A retaining wall .X m high was designed to stabilize a horizontal ground surface. The backof the wall is inclined 20° to vertical direction and can be assumed rough with interface \text { friction angle of } x^{\circ} \text {. The soil parameters are } \phi=33^{\circ}, \gamma_{\text {trulk }}=19 \mathrm{kN} / \mathrm{m}^{3}, \gamma_{s a f}=21 \mathrm{kN} / \mathrm{m}^{3} \text {. } Y csCSAssume no seepage effects. (a) Draw a diagram to show the given wall dimensions, relevant inclinations and thedirection of the active force on the wall. (2 marks) (b) Calculate lateral force on the wall assuming the ground water table is at theground surface. (5 marks) () After a flood, the ground water table rises 0.8 m above the wall top surface onboth sides of the wall. Calculate the lateral active force on the wall after theflood. (8 marks) (d) If the weight of the wall is (200+ X) kN/m, is the wall safe against sliding afterflooding event? Please show your calculations. (7 marks)