A Semi-Dynamic Coupled Model of Seabed Oscillatory and Residual Response Under Wave-Current Interaction

The evaluation of the wave-induced residual pore pressure in a porous seabed is vital for the prediction of the potential of seabed instability under the combined action of waves and currents. Based on the Biot’s quasi-static consolidation model, previous studies have typically used decoupled models to separately discuss oscillatory pore pressure and cumulated pore pressure, which ignores the inertia effects due to the acceleration of solid particles on the accumulation of pore pressure. In this paper, considering coupling effect between oscillatory and accumulated pore pressures, a semi-dynamic coupled model for soil dynamic response under wave-current interaction is proposed. Upon comparison with existing laboratory experimental data, the capacity of the proposed coupled method is demonstrated. A series of parametric studies were conducted to analyze the influence of wave characteristics and soil parameters on cumulative pore pressure and corresponding liquefaction. The results indicate that changes in wave height, water depth, and relative density significantly affect the accumulation pore pressure and the development of the maximum liquefaction depth. The difference in maximum liquefaction depth predicted by the semi-dynamic coupled model and the quasi-static coupled model is within 6%, indicating the influence of soil particle acceleration on pore pressure accumulation.