Question

The particle size distribution of a soil sample shows that 30 percent of soil particles pass from 75$\mu$ sieve. The liquid limit and plastic index of fine portion are 36 and 15 respectively. The group index of soil is_____

• A. 1

Answer 1

The correct option is A 1
GI=0.2a + 0.005ac + 0.01 bd

a= portion of percentage passing 75$\mu$ sieve greater than 35=0

b= portion of percentage passing 75$\mu$ sieve greater than 15=30-15=15

c=portion of LL greater than 40 and not exceeding 60=0

d= portion of PI greater than 10, not exceeding 30=15-10=5.

$GI=0.2\times \left(0\right)+0.005\times \left(0\right)\left(0\right)+0.01\times 15\times 5=0.75\simeq 1$