IS 4968-2 (1976): Method for subsurface sounding for soils ...

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IS 4968-2 (1976): Method for subsurface sounding for soils,Part 2: Dynamic method using cone and bentonite slurry [CED43: Soil and Foundation Engineering]

Gr 3

IS : 4968 ( Part II ) - 1976 ( Reaffirmed 2007 )

Indian StandardMETHOD FOR

SUBSURFACE SOUNDING FOR SOILSPART II DYNAMIC METHOD USING CONE AND

BENTONITE SLURRY

( First Revision )

Second Reprint JUNE 1990

( Incorporating Amendment N o . I )

UDC 624.131. 381

Copyright 1982

BUREAU OF INDIAN STANDARDSMANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG

NEW DELHI110002

April 1977

IS I 4968 ( Part II ) • 1976-

Indian StandardMETHOD FOR

SUBSURFACE SOUNDING FOR SOILS

PART It DYNAMIC METHOD USING CONE ANDBENTONITE SLURRY

( First Revision)Soil Engineering Sectional Committee, BDO 23

Claai",.all

Pao:r DlNUH MOHAKR'/lres"lling

Central Building Research Institute (CSIR).Roorkee

5aBI A. N. JANOLE ( Allmtal,)DR SHAlJKI K. GULHATI Indian Institute of Technology, New Delhi

DR G. V. RAo ( Altmaal, )SaRI V. G. HKODJt National Buildings Organization, New Delhi

5aBI S. H. BALCHA1'I'DANI ( AU"nale )

In personal capacity (P-820, 'P', No» Allpo".Qz/ndta 700053 )

In personal capacity (5, HunR.rjo,J Ceurt, 12/JH"II,./o'd Streit, Calcutta 700017 )

Irrigation Research In-titute, Khagaul, PatnaIrrigation Department, Government of Punjab

Radio Foundation Engineering Ltd; and Hazarat &:Co, Bombay

M_".sAUDl'J'IOKAL DJRECTOR RUUBeR Railway Board ( Ministry of Railways)

(ROSa)DuVTY DlRlECroR RESEA.RCH

(anso ) (.4llf"14I1' )Pao:r ALAI( SnfOK Universi.y ofJodhpur, JodhpurLT-CoL AVTAa SINOH Engineer.in.Chief', Branch, Army Headquarters

MAl R. R. SUDBINDBA ( ",llana,. )DR A. BANIEBIEE The Cementation Co Ltd, Calcutta

SHal S. GUPTA ( ""tmud. )SJnn K. N. DADIN...

SHIll A. O. D.uTIDAB

SRBI R. L. DEWAN*Da o. S. DRILLON

RF:lIEABCH ORICEB ( SOIL. )( IPRI) ( Altml4l. )

SR1\1 A. H. DIVANJI

( Continued 011 page 2 )

-Allo represents Indian Geotechnical Society, New Delhi

(() COPJ",ht 1982BUREAU OF INDIAN STANDAllDS

Th,. publieatrcn i. pro.ec~ed under the Indian eo,yrlgJu .4,. (XIV of 1957 ) andl'qM'odUC."OD to whole or In part by any meant except with wriuen permIssion ofdie publisher ahall be deeQled to be an infriDlemC'D' of coPyrilhl under the lIlid Act.

IS : 4968 ( Part II ) • 1976

( CQntwueJfrom page I )

Members

"JlIlI O. P. l:\iALHOTItA'>1I111 J. S. MAItYA

ReprtScnting

Public Works Depanment, Government of PunjabRoad, Wing, MlDiSlry of Shipping and Transport,

NewDdhi5J1111 N. S':N ( Alternate)

'>Hl<1 G. D, 1\1 \'l'llUIt Public Works Department, Government of UttarPradesh

S "HI D. C. Gil 'l'L'"R\ CDI ( Altemat« ),)JlIt, R. S. MJ~I.K01'E Ccnu al Water Commission. New Delhi

SHHl C, SUIIIlI~DHA ( Alternate)')1I1l1 T, 1'., NA'[AIIAJ.\N Central Road Research Institute ( CSIF ), New DelhiRI.l'It~:>JI'NTATI\F: Hindustan Construcuon Co Ltd, Bombay'j{~.'IJ';M'UI OurJn:n Buildmg and Roads Research Laboratory,

Chandigarh])11 K. R, S,XI::-iA Engineering Research Laboratory, Hyderabad'>1.Cll' T \It Y Central Board of Irrigarion & Power, New Delhi

D, l'UTY St;r'l<CT\IlY ( Altsrnat« )1oDI~ SIIA \1~III~JI PIl \KASn University of Roorkee, Roorkee

nit GOI'AL R \"fJ,\'O ( .Illernole)"1I1l1 II. V, SI{Al{)l' Irrigation Research Institute, Roorkee~l PI Hl.'/TJ.:-lJJINO LN(IDIEEn Pubhc Works Department, Government of Tamil

Nadu1:",:, I '1'1\'''' I::-H.'KEhH ( Alternat« )

Snur B. T, L'''W\IoLA Concrete Association of India, BombaySlIltt 1'. M. MI''OON (.1fternole)

'>Hm H. C. VUDI \ All India Instruments Manufacturers & Dealer.Association, Bombay

SHill V, K, VA<;cnr;\ .~s ( Alternat« ).., II III D, A,JlI II \ SI\IHA, Dill ctor General, lSI ( Ex-officio M,mblT )

DIrector ( Civ Lngg )

Seer.tary

SHRI G. RAMAN

Deputy Director ( elv Engg), lSI

Site Exploration and Investigation for FoundationsSubcommittee, BDC 23 : 2

ConDener"SHRI R. S. MELKOTB Central Water CommilSian, New Delhi

Memb,rs

SHRI C. SUDHJ!lDRA ( AltlTntd, toShri R. S. Me/kate)

PRO)' ALAM SINOH Univenity ofjoclhpur, JodhpurLT-CoL AVTAB SINOH EnSinccr.in.Cbief'. BraDch, Army Headquanen

MAl R. R. SUDBINDBA ( ..tIm"", )

( CotUiIfIIM.. ,.,. 9 )

-Abo repmcatalattitutioa or En,inccn (.Iadia), Delhi CcDtre.

2

IS I 4968 ( Part II ) • 197.

Indian StandardMETHOD FOR

SUBSURFACE SOUNDING FOR SOILS

PART II DYNAMIC METHOD USING CONE ANDBENTONITE SLURRY

( Firs t Re vision )

o. FOREWORD

0.1 This Indian Standard (Part II) (First Revision) was adopted bythe Indian Standards Institution on 22 December 1976, after the drafrfinalized by the Soil Engineering Sectional Committee had been approvedby the Civil Engineering Division Council.

0.2 Dynamic cone penetration test is a simple device for probing the soilstrata and it has an advantage over the standard penetration test thatmaking of a bore hole is avoided. Moreover, the data obtained by C01:P,

test provides a continuous record of soil resistance. The resistance­Neb, ( see Note) to penetration in terms of blows per 30 em of penetrationof the cone specified in this standard and developed by the CentralBuilding Research Institute, Roorkee, has been co-related quantitativelyto the standard penetration value .N obtained in accordance withIS: 2131-1963*. Studies with a view to establish a definite co-relationbetween Ntb, and N values for different regions of the country are inprogress. The Sectional Committee responsible for the preparation ofthis standard decided to publish this standard in the meantime so thatit could serve as a basis of test to various investigators and others engagedin subsurface exploration for foundations and thus make the results ofinvestigations comparable.

NOTE - The resistanee to penetration in the standard penetration test ( IS : 213/­1963· ) shall be designated as N, that to a 50 mm cone [Stt IS: 4968 (Part I )­1976t ] as Ned and that to a 62'5 mm cone using bentonite slurry as NCb"

O.S This standard was first published in 1968. In this revision severalchanges have been made taking into consideration the experience gainedin conducting the test and in the manufacture of the equipment. Themajor changes made relate to the material of the cone and the hammer,

·Melhod for standard penetration tell for soil,.tMcthod for subsurface lOunqin,; for soils ..'Pal t I Dynamic method uing 50 mm cone

without bentonite Ilurry.l firsl misitm).

3

IS &.61 ( Part D ) • 1'7'

and the criteria for stopping of the driving of the cone. The diameter of"the cone has been changed to 62'5 mm and the provision permitting theuse of cones of other diameters has been withdrawn. Additionalinformation has been given on the bentonite slurry used in the teat.Correlations between Nd r and N value. have allo been included.

00•• Correlation between cone penetration value. obtained using 62·5 mmcone ( No6r ), and penetration values obtained by other method. may be-developed for a given site by conducting the latter tesll adjacent( about 3 to 5 m) to the location of the cone telt. However, for mediumto fine Jands the following relationships between the standard penetrationvalue (X) obtained in accordance with IS: 2131-1963· and the conepenetration value (No.r) in accordance with method specified in thisstandard [IS: 4968 ( Part II ) 1 have been developed by the CentralBuilding Research Institute, Roorkee, These relationships when utilized..hall be used with caution.

a) When the 62·5 mm cone is driven dry up to 9 m (withoutbentonite .Iurry ):

N.., - I'S X upto a depth of4 mX.&r - 1'75 X for depths of 4 to 9 m

b) When the 62'5 mm cone is penetrated by circulating slurry:

Ne6r - N

00.5 In the formulation of this standard due weightage has been liven toInternational co-ordination among the Itandards and practices prevaiUngin different countries in addition to relating it to the practice in the fieldin this country.

0.6 In reporting the result of a telt or analYlis made in accordance withthis standard, if the final value, observed or calculated, is to be roundedoff, it shall be done in accordance with 18:2-19601.

'I. SCOPE

1.1 This standard ( Part II ) covers the procedure of dynamic ,driving ofa 62'5 mm cone and thereby obtaining a record of resistance of the soil.'The cone is directly driven into the ground and for eliminating thefriction on the driving rods. bentonite slurry is used. The use ofbentoniteslurry may not be necessary when the investigation required is up to adepth of 6 m only.

-Method for ltaDdard penetration teat for soils.tRulea for roundinl oft' numerical valuea ( rMSI~).

4

IS I .. ( Part II ) • 197&2. EQ,UIPMENT

2.1 eo••- The cone shan be of suitable steel with the tip hardened.The dimensions and the shape of the cone shall be as given in Fi!~. 1.The cone should be suitably threaded to enable it to be attached toA rods used {or driving.

r, 10 "''''

•A' SIZE DRILL AOD

VAN'S l~ THE 'LACIOF VANES A GRAVELTItA~ Milt BE ~ROYIO£DI

THAUOED

IS : 4968 ( Part II ) .. 1976

2.2 Driving Rods - The rods used for the test should be A rods ofsuitable lengths with threads for joining A rod coupling at either end.The rods should be marked at every 100 rnrn,

NOT!; - The outer and internal diameter of A rods are 41'27 and 28·57 mmrcspcun vcIv,

2.2.1 Four mild steel vanes as shown in Fig. 1 (see also 2.6) shall bewelded to the drrving rod immediately above the cone. As an alternative,a gravel trap about 150 mm high of wire gauze of 5 mm mesh may beprovided 011 the rod immediately above the cone.

2.3 Driving Head - The driving head shall be of mild steel withthreads at either end for A rods coupling (Set Note under 2.2). It shallhave a diameter of 100 mm and a length of 100 to 150 mm.

2.4 Hoi.ting Equipment - Any suitable hoisting equipment, like atripod may be used. The equipment shall be designed to be stable underconditions of impact of the hammer over the driving head when the coneis driven during the test. Provision shall be made to enable the operatorto climb up the equipment for fixing the pulley, ropes, etc. A typical setup using a tripod is shown in Fig. 2. Suitable guides shall be providedfor keeping the driving rods vertical and in position.

2.5 Hammer - The hammer used for driving the cone shall be of mildsteel or cast iron with a base of mild steel. It shall be 250 mm high andof suitable diameter. The weight of the hammer together with the chainshall be 65 kg. It shall have a hole at the centre running throughout itslength and of suitable diameter for the A rod (see Note under 2.2 ) and/orguide to pass freely through it. The clearance between the rod and/or..guide and the hole in the hammer shall be about 5 mm.

Nor» - An automatic arrangement for controlling the drop of the hammer may bepreferred if available.

2.6 Pumping Unit for Bentonite Slurry - It consists of slurry pumpof capacity 35 to 45 Ilmin at a pressure of 700 to 8)0 kN/m l ( 7 to8·5 kgf/cm 2 ) with a suction hose assembly and a swivel assembly. Forbetter circulation of slurry at greater depths a vane borer consisting offour vanes and a number of drill holes for the escape of slurry may beprovided in between the driving rod and the cone (see Fig. 1 and1"ig. 2 ).

3. PROCEDURE

3.1 The vane shall be connected to the driving rods, with the vaneborerjgvavel trap in position. The driving head with the guide rod shallbe fixed all the driving rods. This assembly shall be kept in position withthe cone resting vertically on the ~round at the point to be tested. Forthe circulation of slurry the guide rod shall be connected to a water

6

IS : 4968 ( Part II ) • 1976

swivel preferably through a flexible tube connection and then throughanother flexible tube to the pumping unit for bentonite slurry. Theswivel assembly shall be held in position by a rope passing over the pulleyprovided for that purpose. The slurry tank shall be filled with bentoniteslurry of suitable consistency (see Note). The slurry should generallybe prepared separately and stored in drums. The tank end of the inlettube to the pump shall be provided with suitable protection againstentry of debris and it shall be kept immersed in the slurry tank. Thehammer, to which a rope has been attached for operation, shall be slidover the guide rod, to rest on the driving head. A typical assembly ofthe equipment for test using a tripod is shown in FiK. 2.

NOTB - In the case of medium to fine sand, 5 percent bentonite slurry has beenfound useful, In the case of coarse sand, slurry of thicker consistency subject tocirculation requirements may be needed. In the case of hard water, addition ofI percent soap solution has been found useful to get a bett",·· suspension of thebentonite.

3.2 The cone shall be driven by allowing the 65 kg hammer to dropfreely through a height of 750 mm on the driving head. A drum typewinch fixed to central leg of the tripod may be used for lifting the dropweight provided the free fall of the hammer is not affected. The drivingof the cone and the pumping in of the slurry shall be startedsimultaneously. Driving shall not be done for more than 30 ern at atime after which it shall be stopped for a minute or two. Pumping shall,however, be continued. This helps in keeping the hole lined and alsoavoids the choking of the holes provided in the cone. The driving rodsshall be given a few turns ( about 4 or 5 turns) every now and then sotbat the hole above the cone is maintained. Efficient circulation ofslurry is necessary for eliminating friction on the rods. The number ofblows for every 100 mm penetration of the cone shall be recorded. Theprocess shall be repeated till the cone is driven to the required depth(s,e Note ).

NOTE - In order to avoid damage to the equipment, driving may be stopped whenthe number of blows exceeds 35 for 100 mm penetration when the cone is driven dryand 20 for 100 mm penetration when the cone is penetrated by circulating slurry.

4. REPORT

4.1 The number of blows (NCb,.) should be reported as a continuousrecord for every 300 mm penetration either in a tabular form or as agraph between N. and depth. Records of the test shall also includethe following:

a) Date of probing;b) Location;c) Elevation of pouncl-eurCace;

7

u .... (Part D)-I".

d) ~epth o.f water table and itl likely variation, from availablemfOrmabOnj

e) Total resistance at the required levels;f) Any interruptions in probing with reasons;g) Any other information available, for example, type of loilj andh) Diameter of the cone used in the test.

110'1"" 1101.11..,Wlwe.

1.,BOIl! IIOLf

Olll'l1llG 1100

YAN! 1011£11

CON!

FlO. 2 A TYPICAL SET Up FOR DYNAMIC CONE PENETR....TION TEST

8

IS I 4968 ( Part II ) • 1976

Hindustan Construction Co Ltd, BombayRoads Wing, Ministry of Shipping & Transport,

New Delhi

R,pr,senlingCementation Company Ltd, BombayPublic Works Department, Government of Uttar

PradeshRodio Foundation Engineering Ltd; and Hazarat &

Co, BombayRailway Board ( Ministry of Railways)DEl'UTY DIRECTOR RE811:ARCH

(FE) (ROSa)ASSISTANT D I R III C TOR

RES EAR C H ( SOILS )( RDSO ) ( Allmlal, )

DIRECTOR Maharashtra Engineering Research Institute, NasikRIllSEARCH OFFICER ( Alumat« )

DIRECTOR GENERAl, Geological Survey of IndiaSUBI S. K. SHOlrIE ( Alumat« )SHBI P. N. MEHTA ( Almnal, )

EXECUTIVE ENGINEER (SOIL Public Works Department. Governrnent of TamilMECHANICS DIVI8ION) Nadu

SHBI T. K. NATARAJAN Central Road Research Institute (CSIR ). New DelhiSHRI H. R. PRAMANIX River Research Institute. West Bengal

SKRI H. L. SABA ( Alternate )REl'ltESENTATIVESHRI N. SEN

SHRI R. C. DESAI

( CotdinwdJrom pag' 2 )

M,mbns

DR A. BANERJEEDR A. K. CHATTERJEE

SKRI P. K. THOMAS ( Altemat« )SUPERINTENDING SURVEYOR OJ' Central Public Works Department, New Delhi

WORKS (I)SHBI D. SHARMA Central Building Research Institute ( CSIR ),

RoorkeeSHKI V. S. AOGARWAL ( Alt,rnat,)

SHRI H. C. VERMA Associated Instruments Manufacturers India Pvt Ltd,New Delhi

PsOI' T. S. NAO....l\AJ ( Altmult, )

BUREAU OF INDIAN STANDARDS

261 71

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