Question $2.(24$ marks$)$

A Building shown in the figure below is subjected to a loading of $100$kPa.

Determine the vertical stress increase at a depth $z=3m$ below the base of

the foundation under point $B$ :

$($i$)$ using $m$ and $n$ coefficient method, and

$($ii$)$ using the Newmark's method,

$($iii$)$ what are the advantages and disadvantages of these two methods?