Civil Engineering - Soil Mechanics and Foundation Engineering - Discussion

13.5 will be the correct answer.

a = (60-35) = 25
b = (60-15) = 45 is not more than 40 so let b = 40.
c = (65-40) = 25 is not more than 20 so let c = 20.
d= (60-15) = 45 is not more than 40 so let d = 40.

Calc.,
G.I = (0.2x25)+(0.005x25x20)+(0.01x40x20)
= 15.5.

15.5 will be the correct answer.

13.5 is correct answer.

Given:- % passing (P) =60%, LL = 65%, PL = 40%.

We have GI = 0.2a+0.005ac+0.01bd.

To get a,b,c and d value, we need Percentage passing 75 micron IS sieve, Liquid Limit and Plasticity Index.

So Plasticity index = LL - PL = 65-40= 25.
Now a= 60-35=25 (value is 0-40),
b =60-15 =45 (value >40, so take 40),
c= 65-40=25 (value > 20, so take 20),
d = 25-10=15 (value between 0 to 20),
Now GI= 0.2 x 25 + 0.005 x 25 x 20 + 0.01 x 40 x 15 = 13.5.

So the answer is D.

Correct @Pritam Yadav.

a & b should not be greater than 40.
c & d should not be greater than 20.

I think b value is zero as b is the percentage of soil passing through 0.074 mm sieve in excess of 15%, not exceeding 55%. But given here as 60% which is greater than 55%. So, I think b=0.

The answer will be 14.875..so, The option none of these is the correct one.

GI= 0.2a+0.005ac+0.01bd.
a= % of soil passing through 0.075 sieve - 35.
b= % of soil passing through 0.075 sieve - 15.
c= Liquid limit - 40,
d= plasticity index - 10,
Plasticity index= Liquid limit - Plastic limit.

A is the correct answer guys.

0.2a+0.01ad+0.005ac.

a = %particle passing through 75micron sieve and their given % should be lie between (35<a>75) means whose value ranges from (0-40) in this question given value is 60% which means (a=60-35=25).

b=%particle passing through 75-micron sieve and lies between (15<b>55) which means (0-40) but in this question which is 60 % so it is not full fill our condition so b=0.

c = liquid limit lies between (40<c>60) which lies on range (0-20) in this question which is 65% so,

c = 0
d = plasticity index lies between (10<d>30) on range (0-20) in this question which is P.I = 65-40=25.

So, its range is d = 25 - 10 = 15.
d = 15.

Summary
a=25
b=0
c=0
d=15

G.I = 0.2a + 0.01bd + 0.005ac.
= 0.2 * 25+0.01 * 0 * 15 + 0.005 * 25 * 0.
= 5.0 + 0 + 0
G.I = 5.0.
So, A is the correct answer.

A=60-35=25 (0 to 40),
B=60-15=45 (0 to 40) = 40,
C=65-40=25 (0 to 20) =20,
Ip=65-40=25.

D=25-10=15 (0 to 20),
G.I = 0.2*a + 0.01*b*d +0.005*a*c.
= 0.2 * 25 + 0.01 * 40 * 15 + 0.005 * 25 * 20.
= 13.5.

So, here, option D is correct.

GI = .2 * a +.005* a*c +.01*b*d.

a = P (% passing from 75-micron sieve ) - 40 (value not more than 40.. if more than 40 then take 40).

a= 60-35= 25 ok not more than 40.
b= P (% passing from 75 micron sieve ) - 15 (value not more than 40.. if more than 40 then take 40),
b= 60 - 15 =45 ( not ok ) (take 40).

c= wL (liquid limit ) -40 (value not more than 20.. if more than 20 then take 20),
c= 65- 40 = 25 (not ok ) ( take 20).

d= IP ( plasiticity index ) - 10,
d=( WL liquid limit( 65) - (40)WP plastic limit )- 10,
= 25-10 = 15 ok value less than 20.

So , G.I = .2*25 +.005*25 * 25 + .01*40 * 15,
and 14.125 is the correct answer.