Question

Data from a sieve analysis conducted on a given sample of soil showed that 67% of the particles passed through 75 micron IS seive. The liquid limit and plastic limit of the finer fraction was found to be 45 and 33 percent respectively. The group symbol of the given soil as per IS:1498-1970 is

• A. SC
• B. MI
• C. CH
• D. MH

Answer 1

The correct option is B MI

Fineness > 12%

$I_p=0.73(W_L-20)$

= 0.73 (45 - 20) = 18.25

$I_p=W_L-W_P$

= 45 - 33 = 12%

Hence point is plotted below the Atterberg's line and 35 < $W_L$ < 50.

$\therefore$ Group symbol is MI.