Lab 3

Andrew Chapman – asc2172 Soil Mechanics - Wednesday Group

Soil Mechanics Laboratory eport Lab !2 – Atterber" Limits #$ #%&'()C&#'%*  &he purpose o+ the Constant ,ead ermeabilit ermeability y &est &est e.periment e.periment is to determine the coe/cient o+ permeability permeability +or an un0nown sample o+ sand$ &he coe/cient o+ permeability permeability is a coe/cient which helps describe the ow o+ water throu"h soil$ &he coe/cient o+ permeability was determined e.perimentally e.perimentally as well as analytically these 3alues were then compared$

##$ (#SC)SS#'%*  &he constant head permeability permeability test is a rather simple simple procedure$ procedure$ A cylinder o+ soil is soa0ed until +ully saturated$ &hen it is attached to an apparatus such that tubin" is comin" out both ends o+ the cylinder4 one +or inow and one +or outow$ outow$ Water is then poured into the inow tube at such a rate that the water hei"ht and there+ore head pressure pressure remains constant$ As water ows out o+ the outow tube it is collected while time is simultaneously measured$ &he hei"ht between the maintained hei"ht o+ the water in the inow tube and the hei"ht o+ the outow tube is then measured to determine determine the head di5erence$ &hese 3ariables can then be used to calculate the coe/cient o+ permeability$

###$ 6S)L&S*  &he dry density o+ the un0nown sample was was determined to be 1$8 1$8 : "9cm $ &he 3oid ratio o+ the un0nown sample was determined to be ;$7;:$ &he coe/cient o+ permeability was e.perimentally e.perimentally determined to be ;$;181: cm9s$ &he data leadin" to this result is summari=ed in ?Appendi. A@$ )sin" the Chaupis method4 the coe/cient o+ permeability was +ound to be ;$;11Bcm9s$ ;$;11Bcm9s$ )sin" the )$S$ (epartment o+ %a3y method4 the coe/cient o+ permeability permeability was +ound to be ;$1 cm9s$ Calculations are summari=ed in ?Appendi. @$

Andrew Chapman – asc2172 Soil Mechanics - Wednesday Group #D$ E)AL#&A&#D6 6' A%ALFS#S*  &here were se3eral sources o+ potential error in this laboratory e.periment$ &he rst source o+ error was in the maintenance o+ a constant head di5erence$ #t is 3ery possible that the e.perimenters +ailed to pour water into the +unnel at a rate that would ha3e maintained a per+ectly constant head pressure$ &his source o+ error could ha3e been miti"ated with a more comple. apparatus includin" a constantly runnin" water source and an o3erow route$ A second source o+ error was in the measurin" o+ the ow$ &he same "raduated cylinder was used +or each test without bein" completely dried between trials$ &his would ha3e led to inaccurate 3olume measurements$ A third source o+ error can li0ely be +ound in the limitations o+ measurin" the head di5erence with a human eye and a measurin" tape4 an imprecise combination$

D$ S)MMAF*  &he constant head permeability test e.periment success+ully yielded a 3alue +or the coe/cient o+ permeability$ ,owe3er4 this e.perimental 3alue4 ;$;181: cm9s was rather di5erent than the analytical 3alues determined by the Chaupis and )$S$ (epartment o+ %a3y methods4 ;$;11Bcm9s and ;$1 cm9s4 respecti3ely$ &he wide di5erence between the e.perimental and analytical 3alues su""ests that the possible sources o+ error mentioned in section #D o+ this report mani+ested themsel3es and a5ected the results$

Andrew Chapman – asc2172 Soil Mechanics - Wednesday Group ?Appendi. A@ (ate &ested*  &ested y* Soil (escription*

:9:91 Andrew Chapman Sand

#tem A3era"e Hlow4 E  &ime o+ Collection4 t  &emperature4 & ,ead (i5erence4 h Area o+ specimen4 A ermeability #tem A3era"e Hlow4 E  &ime o+ Collection4 t  &emperature4 & ,ead (i5erence4 h Area o+ specimen4 A ermeability #tem A3era"e Hlow4 E  &ime o+ Collection4 t  &emperature4 & ,ead (i5erence4 h Area o+ specimen4 A ermeability

(ry (ensity Doid atio 0

1$8IB 877 ;$7;:I8 :7 ;$;17 :71

&est 1-1

&est 1-2

&est 1-:

1: 12 I;$IB I;$2 2 2 12 12 28$I2;7BI 28$I2;7BI 22 22 ;$;2;2:I ;$;1;8B 2I II &est 2-1

&est 2-2

1; :;$;: 2 12 28$I2;7BI22 ;$;21;;82;: &est 2-:

1B 21 :$2 I;$; 2 2 22$ 22$ 28$I2;7BI 28$I2;7BI 22 22 ;$;11B 82 ;$;178278 &est :-1

&est :-2

2 27 :2$: :;$1I 2 2 :7 :7 28$I2;7BI 28$I2;7BI 22 22 ;$;178;B ;$;1:27I 7B 7

17 :2$7 2 22$ 28$I2;7BI22 ;$;17I8:1B &est :-: 27 :;$2 2 :7 28$I2;7BI22 ;$;17B2:117

Andrew Chapman – asc2172 Soil Mechanics - Wednesday Group 02; Chaupis 0 )$S$ %a3y 0

;$;181: ;I ;$;117 12: ;$1

?Appendi. @ 0 J EL9Aht 02; J 0 0chaupis J 2$I822<(1;2 >>$72