Boundary-Layer Theory for Anisotropic Seabed Response to Sea Waves

Abstract

By employing a boundary-layer concept, the wave-induced fluctuation of pore-water pressure in an anisotropic seabed of semi-infinite depth is derived in a simple form, which contains the solution of the isotropic case. The solution of pore-water pressure consists of the two exponential terms with the different decay rates, and it is characterized by two factors: The boundary-layer thickness and weights of the two terms. The boundary-layer approximation shows that the two factors are dominated by two dimensionless parameters: One is a kind of Terzaghi's consolidation coefficient represented by properties of waves and soil, and the other is the stiffness ratio related to the saturation of pore water. These two factors can be expressed simply by modifying those of the isotropic case.