Predicting the undrained capacity of skirted spudcans under combined loading

To improve the moment fixity and increase the horizontal capacity of the shallow foundations for offshore structures, the spudcans are fitted with peripheral skirts and, often, internal skirts. The guidelines relevant to skirted spudcans acknowledge the increase in bearing capacity and in some cases, recommend solutions for embedded and skirted footings. In the current study, the undrained bearing capacity of the skirted spudcan foundation, on both homogeneous and heterogeneous soil, subjected to combined vertical (V), horizontal (H) and moment (M) loading is assessed by means of finite element analysis (FEA) and compared to known capacities for both conventional spudcans and circular skirted foundations. The improved capacity of the skirted spudcans to the conventional ones is evident and compares fairly with that of the skirted mats on homogeneous soil. Solutions for skirted spudcans on heterogeneous (normally consolidated) soil are also provided and interpreted.