Gravity wharf failure mechanism and safety analysis considering the wave-structure-soft-soil-foundation interaction

Abstract

The soft soil foundations of gravity wharves are subject to the wharf weight and wave forces, and the deterioration of the wharf soil foundation strength under such cyclic loading affects the structural safety of gravity wharves. This study investigated the weakening characteristics of soft soil strength. Undrained triaxial tests were conducted on undisturbed saturated soft soil specimens under isotropic consolidation conditions, and a dynamic finite element model of the wave–gravity-structure–soft-soil-foundation interaction was established. The results indicated that the shear modulus of the soil was related to the effective confining pressure and shear strain; this relationship was fitted using the Van Genuchten equation. As the internal friction angle of the soft-soil foundation decreased, its stability decreased nonlinearly, the strength decreased, and the sliding failure surface expanded. Simply increasing the riprap layer thickness had a limited effect on the overall wharf stability. These findings will guide the design of gravity wharves with foundations on soft soils in port areas that are subjected to intense wave actions.