Wave Interaction with a Porous Structure over a Sandy Seabed (No. R862)

Abstract

In this study, a new analytic solution of the wave interaction with a porous structure over a sandy seabed is derived. A uniform water depth is assumed, and the layer of the rigid porous medium is placed over an infinite thickness of poro-elastic sand bottom. The potential theory with the inertial and damping effects in the porous flow is considered in the rigid porous region, while the soil consolidation theory is adopted in the sand region. A new complex dispersion relationship involving the parameters of the rigid porous and poro-elastic medium is obtained. The analytic solutions can be simplified to the special cases, such as the wave interaction with the porous structure over an impermeable bottom or only interaction with the poro-elastic medium. The results indicate that the wave decay is highly dependent upon the thickness of the porous structure, the soil stiffness and their permeability. The increase of the thickness of the porous structure will shorten the wave length of the surface waves regardless of the coarse or fine sand. The pore pressure of the fine sand is larger than that of coarse sand, both decay with the distance of the wave progressing. It is also found that the increase of the thickness of the porous structure will effectively reduce the pore pressure in the sand.