An Examination of the Failure Envelope of Finned Suction Anchors Subjected to Combined Vertical–Horizontal Loadings in Clay Through Numerical Modeling

The addition of fins to suction anchors has been proposed to enhance bearing capacity in combined loadings. This study examines the failure envelope of finned suction anchors subjected to combined vertical–horizontal loadings in normally and lightly over-consolidated clay using the finite element method, focusing on fin capacity enhancement and fin efficiency against penetration resistance. Parameters considered include different length-to-diameter ratios of the suction anchor, as well as different fin-to-shaft-length ratios, to evaluate the effect on capacity. The addition of fins expands the vertical–horizontal failure envelope, minimally altering the shape of the failure envelope. The fin factor (the ratio of the finned suction anchor capacity to the conventional suction anchor capacity) increases with fin lengths but exhibits minimal dependence on length-to-diameter ratios. A nonlinear relationship between fin length and fin factor (both vertical and horizontal) with a distinct trend is observed in horizontal capacity. Fin efficiency (the ratio of capacity to penetration resistance) decreases with increasing fin length except at a fin length-to-shaft ratio of unity in horizontal capacity.