Integrated Model for Wave-Induced Oscillatory and Residual Soil Response in a Poro-Elastic Seabed: Partially Dynamic Model

Abstract

The evaluation of wave-induced residual pore pressure in a porous seabed and associated seabed liquefaction is essential for designing marine infrastructure foundations. The strength and stiffness of the seabed could be weakened due to the build-up of pore pressures under cyclic wave action, further leading to residual liquefaction. Existing models for residual liquefaction are limited to the quasi-static uncoupled approaches, which do not account for the effect of oscillatory pore pressure on the accumulative pore pressure acceleration of solid particles, despite the mutual influence of these two mechanisms. To overcome these limitations, this paper proposes a new model for residual soil response with u−p approximation (partial dynamic model) that couples oscillatory and residual mechanisms. The proposed model is validated through wave flume tests and centrifuge tests. Based on the coupling model, a new criterion of liquefaction integrating both oscillatory and residual mechanisms is also proposed. Numerical examples demonstrate that the coupling effect significantly affects the wave-induced seabed liquefaction potential. Furthermore, a new parameter (Ω) representing the ratio of oscillatory and residual pore pressure is introduced to clarify which mechanism dominates the pore pressure development.