Question

The compression curve (void ratio, e vs, effective stress, ${\sigma }_v^{\prime })$ for a certain clayey soil is a straight line in a semi-logarithmic plot and it passes through the points (e = 1.2; ${\sigma }_v^{\prime }=50kPa)$ and (e = 0.6; ${\sigma }_v^{\prime }=800kPa)$. The compression index (up to two decimal places) of the soil is

• A. 0.5

Answer 1

The correct option is A 0.5
Compression index

$C_c=\frac{\Delta e}{log\left({\overline{\sigma }}_2/{\overline{\sigma }}_1\right)}$

$=\frac{1.2-0.6}{log\left(\frac{800}{50}\right)}$

$=\frac{0.6}{log\left(16\right)}=0.50$