Example $6\mathrm{.}3$: A glass container with pervious bottom containing fine sand in loose state $($void

ratio $=0\mathrm{.}8)$ is subjected to hydrostatic pressure from underneath until quick condition occurs

in the sand. If the specific gravity of sand particles $=2\mathrm{.}65,$ area of cross$-$section of sand sample

$=10c{m}^2$ and height of sample $=10cm,$ compute the head of water required to cause quicksand

condition and also the seepage force acting from below.