Hydropower Engineering past question

A concrete gravity dam (trapezoidal in section) has height 20 m, top width 1.2 m and bottom width 10 m is proposed to block the water of height 18 m. The u/s face of the dam is vertical and the d/s face has slope 1:2 (H:V). Considering the forces: self weight, hydrostatic force and uplift pressure, check the stability of the dam. (Assume unit weight of concrete=24 KN/m³, permissible shear stress of joint as 1400 KN/m², coefficient of friction as 0.75, and uplift factor k as 0.8). Neglect the tail water effect to the dam. [8]