2. SIMPLE SOIL PROPETIES

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Rolf Evans
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1 2. SIMPLE SOIL PROPETIES 2.1 EIGHT-OLUME RELATIONSHIPS It i oft rquir of th gotchical gir to collct, claify a ivtigat oil ampl. B it for ig of fouatio or i calculatio of arthork volum, trmiatio of oil typ a phyical oil paramtr ar routily coutr i practic. Soil paramtr ar trmi by rlatig th cotitut of th ampl. hav that oil ar ucmt or akly-cmt accumulatio of miral particl ith voi pac bt th particl fill ith air a/or atr. A a rult, oil ar thr-pha ytm coitig of oli, atr, a air. Th ight-volum itrrlatiohip bt th pha ar importat i urtaig th bhavior of a giv oil ampl. Th thr-pha ytm of a giv oil ampl ca b rprt by th block iagram ho i Figur 2.1. Air a v atr Soli Figur 2.1 Thr pha of a oil lmt Th total volum of th oil ampl a ho i Figur 2.1 ca b xpr a + v + + a (2.1) hr total volum of oil volum of oli v volum of voi volum of atr i th voi a volum of air i th voi Sic th ight of th air i th voi i gligibl for practical u, th total ight of th ampl i + (2.2)

2 hr ight of th ampl ight of oli ight of atr Ba o Eq. (2.1) a (2.2), may rlatio ca b vlop a icu hriaftr. Th volum rlatiohip commoly u for th thr pha i a oil lmt ar voi ratio, poroity, a gr of aturatio. oi ratio () i fi a th ratio of th volum of voi to th volum of oli, i.. v (2.3) oi ratio i uually xpr a a cimal quatity. Poroity () i fi a th ratio of th volum of voi to th total volum of oil, i.. v (2.4) Poroity i uually xpr a a prctag. Th gr of aturatio (S) i fi a th ratio of th volum of atr to th volum of voi, or S v (2.5) Th gr of aturatio of a oil i uually xpr a a prctag. If S100%, th oil i ai to b aturat or fully aturat hra if S0 th oil i ry. Th rlatiohip bt voi ratio a poroity ca b aily riv from Eq. (2.1), (2.3), a (2.4) a follo: Thu or v v v 1 v v 1 1 Th commot ight rlatiohip icluig ight of cotitut of th thr pha ytm ar moitur cott, alo call atr cott, a uit ight. Moitur cott () i fi a th ratio of th ight of atr to th ight of oli i a giv volum of oil. (2.6) (2.7) (2.8)

3 Th moitur cott of a oil i fou i th laboratory by ighig a ampl of oil a placig it i a ov at 110±5ºC util a cotat ight i achiv; that i, util all por-atr i riv out. For mot oil thi proc complt i about 24hr. Th oil i th rmov from th ov, cool a th igh. Th iffrc bt th origial ma a th fial ma aftr ov-ryig i th ma of atr that vaporat. Th fial ma i th ma of oil oli oly hich complt th proc. Uit ight (), alo ko a moit or bulk uit ight i fi a th ight of oil pr uit volum, i.. (2.9) If furthr xpa th abov Equatio, (1 + ) (2.10) Part of th lat quatio, i.. i hat i ko a th ry uit ight,. Thu, (2.11) Th ry uit igh i oft u to olv arthork problm ic i uch itac it i cary to ko th ight pr uit volum of oil, xcluig atr. Subtitutig Eq. (2.11) ito Eq. (2.10) a rarragig, obtai, (2.12) 1 + Sic uit ight i xpr i kilo Nto pr cubic mtr (kn/m 3 ), it may omtim b covit to ork ith ma ity (ρ) of oil xpr a kilogram pr cubic mtr (kg/m 3 ). ca thrfor rit Eq. (2.9) a (2.11) a, M ρ (2.13) M ρ (2.14) hr ρ bulk ity of oil (kg/m 3 ) ρ ry ity of oil (kg/m 3 ) M total ma of oil ampl (kg) M ma of oil oli i th ampl (kg) total volum of th ampl (m 3 ) Saturat uit ight ( at ) i th bulk uit ight of th oil h it i fully aturat. at at (2.15)

4 Submrg uit ight ( ub or ') i fi a th uit ight of aturat oil ( at ) miu uit ight of atr. It i thu th uit ight of aturat oil, urrou by atr, pr uit volum of oil. ub at (2.16) Som commo oil typ ith typical valu of uit ight ar prt i th tabl blo. Soil typ at (kn/m 3 ) (kn/m 3 ) Gravl Sa Silt Clay Spcific gravity of oli (G ) i fi a th ratio of th uit ight of oli to th uit ight of atr at 4 C. I othr or, it i th ratio of th ight of oli to th ight of atr of qual volum. Thi phyical quatity i oft rquir for variou calculatio i oil mchaic. G (2.17) Th pcific gravity of mot oil fall bt 2.6 a 2.9 a i mot ituatio it coul b aum to b qual to 2.7 ith littl margi of rror. Th uit ight of atr i uually tak to b 9.81kN/m 3. Th lab apparatu rquir to trmi th pcific gravity of oil ar ho blo

5 Durig th pcific gravity tt, th firt tp i to igh th pycoomtr a rcor th valu a m 1. Th plac a mall quatity of oil ii th pycomtr a igh th pycomtr ith th oil a rcor thi ma a m 2.Som -air atr i a to th oil i th pycomtr. Th pycomtr i th agitat to rmov air bubbl from th oil voi. h all bubbl hav b rmov th pycomtr i fill compltly ith -air atr. Th ma of pycomtr, oil a atr i trmi a rcor a m 3. Th oil a atr ar rmov from th pycomtr a th cotair i thoroughly cla. D-air atr i a to fill th pycomtr a th ma of th pycomtr a atr i trmi. Lt thi ma b m 4. Th ma of ry oil i th m m 2 m 1 Th ma of atr iplac by oil oli i m 5 m 4 m 3 + m Th pcific gravity of oli i th G m /m 5 Rlativ ity (D r ) i commoly u to crib th i itu or loo of graular oil. It i fi a max max D r (2.18) hr D r rlativ ity, uually giv a a prctag i itu voi ratio of th oil max voi ratio of th oil i th loot tat obtai i th lab by pourig ry oil ito a moul of volum 2830cc uig a ful. mi voi ratio of th oil i th t tat obtai by vibratig th oil ith a ight impoig a vrtical tr of 13.8kPa for 8 miut at a frqucy of 3600Hz a amplitu of 0.064mm. Th valu of D r may vary from a miimum of 0% for vry loo oil to amaximum of 100% for vry oil. Soil gir qualitativly crib graular oil poit accorig to thir rlativ iti a ho i th folloig tabl. Rlativ ity (%) Dcriptio of oil poit 0-15 ry loo Loo Mium D ry Uig Eq. (2.1) through (2.17), o ca riv iffrt itr-rlatiohip. mi a) Rlatiohip bt, S,, a G G S (2.19) b) Rlatiohip bt, G, a

6 ( ) G (2.20) G 1 + (2.21) ( G + ) G (1 + ) at for S 100% (2.22) G ( G 1) ( G 1) ub (2.23) G c) Rlatiohip amog,, a G ( 1 ) (2.24) G ( 1 )(1 ) (2.25) at + [ 1 G ] ( ) + (2.26) ( 1 ) for S 100% (2.27) G

Solutions to Supplementary Problems

Solutions to Supplementary Problems Solution to Supplmntary Problm Chaptr 5 Solution 5. Failur of th tiff clay occur, hn th ffctiv prur at th bottom of th layr bcom ro. Initially Total ovrburn prur at X : = 9 5 + = 7 kn/m Por atr prur at