Three-dimensional finite element analysis of combined loading of skirted foundations on non-homogeneous clay

Combined loading of shallow foundations is particularly relevant in offshore engineering as wind and wave loading cause significant lateral and moment forces to the foundations of offshore structures. Research to date has addressed either combined loading of strip footings on non-homogeneous soils (e.g. Bransby & Randolph, 1998) or of circular footings on homogeneous soils (e.g. Taiebat & Carter, 2000). The present paper contributes towards this database by presenting the results of three-dimensional finite element analyses, which have addressed the issues of combined loading, soil strength non-homogeneity and three-dimensional foundation geometry integrated in single analyses. Attention is focused on the effect of the degree of strength non homogeneity on the size and shape of the failure loci under combined vertical, moment and horizontal loading.