Q1: The compression index of a soil

ANS:B - increases with an increase in the liquid limit

Cc= 0.009(LL-10) ; for undisturbed soil of medium sensitivity.
Cc= 0.007 (LL-7) ; for remoulded soil of low sensitivity.
Cc= 0.4(e-0.25); for undisturbed soil of medium sensitivity, where e= initial void ratio. Cc = 0.009(LL-10) for undisturbed clays.

Cc = 0.007(LL-10) for remolded Clays.

There are many other correlations for Compression Index which involve the in-situ void ratio, and in situ water content. Compression index describes variation of void ratio as a function of the change of effective stress plotted in the logarithmic scale.

It therefore represents deformative characteristics of overconsolidated soil.

Typical range of compression index is 0.1 to 10.