Q$3.$ A $500$ KN load is to be supported on a $3m3m$ footing, embedded $1\mathrm{.}5$ m below the ground surface. The soil below is a well$-$graded, normally consolidated sand with $=16\mathrm{.}0k\frac{N}{m^3}$ an $m=21k\frac{N}{m^3},$ and the following SPT $N_{60}$ values.

$\backslash$table$[[$Depth $($m$),1\mathrm{.}5-2,2-4,4-6,6-12$