Effects of spudcan installation processes on the bearing capacity of foundations under combined loading in soft-over-stiff clay

Abstract

The bearing capacity of spudcan foundations under vertical, horizontal, and moment loading must be adequately assessed prior to the operation of jack-up platforms. However, studies the effects of combined loading on spudcan foundations in soft-over-stiff clays, considering the effect of installation processes, have been limited. In this study, the two-dimensional remeshing and interpolation with small strain method was used to simulate the large deformations experienced by the soil during the installation of a spudcan, and a three-dimensional model was employed for the small strain analysis regarding the bearing capacity. The undrained shear strength of stiff clay influenced the failure mechanisms of the soil during vertical and moment loading. However, it had minimal impact during horizontal loading. Therefore, in this study, an equation for the bearing capacity factors for vertical and moment loading conditions is proposed. The properties and parameters of the combined bearing capacity failure envelope with respect to different dimensions are analysed and corresponding equations for the failure envelope are proposed, which aid the on-site assessment of jack-up platforms prior to them becoming operational.