A smooth backed vertical wall is 6.3 m high and retains a soil with a bulk unit weight of 18 kN/m3 and φ = 18°. The top of the soil is level with the top of the wall and is horizontal. If the soil surface carries a uniformly distributed load of 4.5 kN/m2, verify the total active thrust on the wall per lineal metre of the wall and its point of application