geotechnic (consoliadation)

8/20/2019 Geotechnic (Consoliadation)

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CONSOLIDATION

TEST

MOHD AMRI BIN RAMZICF 140081


2/19

Consolidation Settlement

• It occurs due to te !rocess o" te consolidation#

• Cla$ and Or%anic soil are most !rone to consolidation

settlement#• Consolidation is te !rocess o" reduction in &olume

due to lost o" 'ater under an increased load#

• It is a time related !rocess occurrin% in saturated soil($ drainin% 'ater "rom &oid#

• It is o"ten con"used 'it Com!action#

• Consolidation teor$ is re)uired to !redict (ot rateand ma%nitude o" settlement#


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*at is Consolidation+

• *en a saturated soil is loaded e,ternall$- te'ater is s)uee.ed out o" te soil and te soilsrin/s#


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Conce!t o" Consolidation

• As te time !asses- te 'ater comes out o" tesoil &oid and so te &olume o" soil decreases- tisis cause o" te settlement#

The decrease in volume of soil = The volume of

squeezed out water


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Settlement due to

consolidation

• Settlement is te &erticall$ do'n'ard mo&ement

o" structure due to te srin/a%e in &olume o" soildue to consolidation


6/19

Settlementoid ratio

Relation• 2)uatin% te t'o e,!ression "or a&era%e &ertical

strain-


7/19

Settlement &s# 3ime• 3is leads to settlement occurrin% o&er a lon% time-

'ic could (e se&eral $ears- de!endin% u!on te!ermea(ilit$ o" te soil


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Oedometer test

• 3e soil caracteristics durin% onedimensionalconsolidation or s'ellin% can (e determined ($te oedometer test#

•An oedometer test measures asoil5s consolidation !ro!erties#

•Oedometer tests are !er"ormed ($ a!!l$in%di6erent loads to a soil sam!le and measurin%

te de"ormation res!onse#• 3e results "rom tese tests are used to !redicto' a soil in te 7eld 'ill de"orm in res!onse to acan%e in e6ecti&e stress#


9/19


10/19

Conce!t

• Oedometer tests are desi%ned to simulate te onedimensional de"ormation and draina%e conditions tat soilse,!erience in te 7eld#

• 3o simulate tese conditions- ri%id con7nin% rin%s are usedto !re&ent lateral dis!lacement o" te soil sam!le#

• :orous stones are !laced on te to! and (ottom o" tesam!le to allo' draina%e in te &ertical direction#

• 3o (etter simulate onedimensional strain- a diameterto

ei%t ratio in te sam!le o" ;


11/19

M23HOD 3O D232RMIN2 3H2 CO2FFICI2N3

OF CONSO=IDA3ION

• 3ere are t'o metods "or determinin% te coe>cient

o" consolidationcient o" consolidation can (e determined ($tis e)uation-


12/19

3a$lor metod


13/19

Casa%rande metod


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32S3 :ROC2D9R2

1#Measure te internal diameter ?D@ and te ei%t o" te rin%- usin%

internal &ernier cali!ers#E#*ei%t te rin% to te nearest 0#01% ?mR@#;#Cuttin% te s!ecimen and trimmin% into rin%#4#Determine te initial moisture content "rom trimmin% soil##Determine te 'ei%t o" rin% and s!ecimen ?m1@

#Determine te mass o" (ul/ s!ecimen ?m@ to te nearest 0#01%usin% tis e)uationm G m1 mR

•.


15/19

32S3 :ROC2D9R2

#:lace te consolidation rin% and s!ecimen ?cuttin%ed%e u!!ermost@ centrall$ on te !orous disc#8#Fit te rin% retainer and cell (od$ and ten !lace

te u!!er !orous disc centrall$ on to! o" tes!ecimen#

#:lace te consolidation cell centrall$ in !osition onte !lat"orm o" te macine (ase#

10#=i"t te end o" te (eam to allo' te loadin% $o/eto (e raised to te &ertical !osition and adJust te

loadin% stem ($ scre'in% it do'n'ards until teend en%a%es closel$ in te recess on te to! o" teloadin% ca!

11#Attac te com!ression dial %au%e to te arm onte su!!ort !ost#

1E#Add 'ei%t ?E# /%@ care"ull$ to te load an%er


16/19

32S3 :ROC2D9R2

1;#Add 'ater at room tem!erature to te celland ma/e sure tat te s!ecimen and u!!er!orous disc are com!letel$ su(mer%ed#

14#*ind do'n te (eam su!!ort and at tesame time start te cloc/#

1#O(ser&e te com!ression %au%e readin%sand te cloc/- and record te readin%s on aconsolidation test "orm at te selected time

inter&als#1#:lot te readin%s o" te com!ression a%ainst

time to a lo%aritmic scale and a%ainsts)uareroottime#


17/19

SI=3 C=AK R2S9=32LAM:=2


18/19

SI=3 C=AK R2S9=32LAM:=2


19/19

Conclusion

• Consolidation is a !rocess 'ic soil decrease

in &olume#

• Occurs 'en stress is a!!lied to a soil tatcause te soil !article to !ac/ to%eter moreti%tl$- tere"ore reducin% its (ul/ &olume#

• Oedometer is one o" te e)ui!ment tat use"or determinin% te consolidation !arameters

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