Dynamic response of porous seabed to ocean waves

Abstract

In this paper, dynamic response of a seabed to ocean waves is treated analytically on the basis of a poro-elastic theory. The seabed is modelled as an isotropic homogeneous material of finite thickness. Most previous investigations for the wave-seabed interaction problem have treated the problem in the well-known quasi-static state. However, the dynamic response of the porous seabed cannot be predicted in the quasi-static solutions, because the acceleration generated by pore fluid and soil particles are excluded in the previous solutions. This paper proposes a semi-analytical solution for the dynamic response of seabed to waves. Based on the newly solution, the relative differences between dynamic and quasi-static solutions and the wave driven seepage flux at the water-sediment interface will be examined. The wave-induced pore fluid displacement is about ten times of soil displacements in gravelled seabed. The wave driven seepage flux is important in a coarser unsaturated seabed of thicker thickness under the action of a longer wave in shallow water.