ABSTRACT
Majority of previous model for the wave-induced oscillatory seabed response have been limited to homogeneous seabeds with constant permeability even a few researchers made attempts to further consider layered seabed, cross-anisotropic seabed, variable permeability and shear modulus etc. Such simplifications in models pose some problems such as non-physical tensile stress in the non-cohesive liquefied zone. In this chapter, two models are proposed for two special cases for ocean waves over a porous seabed: a penalty-like dynamic permeability model for a non-cohesive seabed with dynamic permeability as a function of pore pressure and a non-Darcy flow model for the wave-induced instantaneous liquefaction in a non-cohesive seabed. The proposed dynamic permeability model can alleviate or even eliminate the non-physical tensile stress in the liquefied zone and obtain a better agreement with existing cylinder tests under 1D wave loading. It is also found that the conventional constant permeability model overestimates the liquefaction potential comparing with the dynamic permeability model. In addition, using the non-Darcy flow model, the predicted liquefaction depth is roughly 0.73 times of the value predicted by the conventional model.
