Dynamic Response of Multilayered Silty Seabeds under Wave-Current Action in the Yellow River Estuary

Abstract

Few studies have focused on pore pressure and liquefaction in a layered silty seabed. This study investigated a silty seabed in the Yellow River Estuary. Based on Biot’s theory and further considering the influence of current, a numerical validation of two-dimensional seabeds under combined wave and current action was established with a quasi-static model. Based on this model, the dynamic response of five typical layered seabeds was explored under combined wave and current actions. The numerical results demonstrate a significant discrepancy in dynamic response. For instance, the distribution of the pore pressure versus the soil depth was found to be entirely different, especially for Seabed 1 and Seabed 4 (S1 and S4), where two peak values of the pore pressure occurred. Furthermore, considering the residual pore-pressure term in the liquefaction analysis, the liquefaction formed fastest in Seabed 5 (S5), and the maximum accumulative liquefaction depth was the greatest for Seabed 1 (S1), at slightly more than 8.5 m. In addition, the influences of waves and currents on the dynamic response of seabeds are discussed in parametric study, which indicates that waves and currents have a significant effect on the pore-pressure distribution. The relative differences in the maximum pore pressure for different currents, wave heights, and wave periods were found to be 27.8, 24.9, and 22.4%, respectively, of the maximum linear wave pressure P in Seabed 2 (S2).