The rectangular retaining wall has a height H, a width

The rectangular retaining wall has a height H, a width b (Fig. 1), and masonry density ρcl.
Water depth in front of the wall h, water density ρв = 1000 kg / m3; gravitational acceleration g = 9.81 m / s2.
Given: H = 3.5m; b = 0.9m; ρcl. = 2150 kg / m3; h = 2.7m
It is required to determine:
1. The force of excess hydrostatic pressure per 1 meter of wall length, having previously built a diagram of hydrostatic pressure.
2. The position of the center of pressure.
3. The margin of stability K of the retaining wall overturning.
4. The width of the wall b3 with a safety margin of K = 3.