SHRI V. B. GRORPADE Altcraa teSHRI 0. P. MALHOTRA Public Works Department, Chandigarh AdminSHRI D. R. NARAHARI tration, ChandigarhCentr al Building Reztear ch Inst itute ( CSIR

SH RI B. G. RAO ( Alternate )SHRI T. K. N ATRAJ ANDa G. V. RAODR K. K. GUP TA ( Alternate )RESEAROHOFFICER( B&RRL )SH~I K. R. SA~ENASECRETARY

Roorkee -Central Road Research Institute, New DelhiIndia n In stit ut e of Techn ology, New Delhi

Public Work s Depart ment , Governm ent Punjab, ChandigarhEn gineering Research Labora tories, Governm eof Andh ra Pr adesh, Hyderaba dCentr al Boar d of Irr itat ion & Power, New DelhDEPUTYSECBETARYAlternate )SEW N. SIVAQURU Roads Wing (Mmiatry of Shipping aTransport )SHRI D. V. SIKKA (Alternate)SHBI K. S. SRINIVASAN National Buildings Organization, New DelhiSnnr SUNILBERRY ( Altrrnats )SEXIN. SUBRAMANYAM Karnataka Engineering Research Statio

SWPER~NTENDINQE N Q I N E E a ~riahnarajaiagar -( P&D% ) Pu bl;J orh z;rt ment , Governm ent of TamEXECUTIVE NGINE ER SMRD ) ( Alter;: )SHRIG. RAMAN, Director General, IS1 ( Ex-OS& Mmber )Director ( Civ Engg )secretaryS-1 K. M. MATHU RDepu ty Director ( Civ En gg ), BlS

The Site Exploration and Investigation for FoundationSubcommittee, BDC 23 : 2Members

!3xn1V.S. AWARWAL Centr $or~elding Research Inst itute ( CSIRSHRI M. P. J A~N ( Altematr )DR ALAMSINQH University of J odhpu r, J odhpu rDEPUTY DIREOTO~ RES~A~OR Minirtry of Railways(PE), RDSOASEXSTANTIRECTOR ESEAXOH( SOIL MEOH RDSO ( Alternate )DIBEOTOR CSMRS ) Centr al Wat er Commission, New DelhiDEPUTYDI~EOT~~ ( CSMRS ) ( Alternatr )

2( Continusdn pa16 1


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IS1 2131- 1981

Indian StandardMETHOD FOR STANDARD

PE NE TRATION TEST FOR SOlLS( First Revision )0. FOREWORD

0.1 This Indian Standard ( First Revision ) was adopted by the IndianStandards Institution on 24 December 1981, after the draft finalized bythe Soil Engineering and Rock Mechanics Sectional Committee had beenapproved by the Building Division Council.0.2 Standard penetration test conducted by means of the split spoon,specified in this standard, furnishes data about resistance of the soils topenetration which can be used to evaluate standard strength data, suchas .N values (number of blows per 30 cm of penetration using standardsplit spoon) of the soil. Methods of calculation of bearing capacity ofsoils based on N values are covered in IS : 6403-1981*. For obtainingdependable and reproducable samples, a standard procedure is necessaryand this code is intended to furnish necessary guidance to the soil explorerin this regard.0.3 This standard was first published in year 1963 and this revision hasbeen done so as to include a standardized split spoon sampler for which adetailed specification has been formulated separately, besides includingthe details of the correction factors which are necessary in calculation ofbearing capacity.0.4 For the purpose of deciding whether a particular requirement of thisstandard is complied with, the final value, observed or calculated,expressing the result of a test or analysis, shall be rounded off inaccordance with IS : 2-1960t. The number of significant places retainedin the rounded off value should be the same as that of the specified valuein this standard.1. SCOPE1.1 This standard specifies a standard procedure for conducting thestandard penetration test for soils.


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IS : 2131 - 19812 . EQUIPMENT2 .1 Dr i l li ng Equ ipme n t

2.1.1 The equipment used shall provide a clean borehole, 100 to 150 mmin diameter, for insertion of the sampler to ensure that the penetrationtest is performed on undisturbed soil and shall permit driving of the splitspoon sampler to obtain penetration record and the sample in accordancewith the procedure specified in 3.NOTE -The stiffness of the drill rod used for testing influences the N valueobtained by means of the test. A light rod whips under the blows of the hammer.The drill rod shall preferably have a stiffness equal to A-rod (41.3 mm outerdiameter). For depths of exploration more than 10 m, special precautions shall betaken to keep the rod vertical by using centering spacers and/or by using stiff er rodsto minimize the whipping effect. Spacers may be provided at every 10 m, or morefrequently~, if necessary.

2.1.2 Casing or Drilling Mud - It shall be used when drilling in sand, softclay or other soils in which the sides of borehole are likely to cave in. Insandy and other non-cohesive soils, below water table it is oftenpreferable to use drilling mud rather than a casing. If drilling mudalone is not successful, casing may be used along with the drilling mud.2.2 Sp l i t -Spoon Sam ple r - The split spoon sampler shall conform toIS : 9640-1980*.2.3 Drive Weight Assembly

2.3.1 The drive weight assembly shall consist of a driving head and a63-5 kg weight with 75 cm free fall. It shall be ensured that the energyof the falling weight is not reduced by friction between the drive weightand the guides or between rope and winch drum.

2.3.2 The rods to which the sampler is attached for driving should bestraight, tightly coupled and straight in alignment. For driving thecasing, a hammer heavier than 63.5 kg may be used.2.4 Lift in g Ra i l , Ton gs , Rope , Scre w jack e tc~3. PR OCEDURE3 .1 Dr iv ing th e C as ing - Where casing is used, it shall not be drivenbelow the level at which the test is made or soil sample is taken. In thecase of cohesionless soils which cannot stand without casing, theadvancement of the casing pipe should be such that it does not disturb thesoil to be tested or sampled; the casing shall preferably be advanced by

*Specification for split spoon sampler.4


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IS :2131- 1981slowly turning the casing rather than by driving, as the vibration causedby driving may alter the density of such deposits immediately below thebottom of the borehole.3.2 Cleaning the Borehole

3.2.1 In case wash boring is adopted for cleaning the borehole,side-discharge bits are permissible, but in no case shall a bottom-dischargebit be permitted. The process of jotting through an open tube sampler,and then testing and sampling when the desired depth is reached shallnot be permitted.

3.2.2 While boring through soils, such as sands that may be disturbedby the flow of water into the drill hole, no water shall be added to theborehole while boring above the water table. While boring below watertable, the water in the borehole shall be maintained at least I.5 m abovethe level of the water table. Bentonite slurry of appropriate consistency-may be required to help the water level to be maintained above thewater table. The raised level of the water in the borehole should bemaintained even if casing is used to stabilize the borehole.3.2.2.1 While boring through sand using casing to stabilize the sidesof the borehole, the outer diameter of the shell shall be at least 25 mmsmaller than the inner diameter of the casing. The distance between theend of the casing and the bottom of the borehole should be as close aspossible and in any case not exceed 150 mm, if only water is used tostabilize the borehole; in case bentonite is used, this distance may be upto 300 mm.

3.2.3 The borehole shall be cleaned up to testing or,sampling elevation,using suitable tools, such as augers, that will ensure that there is minimummixing up of the soil from the bottom of the borehole. In cohesive soils,the borehole may be cleaned with bailer with a f-lap valve. This shouldnot be used in sands.3.3 Obtaining the Samples

3.3.1 Tests shall be made at every change in stratum or at intervals ofnot more than l-5 m whichever is less. Tests may be made at lesserintervals if specified or considered necessary. The intervals be increasedto 3 m if in between vane shear test is performed.3.3.2 The sampler shall be lowered to the bottomof the borehole. Thefollowing information shall be noted and recorded:

a) Depth of bottom of borehole below ground level,b) Penetration of the sampler into the soil under the combinedweight of sampler and rods (to be noted from readings of thescale over the drill rod at the top),

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IS : 2131 - 1981c) Water level in the borehole or casing, andd) Depth of bottom of casing below ground level.

3.3.3 The split spoon sampler resting on the bottom of borehole shouldbe allowed to sink under its own weight; then the split spoon samplershall be seated 15 cm with the blows of the hammer falling through75 cm. Thereafter, the split spoon sampler shall be further driven by30 cm or 50 blows (except that driving shall cease before the split spoonsampler is full). The number of blows required to effect each 15 cm ofpenetration shall be recorded. The first 15 cm of drive may beconsidered to be seating drive. The total blows required for the secondand third 15 cm of penetration shall be termed the penetration-resistanceJv; if the split spoon sampler is driven less than 45 cm (total), then thepenetration resistance shall be for the last 30 cm of penetration (if lessthan 30 cm is penetrated, the logs should state the number of blows andthe depth penetrated).3.3.3.1 The entire sampler may sometimes sink under its own weightwhen very soft sub-soil stratum is encountered. Under such conditions,it may not be necessary to give any blow to the split spoon sampler andSPT value should be indicated as zero.

3.3.4 If on lowering the sampler by means of a string of rods it isfound to rest at a level above the bottom of the casing, the penetrationtest and sampling should not be carried out at that stratum.3.4 R e m o v a l o f S a m p l e r a n d L a b e l li n g

3.4.1 The sampler shall be raised to the surface and opened. A typicalsample or samples of soil from the opened split spoon shall be put intojars without ramming. The jars shall have a self-sealing top, or shall besealed with wax to prevent evaporation of the soil moisture. Jars shall beof such a size that they can be filled without deforming the sample.Typical samples shall be cut to such a size as to fill the jars and therebyreduce the water loss to the air in the jars. If packing as specified is notavailable, liner may be used in the sampling spoon. In such a case, theinternal diameter of the sampling spoon should be SO adjusted that thetotal internal diameter after incorporating the liner is 35 mm. Thesample in the liner shall be waxed properly at both the ends to keep upthe natural moisture content during transit.

3.4.2 Labels shall be fixed to the jar or notations shall be written onthe covers ( or .both ) with the following information:a) Origin of sample,


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c) Boring number,d) Sample number,e) Depth of sampling,f ) Penetration record,g) Length of recovery, andh) Date of sampling.

3.4.3 The jars containing samples shall be stored in suitable containersfor shipment. Samples shall not be placed in the sun.3.5 Field Observations

3.5.1 Information with regard to water table, elevations at which thedrilling water was lost or elevations at which water under excess pressurewas encountered shall be recorded.on the field logs. Water levels beforeand after putting the casing, where used, shall be measured. In sands,the level shall be determined as the casing is pulled and then measuredat least 30 min after the casing is pulled; in silts, at least 24 h after thecasing is pulled; in clays, no accurate water level determination is possibleunless pervious seams are present. However, the 24 h level shall berecorded for clays. When drilling x&d is used and the water level isdesired, casing perforated at the lower end shall be lowered into theborehole and the borehole bailed down. Ground water levels shall bedetermined after bailing at time intervals of 30 min and 24 h until alltraces of drilling mud are removed from inside the casing.3.6 Corrections3.6.1 Due to Overburden-The N value ior cohesionless soil shall becorrected for overburden as per Fig. 1 (Jv ).

3.6.2 Due to Dilatan cy - The value obtained in 3.6.1 shall be correctedfor dilatancy if the stratum consists of fine sand and silt below water tablefor values of N greater than 15, as under ( x ):N =15f$(JV-l5)

4. REPORT4.1 Data obtained in borings shall be recorded in the field and shallinclude the following:

a) Date of boring,b) Reference datum,c) Job identification,

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X5:2131-1981d) Boring number,e) Sample number,f) Type ofsampler,g) Drilling method,h) Sample elevation and recovery ratio,j) Limits of stratuin,k) Water table information (see 3.5),

m) Soil identification, including condition of samples,n) Penetration records,p) Casing used, andq) Weather data.

CORRECTION OF N-VALUE INCOHESlONLESS SOIL FOR OVERBURDEN


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IS : 2131- 19814.2 The data obtairlecl shall be prepared in a final form as a soil profileto show the nature and extent of the soil strata over the area underconsideration.


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IS :2131 - 1981( Continuedfrom page 2 )

Members RepresentingDIRECTOR, PWDRI Public Works Departmen t, Govr rnm rnt of Utta rEXECUTIVE ENGINE ER ( DESIGN )V Pradesh,. LucknowCentr al Public Works Depart ment , New Dt,lhiEXECUTIVE ENGINE ER ( SMRD ) Public Works Depart ment , Govern men t of TamilNadu, MadrasEXECUTIVE ENQINEE R (CD) ( Altern at e )SRRI M. D. NAIR Associated Instr ument s Manufacturers ( India 1

PROF T. S. NA~ARAJ ( Alternafe ) Private Ltd, New DelhiSHRI T. K. NATRAJANLT-COL K. M. S. SAHASI Central Road Research Institute, New DelhiEn gineer-in-Chiefs Bran ch, New DelhiSRLEIA. K. CHATURVEDI ( Altetnate )SERr S. K. SHODSHRI P. N. MEHTA ( Alternnte ) Geological Su rvey of In dia, Calcut taSHRI N. SIVAXJ nUSHRI P. K. THOMAS ( Alternate ) Roads Wing, Ministr y of Tran sportSU;~~;~~DINO ENGINE ER (IP), Irr igation Department, Government ofMaharashtra, Bombay

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BUREAU OF INDIAN STANDARDSHeadquartersManak Bhavan, 9 Bahadur Shah Zafar Marg, NEW DELHI 110002Telephones: 323 0131 I 323 3375,323 9402Fax : 91 11 3234062, 91 11 3239399, 91 11 3239382Central Laboratory :Plot No. 20/9, Site IV, Sahibabad Industrial Area, Sahibabad 201010Regional Offices:

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2131-std penetration test

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