Numerical Modeling of the Dynamic Response of an Elastoplastic Seabed Under Wave-Current Interactions

Wave-induced liquefaction of the seabed is a geohazard frequently encountered in shallow waters. Although widely discussed, most studies paid attention to the seabed response under a single sequence of wave loading. However, the seabed suffers from repeated ‘wave loading-dissipation’ phases in a real ocean environment. In this study, a homogeneous sandy seabed model is established to investigate the mechanism of wave-induced liquefaction by considering the existence of currents. Finite element analyses are conducted by incorporating a kinematic hardening elastoplastic model into the commercial package Abaqus. The constitutive model is validated against centrifugal wave tests. Parametric studies are conducted to demonstrate the effects of relative densities, current, and wave-loading history on the seabed response. The predicted excess pore pressure, effective stress paths, and associated variation of relative density are discussed in detail. The results show that the densification of soils significantly enhances the resistance against liquefaction, which provides new insight into the mechanism of residual liquefaction during wave sequences.