foundation pressure

Problem 911
A concrete dam has the profile shown in Figure P-911. If the density of concrete is 2400 kg/m³ and that of water is 1000 kg/m³, determine the maximum compressive stress at section m-n if the depth of the water behind the dam is h = 15 m.
 

Dams are structures whose purpose is to raise the water level on the upstream side of river, stream, or other waterway. The rising water will cause hydrostatic force which will tend the dam to slide horizontally and overturn about its downstream edge or toe. The raised water level on the upstream edge or heel will also cause the water to seep under the dam. The pressure due to this seepage is commonly called hydrostatic uplift and will reduce the stability of the dam against sliding and against overturning.
 

Problem 353
The forces acting on a 1-m length of a dam are shown in Fig. P-353. The upward ground reaction varies uniformly from an intensity of p₁ kN/m to p₂ kN/m at B. Determine p1 and p2 and also the horizontal resistance to sliding.