Based on the Biot consolidation theory and the two layer ocean diffracted wave theory

the wave seepage forces on vertical porous circular annular cylinder resting on porous elastic seabed in two layer ocean has been investigated by applying the eigenfunction expansion approach. The analytical solutions to seepage pressure fields caused by surface wave and inner wave are given respectively and then the wave-induced lift force and overturn moment caused by the seepage pressure on the bottom of vertical porous circular annular cylinder are evaluated. The results demonstrate that the porosity of the external surface of the cylinder will lead an obvious reduction in direct wave loads on cylinder and certain reduction in seepage overturn moment on the bottom of cylinder. Inner wave-induced seepage overturn moment may be greater than that induced by surface wave. Decreasing the ratio of the cylinder's inside diameter to outside diameter will lead more obvious diminishing effect of direct wave moment than that of wave-induced overturn moment.