Unconsolidated Undrained Triaxial Test

CVE20004

UNCONSOLIDATED UNDRAINED  TRIAXIAL TEST

UNCONSOLIDA UNCONSOLI DATED TED UNDRAINED TRIAXIAL TEST

ASSIGNMENT NUMBER :4 CREATED BY : HARINDER SINGH REHAL STUDENT ID NO :

Due date : 16/10/2015

CVE20004

UNCONSOLIDATED UNDRAINED  TRIAXIAL TEST Introduction In unconsolidated undrained test samle is not to drain ! T"e samle is comressed at a di#erent rate ! t"e UU test is alica$le to undistur$ed samle in %"ic" no c"an&e in moisture content 'rom out site can $e ermitted ! test can $e carried out o(er a ran&e o' moisture content to ena$le )o"r en(eloes 'or t"e re*uired to $e interolated ! UU test rocedure is use'ul 'or determinin& t"e total stren&t" arameter 'or soils t"at "a(e su#ered distur$ances or moisture c"an&e durin& samlin& !

Ai  To stud+ t"e s"ear stren&t" $e"a(iour o' a cla+ t+e soil usin& t"e tria,ial aaratus under undrained conditions usin& a multi-sta&e testin& aroac"!

!rocedure •

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.amiliarise +oursel' %it" t"e mec"anics o' t"e tria,ial testin& aaratus!  Record t"e details o' t"e cla+ samle / dimensions and %et mass in order to determine t"e %et densit+1!  Set u t"e samle 'or testin& 3lace t"e c+lindrical cla+ samle on t"e $ottom late o' t"e tria,ial aaratus and co(er %it" t"e to loadin& late! T"en t t"e ru$$er mem$rane o(er t"e samle and to loadin& late1! Use o-rin&s to seal eac" end o' t"e samle and t"en osition t"e tria,ial cell and loadin& ram o(er t"e samle! .lood t"e cell %it" %ater5 maintainin& a small amount o' air in t"e to o' t"e cell to ena$le ressurisation!  Al+ t"e cell ressure 671 Once t"e tria,ial cell is near 'ull o' %ater5 al+ t"e cell ressure or connin& stress1 $+ siml+ releasin& ressurised air into tria,ial cell / 800 93a 'or t"e rst sta&e o' t"e test!  Al+ t"e de(iator stress 68 / 671 Start t"e a,ial loadin& motor and record t"e load rin& readin&s 'or eac" 0!:; mm o' (ertical dislacement5 or 'or e(er+ 8< strain o' t"e samle! Continue t"e test until t"e samle 'ails t"e corrected de(iator stress reac"es a ma,imum (alue1! Increase t"e cell ressure to 200 93a to allo% t"e samle to 'ail a&ain i!e! multi-sta&e testin&1! Once t"e samle 'ails under t"e increased cell ressure!  Reeat ste = 'or a 'urt"er increase in cell ressure to 400 93a!

CVE20004

UNCONSOLIDATED UNDRAINED  TRIAXIAL TEST •

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 Remo(e t"e samle at t"e end o' t"e test and o$ser(e t"e 'ailure mec"anism o' t"e soil samle! S9etc" t"e 'ailed samle / notin& an+ s"ear lanes or $ul&in& resent! Tr+ to measure > estimate t"e an&le o' t"e s"ear lane at 'ailure! Determine t"e moisture content5 %et densit+ and dr+ densit+ o' t"e soil samle!

A de"cri#tion o$ t%e "a#&e ' in accordance (it% t%e terino&o)* u"ed in AS1+26 ?ased on AS8:2= samle is Dar9 $ro%n 5 moist 5 rm 5 med "i&" %it" lasticit+ cla+ !

Data Ta,&e Longitudinal Strain vs. Corrected Deviator Stress for Multi-Stage Testing

Cell Pressure (kPa)

100

Longitudinal Deformation ( x 0.01 mm) and Longitudinal Strain (%) of  sample 0  10 $$ 00  &0 $ +00 + 0 *$ ,00 , 100 11$ 1$00

Deviator  Stress Calibration and Corretion !ator 

0   &.&0 1%   &.* $%   &.0 %   &.+ &%   &.&1 %   .&.$+ +%   &.11 %   &.$,+ *%   &.$*1 ,%   &.$+ 10%   &.$$ 11%   &.$ 1$%   &.$$$ 1%   &.$0 1&%   &.1, 1%   &.1* 1+%   &.1+

Stage "o. 1 Stage "o. $ Stage "o.  (Cell Pressure # 100 kPa) (Cell Pressure # $00 kPa) (Cell Pressure # &00 kPa) Load 'ing 'eadings (Divisions)

Correted Deviator  Stress (kPa)

Load 'ing 'eadings (Divisions)

Correted Deviator  Stress (kPa)

Load 'ing 'eadings (Divisions)

Correted Deviator  Stress (kPa)

0

0

0

0

0

0

80 8= 8@ 8:

7@!=: =8!== =!84 =;!0: 20 27 24 2; 2=

:=!7 @:!47 0!2 4!4 :!@7 72 74 7= 7= 7: 7: 7:!;

88! 82:!7; 874!07 877!;= 87=!@8 87=!72 87:!==

CVE20004

UNCONSOLIDATED UNDRAINED  TRIAXIAL TEST 1$ 10 1&$ 100 1 1+0 1$ 1*00

1% 1*% 1,% $0% $1% $$% $% $&%

               

7@ 7@ 7 7 7 7

&.1&* &.1 &.11, &.10& &.0*, &.0& &.0+0 &.00&

87 87@!4 848!=; 848!84 840!=2 840!88

-ra#% "%o(" t%e re&ation"%i# ,et(een corrected de.iator "tre"" ." &on)itudina& "tre"" 

Corrected De.iator Stre"" 0"/ Lo)itudina& Stre"" 8=0

840

820

800

Corrected De.iator "tre"" 12!a3

@0

=0

40

20

0

CVE20004

UNCONSOLIDATED UNDRAINED  TRIAXIAL TEST

Re"u&t Sa#&e NO :

Stre"" 41

8 2 7

800 200 700

Di"cu""ion / conc&u"ion

Stre"" 1Stre"" 4 =!84 :!@7 848!==

Stre"" 11 8=!84 2:!@7 ;48!==

CVE20004

UNCONSOLIDATED UNDRAINED  TRIAXIAL TEST Value 'or C B 20 9a5 Value 'or  B :!; de&ree 'ollo%in& e*uation $een roduced to c"ec9 t"e result o' )o"r circles o' eac" sta&e ' B 20  Stress n1 tan:!;F!  T"e e,eriment reac"es t"e aim %"ic" %as to stud+ t"e s"ear stren&t" $e"a(iour o' a cla+ usin& unconsolidated undrained tria,le test! Gand lottin& o' cell ressure and de(iator stress s"o%s t"e 'ailure oint o' all 7 stress and result $ein& calculated as Value 'or C B 20 9a! T"ree di#erent test $een conducted to nd 'ailure stress usin& di#erent normal stress! A'ter all lottin& line o' $est $een dra%n tan&ent to circle to nd out t"e 'ailure stress and result reresents t"at 'ailure stress occurred onl+ at 400 Ha and 200 9a ! .rom t"e &ra" can $e seen t"at corrected de(iator stress (s lon&itudinal stress are $ot" linear and nonlinear "o%e(er as lon&itudinal stress increases so does corrected de(iator stress increases too ! )o"r circle 'ailure &ra" $een dra%n on t"e 2 di#erent scales Goriontal scale is 8;0 and (ertical scale is  880!