QUESTION $1(25$ marks$)$

A reinforced concrete wall is to retain two types of soils, viz. Loose Sand and Dense Sand, with the design cross$-$section and ground conditions as shown in Figure $1($a$).$ As the permanent groundwater table is well below the wall base, groundwater pressure shall be neglected in the design. The relevant material and design parameters are as follows:

$\backslash$table$[[$Loose Sand,$c^{\text{'}}=0$;${}^{\text{'}}=30$; Density, $=20k\frac{N}{m^3}$