Partial dynamic (u−p) integrated model for both oscillatory and residual soil response in a poro-elastic seabed

The evaluation of pore pressures and its associate seabed liquefaction under hydrodynamic loading in marine environments is particularly important for the design of foundation of marine infrastructures. Most existing poro-elastic seabed models considered either oscillatory or residual mechanisms individually, rather than integrating both mechanisms, although they may be equally important under specific conditions. Furthermore, the existing poro-elastic models for residual soil response were limited to quasi-static (QS) approach. In this paper, a new poro-elastic model for residual mechanism is first developed by considering the acceleration of soil particles. Then, both oscillatory and residual seabed response under combined wave and current loading will be integrated. An index, the ratio of equilibrium residual pore pressure to amplitude of oscillatory pore pressure, is proposed to clarify the ranges of the dominant mechanism. The parametric study suggested the nonlinear correlation between relative wave height and relative water depth. Finally, the present study investigates the maximum liquefaction depth under combined wave and current loading and compares with the conventional QS decoupled model.