A Note on Bearing Capacity of Soft Clays under Embankments

Abstract

This paper presents a rigorous lower‐bound solution for the bearing capacity of soft clays under embankments. The analysis is carried out by using a numerical technique that is based on the lower‐bound theorem and finite elements. It is found that the lower‐bound solution obtained in this paper agrees well with the upper‐bound solutions obtained from Hill and/or Prandtl failure mechanisms. The lower‐bound solution for the vertical stresses that a soft foundation can support in combination with a surface shear stress (or shear force) can be used to obtain a safe design for the critical heights of both unreinforced and reinforced embankments by following an iterative procedure similar to that described by Michalowski in 1992. The usual assumption of a uniform shear stress mobilization underneath the embankment is shown to be conservative as it leads to a slightly lower value of the vertical bearing capacity.