Estimation of In-situ Bearing Capacity of Soil b~ a . ---_-_ --Specially Designed Hand ._ _ Penetrometer 0 - . - ___.I__ C - ! i I 31 " I :-- '!.At- vzc ofa ximple oed i n c ~ ~ e . a t i v r ) . ~ m a l p e n e ~ r o Jor m e fajair e~ wst?~~rnknr if in-sifrr benz;rtg capncily c?!'~saU ~ X L B bee^ de.rcribad, Currelm~g with rllrk. aundwd prmtraliurs leu!, N Palun /rule been worked mt ofid a fn!>le A m been prc'pnrrd for txriri~~ding bearing capacities o f c d r s i v e and ,qrciriulnr saib t Jionr the 'PIH' voI~(es obtain~d by ihe k;.rrrd pme/romctcr. The torrelafed values ore irr c l o ~ rJgrecZ~ . G P Vwfrk I 114e 'EJK';valsrt.s d t o i n d at a majt~rcnnrfmcfiun sire. n!;mhcr of b l o w required tion uf S E T cquiptnent for 30 crn pen-tia- PifI -=. nur;?l-p,r a F blows required for 30 cm jxnctza-' I I I r.i,n uf hand wnctromctcr quic!kly a:Mhcr tbe spcifjcd v d u t is avaiiabie or not. lllntlisturlnd soil samples could undoubtedly be iakcn for htwr~tory tests. but the time involvtd in the p r w u wo11Jd d e it rather impractiml. Besides, odw sn or : ? , : sci! cxckvatiun is wadc, i t wmnot 'bc lefi wollld deteriorate duc to rain, seepage, etc. Moreover, I I I -1 c, = . pnetzsiion per Mow for' hand pzmclrornctcr :or grznuiar' soiir. undisrur*mcixamr;ie-, arc ;;;,I posriiii~. lm-.~jtuLCSLI such a 3 SPI" (Standard Pcoc!ratioa '6czi), Hate hati Tesl' arc cven more timc-cons~lrr,iingaarl Car tnc) expensive to make t k l n a practical proposition. ' Eleras, tosvercomc these rPi&ullics. tkauehor has de.rig o l d la spc~&l hid penetromcter qxbir-la in extremely siniple to hslndlc z,md operate. -la can &o bc uwd for any typs of soil. k, it, 2- ki<>p of h m n ~ e r for SF[ equipma.nt = 75 C7n (.Elk .-: drop o l wcipht for Ra11d pnetromettr = 34.5 --. YJ.';.== v;etgt~t or kmrnmsr for S P T equ:pment ,-. / : : , " , weight of s t e t 1 disc = 10 kg /dl . scclinml arca of SFT Goon19.6 cma /. A, . sectional arm o f t h e MS rob of hand pnrtr-+ - 65Lg - meicr = 4.9 cma Thc penetromctcr is made from a 25 rnm dia h'lS rod 1.5 m in length (Fig I ) . On? end OF the rod is b p i ~ c dtu a ~-oacwlrilc the othcr end is thrcadcg. The length of the thiead:e<i portion .isaround 20 cm aud tlrat of the tnpercd portion is 5 cm. A collar is wcld~td to the middle third of the rod. A, circular stml di.sc weighing 10 E r g is allowed to slide frcely through the rod. A.n adjuiabIe nut is then plar;.cd oa the top t h d r d p~rlion. Tke bottom 5 0 crn of thr: rod including tile brprcd portion is allcrgatcly p i a t e d yello~vaurl Mack f i x 5c m s?.pmita. I I I I ' \ '1%:~ s;ite: cr~ginceri!: nlPtn faced with the problcrln o f of $oil. A never r:.jver ax cnrirs ~ i t c , T& rwmxu.mcd;lbiom obtained I r m ,Gb@5;3iS il.iw~$g:,:i~p. 2x.a t.km$a@j of+ m&ze, E c h J oa rbc 3zr;;r~~rzix oWa.lor.l a&! tnw& ~ 3 ~ 2 i ~ l r i i lt i rh 1~ ~ (n-sdrw h a r i n g capcity p(?ii ayrvcy, 1.113 PIIC!~C.T 3 1 0 ~ dctaiied, can I?..BODEOF ORFXATIOlY The Test 00 W l k b tb & t&g~ 9 p g & ! I ! ! .----__ -.-ZL S % o ? a l k i s i l h ?A iJj:h$$,luaanidC~ : p d ~ 3 L l l b * Q l c & ~ 3 . ,. iX1,3:-n;w?w-slrr+r.:!rrid 03 Dsetzx~&eyS, Lfr'&:$, s,%Jvar 3 r g s . s t d :tiid81wugd a! 1 % ~ ~ ~ ~ i - A o o n F6@s k S , M&?+F~'^J BZ:4 $ 4 h - e zz-y;& i p > - T . ---- r i: w h fiuiv,-qf:v~nljyeltr.-ilied in t bc - ' r s w i o p . But tk:~: u r d ;srob!/.rt., l I c s witla tkc si%eeii.;:;sr.~r who h . 8 ~ lo vr.iiCy p . 5a E $& _ pt?-v;nt rnovemnnt oC the: arigind nvt.. Tbe iz~tru~t1rr.11 !hus r e t ia tRr.il t~clrl vcrtica.lly by nr?c petson ( 0 the -. ~FC&.IA~. d i m i s ilk3 t8sotq;b. the rod LO. w t l M wllrr. Thc nut Ir thtx nrfjnttA .pi:, ~ c m from the tog aS khc *:?4c (Fig I) h a tbs a ~ 1. r eW:ly 37.3 cm. A s b ; k OD & ~ p of t j ~ e p t v i ~ u onc s ia prefer,~.b!e. %re will L U & &,'.4.b$, 9'8E7 For intcrxnedi~ico ~ i lyp?::.E I CORRELATION W I T l i .)I. rsou' .~. considering t h e penetromcter~ botb cases.O?.3.tl?lr: ~ ' A P . yrese~s(cii i. P is elim:nated Iruh. depth foe n SET equipment.PLAN A & R u t the rcsisLznce of soil.6 SIT N values o f the mil.' .-+J where P is the .g ignorcd to allow for any soil disturbance. .ht t a thc Pop oi ?he coiinr.:$ -7- . CORRELATION %VlI'H SrANDAUD PENETR.rhutldatian i:. rh... <7 7-i3 %iB ' wlatiuns ms bc I ~ c I ~ . U . A record wi!l h e : kept for the number of blows req~lircd Sase!! on this relationsliip.i . This tcst is carried out basically Very l o o x t o ascertain the relative density and bearing capacity of granular dcposit~'.srrr s si-: - x i d. I ii .<lj . The number of blows requircd for the pcnctratioa of the last 30 cm 5 . : ~ . However. .:~ a g ~ ~ . of the rod is taken as rhc :vH value of the particular pnctromcter.D:I.irzn for purely E ~ a r l i l i r .r.!. spot w:lcrc the test is requircd A second persoil i s thcn required ro lift rhe disc slowly up to the b ~ t t ( ~ m 06 the n u t and allow it to F ~ l ifreely from thne lirig. which msumcs that tbc driving encrgyic absorbd by the penetrometer.weight of penetronl P deyends on the weight of .Y.: ul:ilnnrc bearing upacity of soil m u 1 be the same for bolt: rhc C. 7 w fl Piam . Using thc Dutch formulaa. that 15. t t ~ r :iu:nbcr ol bitj. f..V values required are also pccscntcd..~ i a t i c m s Pro B.s!B <. c blows required for the initial 15 cm penetration is t r i ~ r i n g capacity of a par~icu1a. Sh. I:j. i irilci'- 44 ?.S A F E BEn.'. I.q 'Table I..> 93 - il(M& : C o r . The Standard Penetration Test (SBT) is ~ndispensablr f o r any soil investigation and its usefulness cannot be overcmphasited.C!SCS Tbcrcfore. I ( : I T ~ I'OR 1.>.I'. The type o f soil and the corresvorjdi~.idiuin dcc3r: d c bearing capacity of any rype of roil o n be obtained f r 6 6 i .>. .. The nunher of reguireci Lrom the band pcncrromelcr 1'.vs 5:dr n For each IS cm pcnctration of the rod. A comhaioo arc:~a between thc SET hTvalucs and tbc NA'vaIuas ohbinnl Vriy from the poablc' hand pnctromcter is prcseoted.5 k l S Q U A U OR VJIDE FOCl\.4TION TFST TAB1.! .s y r o ~ e d u r e i s repa!ca ~ n t i the l rod has penrir~ted45 crn into the soil. Since ihc term aud varics with y shallaw depth weightless for 'cn (I). correlations also LmsZ exist Between SIT N values and U o c o d n e d Comprcssivc Strengths of cohesive soils. c l ~ c o l % ~ ~soils o only. I-in rb . an idea of the b. Thus.' . particularly .go'i. TITI{ .ri i:X~)lL. H J G i b b and W G H. ' R e a r c h on Dc~cr. IS : 18RB.rcs~1i~ely. it m u t be empbsized that the hand penetrometer should not be used without a prior ipvestigation of the subsoil.c :'I and 5 3 Area ? :I.vtf VALUES V H VALL'? . for their vlluable comments.L ~ G Sby s9wn Penetration Testing'. Lib=.i ~~~~~~. . . 1981..w:Cc:a! dcpuhirs.IC)82. I d a n Sfardor& h r r i l ~ u mIR . a d ~ .: . R m l m m C l B . 0 ~ 1 1 Shri Sanyal obtained BE (Cinl) rram Sc B ~ ! @ Enginwring alles. and Ballour B u t ~ y Ho has been the Engineer-inCharge of soil invcsi ation.- * R denole3 refusal.ubit'iin. and from 1967 to 1971 with M/s L G Moucheland Partners & Grnpany (UK). S.4. ~ f l ~ r l t ~ % :m ' I.V V&LI!E I I UJO(:IRFD/ I H t I C.21. However. p 2IV. --Z ? . over. He hasbeenatfociatcdfrom I Y ~ J ~lv67 O with W SAlklns & Partners(1ndia)ttd.4 n>ilrna~nlr cnllcrtrc Mos~ly granular Granular a .. 2nd rcvlslon. 1982. v~11 1.&ht Soils E o & m with M I ! X I N r)ragl. p 8 6 . > SHU FOR TIIP Arcir I !.. that is.<.he k'u. 'Method o f Load 'la~ or~ Soils'. Cirnw The hand penetrometer is an useful tool for a reason.H~FLA~~II D I r ( .7ltz. P 35. .i. -lndion P R A m C U APPLICATION The penetrometer has been a m3j0r construction site for verifying the specified safe bearing capacity of various foundations. Vtncruelan 1. the instrument can be useful.amitii Mcchlnia i n fn. hir HillB~wkCu.\RT G AT r H F F ~. It is a complimentary tool only to be used in areas where the depth and thicknesses of various soil strata have been determined by proper soil investigations.S i.I :li. : Area : :. slr. The results are given i n Table 2.FVFL L)rrlc:u 4 R~ ~ A L~I V U . :nJedi!iori. k h t r m k y t sons.~ I.~ : ~2:. :I and :J C.to Shri S R KuIkarni and Shri C P Nazir. 5. 4.. Presrbnrly la is bRc. 'Founjation Analysis a n d %in'..hor - Stri K L s . ~k~ P ~ T ~ : I ~ .A?S~-I~ f -Y '~b . For lightly loaded s h l l o w foundations.rnii~inp :he De:~siiyof S . moro than LOO blows for 25 mm penzrn~inn. It can also be used for compaction control and in highway engineering for the determination of suitable subgrade. More. .inec:ing Precticu'. :~ i < : . R• :I 103 C-+ mil Cohuivt to1l :O IS R* I6 51) 35 211 Granular Cohesive C-+ soil 20 -.m and Ltd and rerpowbk f o r In slrv boarlna c a p m t r e a of p i l a and major foundations for tha Visikhamtnan Stocl ~~ Proj~t. 'Motbod for S I . Ir is particularly useful to the s i t 0 cuginccr to determine the btxring capacity of the excavated strata.~~~~(t~. M h a h EnJossr for road pmjsir in F k s m r i . frh I C S ~ ~ F E . iocluding geolshnical stat1 plant and tba Principal Soils & ' ACI(FJ0WLEDCMENT T h c author is thankful to his colleagues. .1971 and I9SD.. G:. R w t n r i o oT e a for Soilr'. care should be taken in the interpretltion of Table 2 as the results are sensitive to the type of soil encountered. J CONCLUSION E Bnsles. ably good assessment of the bearing capacity . IS :2131-1981. They are in close agreement with the correlated values presented in Tablc I.ondon-Cambrid~mo~orwry. remaon. 2nd edirion. 1957. Srurdordr inriiru/ion. slnptr . Alwrirn ial plant.rABLE 5 2 COMPARISON OF SPT A ' VALUE.sCollegein 1964. ~ . 1967.l .' Cbwony. 3... .Mechanics)and M Phil from Vnivtrslly of LondonKing.