Question

A uniform sand stratum 2.5 m thick has a specific gravity of 2.62 and a natural void ratio of 0.62. The hydraulic head required to cause quick sand condition in the sand stratum is

• A. 0.5 m
• B. 1.5 m
• C. 2.5 m
• D. 3.5 m

Answer 1

The correct option is C 2.5 m

Critical hydraulic gradient,

$i_c=\frac{G-1}{1+e}=\frac{2.62-1}{1+0.62}=1.0$

Head required

$=i_c\times thicknessofsand$

$=1\times 2.5=2.5m$