Civil Engineering - Soil Mechanics and Foundation Engineering - Discussion

GI= { 0. 2 a + 0. 005 ac + 0. 01 bd } ------> eq. (1).

A = % of soil passing through 0. 075 sieve - 35. {limit 1 < a < 40}.
A = 60 - 35 = 25 (ok within limit).

B = % of soil passing through 0. 075 sieve - 15. {limit 1 < b < 40}.
B = 60 - 15 = 45 (It's over limit) so we will take = 40.

C = Liquid limit - 40. {limit 1 < c < 20}.
C = 65 - 40 = 25 (It's over limit) so we will take = 20.

D = plasticity index - 10. {limit 1 < d < 20}.
{Plasticity index = Liquid limit - Plastic limit}.
D = (65 - 40) - 10 = 15 (ok within limit).

Putting the value of a, b, c, d in eq. (1).

GI = 0. 2 a + 0. 005 ac + 0. 01 bd.
GI = (0. 2 x 25) + (0. 005 x 25 x 20) + (0. 01 x 40 x 15).
GI = 13. 5.
So, The answer will be 13. 5.
And None of these is the correct one.

Right @Pkota.

I too agree, the answer is 13.5.

You are right, thanks @Gaurav Sharma.

The Ans will be 13.5.

No @All.

The group index should be rounded to nearest whole number suppose GI = 14.125 it should be rounded off to 14.

The correct answer is 13.5.

Yes, the correct Answer 13.5.

The correct answer is option D. Agree with the given answer.

GI = .2a +.005ac +.01bd.

a = 25,
b = 45, bt not more than 40, = 40,
c = 25, bt nt more thn 20, = 20,
d = 15,
GI = .2 * 25 +.005 * 25 * 20 +.01 * 40 * 15 = 13.5.

13.5 is the correct answer of this question.