QUESTION $3,(25$ marks$)$

A sheet$-$pile wall is to be provided at a site comprising Sand, with $5$ m retained height while the retained ground is dipping downward at $10$ from the horizontal as shown in Figure $3($a$).$ Groundwater pressure and the weight of the sheet$-$pile wall shall be neglected in the design. The unfactored material and design parameters are as follows:

$\backslash$table$[[$Sand$,c^{\text{'}}=0$;${}^{\text{'}}=35$; Density, $=20k\frac{N}{m^3}$