Response of Cross‐Anisotropic Seabed to Ocean Waves

Abstract

Quasi‐static field equations for fully saturated porous elastic media, based on Biot's theory (1972‐1973), established in the writer's previous works (1989‐1990) are used in order to describe the behavior of such materials under wave ocean loading. A brief description of cross anisotropy with a vertical axis of symmetry (orthotropy) is given. The five independent elastic parameters of anisotropic materials are clarified. The field equations are modified and adapted for application to anistropic cases. A numerical procedure (finite element discretization) for the motion equations of an orthotropic saturated poro‐elastic seabeds is presented. The accuracy of the chosen algorithm is discussed. The wave‐induced pore pressures, effective stresses and displacements in an anisotropic submarine sediment are investigated. The results illustrate a significant influence of elastic anisotropic parameters on the wave‐induced pore pressures, effective normal stresses, shear stresses, horizontal and vertical displacements at the bed surface and in depth. A parametric study is performed in order to clarify the effect of the orthotropic constants for a sandy soil. The response of an isotropic seabed with a finite thickness to a harmonic wave loading is compared with an orthotropic case.