Wave-induced dynamic response in a transversely isotropic and multilayered poroelastic seabed

Abstract

The dynamic response of a transversely isotropic, multilayered and poroelastic seabed under the action of two-dimensional water waves is investigated via a recently developed semi-analytical method. The coupled governing equations of motion are based on the Biot's complete poroelastodynamic model, expressed in the (u,p) form. The potential-function method is introduced to express the unknown primary quantities such that the general solution in each layer is obtained with six undetermined coefficients. By virtue of the stable and efficient dual variable and position method, a general recursive relation for the displacements, stresses and pore pressure among different layers is established. The semi-analytical solutions for the layered seabed with two typical bottom boundary conditions are derived. Particularly, for the homogeneous transversely isotropic seabed, exact solutions are also derived for different bottom boundaries. The accuracy and reliability of the solutions are verified against existing solutions. Selected numerical examples are further presented to study the effect of anisotropic stiffness, anisotropic permeability and material layering on the wave-induced pore pressure and effective stresses.