Question

While boring was being done, the soil sample was found to be saturated with kerosene oil. The saturated unit weight of soil was found to be 2.5 gm/cc. If the specific gravity of soil grains and kerosene oil be 2.7 and 0.9 respectively, the dry unit weight is..... g/cc

• A. 2.4
• B. 1.8
• C. 1.6
• D. 2.6

Answer 1

The correct option is A 2.4

Given :

Soil is saturated with kerosene oil
$\therefore {\gamma }_{sat}=2.5gm/cc$

$G=2.7$

$S_o=0.9$

${\gamma }_{sat}=\left(\frac{G+e.S_r.S_o}{1+e}\right){\gamma }_w$

$2.5=\left(\frac{2.7+e\times 1\times 0.9}{1+e}\right)\times 1$

$2.5+2.5e=2.7+0.9\times e$

$\therefore e=0.125$

${\gamma }_d=\frac{G{\gamma }_w}{1+e}$

${\gamma }_d=\frac{2.7\times 1}{1+0.125}$

${\gamma }_d=2.4g/cc$