Question

The result of a consolidation test on an undisturbed soil, sampled at a depth of 10 m below the ground level are as follows:

Saturated unit weight : 16 kN/$m^3$

Pre-consolidation pressure : 90 kPa

The water table was encountered at the ground level. Assuming the unit weight of water as $10kN/m^3$, the over-consolidation ratio of the soil is

• A. 0.67
• B. 1.50
• C. 1.77
• D. 2.00

Answer 1

The correct option is B 1.50


$\overline{\sigma }={\gamma }_{sub}\times 10$

= (16 - 10) $\times$ 10

$\overline{\sigma }=60kN/m^2$

$\Rightarrow OCR=\frac{{\sigma }_c}{\overline{\sigma }}=\frac{90}{60}=1.5$