Q$.3$ Plot the distribution of active pressure on the wall surface as shown. The surcharge on the wall is $7k\frac{N}{m^2}.$ Calculate the total thrust on the wall $($active and hydrostatic$)$ and determine its point of application. Above the water table the unit weight of the retained soil is $18k\frac{N}{m^3}$ and below the water table the saturated unit weight is $20kN/$ Let $c^{\text{'}}=0k\frac{N}{m^2},{}^{\text{'}}=35.$

$(20\%)$