Q$1-$ A retaining wall $6\mathrm{.}0$ m high retains a cohesive soil with inclined ground surface making an

angle of $15$ with the horizontal. The soil has cohesion of $16k\frac{N}{m^2},$ angle of internal friction of

$27$ and unit weight of $19\mathrm{.}8k\frac{N}{m^3}.$ The failure wedge is making angle of $55$ with the horizontal

and a surcharge load of $40k\frac{N}{m^2}$ is subjected to G$.$S$.$ Determine the active earth thrust against the

wall. Use $.$ Show all required sketches with clear labels.