Numerical modeling of skirted foundation in alternating layers of sand and clay

Abstract

Estimation of bearing capacity is critical in the design of skirted foundations. Empirical formula and closed form solutions for skirted foundations in uniform profiles composed of sand or clay have been proposed. However, the capacity of foundations in alternating layers of sand and clay is not well defined. We perform a series of three-dimensional elasto-plastic finite element analyses on such profiles and calculate the bearing capacity of skirted foundations. It is shown that assuming a uniform profile is not appropriate. Even a thin layer of clay below the tip of the skirted foundation can significantly reduce the capacity of the foundation. We present predictive equations and charts for determining the vertical bearing capacities of foundations in heterogeneous profiles.