Bearing Performance of Finned Suction Caissons under Combined VHMT Loading in Clay

This paper reports numerical investigations on the bearing performance of a novel finned suction caisson foundation under combined vertical, horizontal, moment, and torsional loading in clay. From comprehensive comparison analyses between finned and nonfinned suction foundations, improvements in uniaxial and combined loading capacities due to the assembled fins are examined and interpreted by insights into the failure mechanisms. Effects of non-coplanar torsional loading on the combined loading capacity surfaces are investigated and evaluated with the aid of the failure envelope method. A set of closed-form expressions accommodated to three different loading scenarios (zero-, low- and high-torsion conditions) are proposed based on a detailed design chart to estimate the bearing performance under combined vertical (V), horizontal (H), moment (M), and torsional (T) loading (denoted as VHMT loading) in clay. The critical considerations in design including effects of loading direction and foundation–soil interface are also discussed.