Numerical Modelling of Pore Pressure Accumulations in Marine Sediments around Submerged Breakwaters under Combined Wave and Current Loadings

Abstract

In this study, an integrated model for the wave (current)-induced seabed response around submerged breakwaters is proposed. The Reynolds-Averaged Navier-Stokes (RANS) equations and k − ε turbulence model were used for the flow field, whereas an inelastic two-dimensional seabed model was used for pore pressure accumulation in a porous seabed. Unlike previous studies, the residual soil response was considered in the present model, together with the interaction between waves and currents and the preconsolidation process. The present model was validated with previous studies for wave–current interaction model and seabed models. Based on the numerical examples presented, the following conclusions were made: (1) preconsolidation because of static loading of breakwaters and static water pressures significantly affects the seabed response around the breakwaters, (2) the liquefaction depth under combined wave and current loading is less than that under wave-only loading, (3) the maximum liquefaction depth increases as the width and height of the submerged breakwater increase, and (4) liquefaction depth for the submerged, multiple breakwaters is smaller than that for a single, submerged breakwater.