Analysis of unreinforced and reinforced embankments on soft clays by plasticity theory

The design of both unreinforced and reinforced embankments on soft clay is dominated by the clay strength, and can be treated as a bearing capacity problem. As well as exerting vertical stresses on the clay surface, unreinforced embankments exert outward shear stresses which result in a reduction of the bearing capacity factor. In reinforced embankments these shear stresses are carried by the reinforcement, and only vertical load is transferred to the clay below. For the important case of an embankment on a soil with an increasing strength with depth a futher benefit is gained due to inward shear stresses on the clay surface. Solutions from plasticity theory are presented which are of direct application to the design of embankments.