Porous structures have the property of diminishing wave loads. Based on first order cnoidal wave theory and Biot consolidation theory

the mathematical solutions are derived for shallow water wave diffracted pressure and waveinduced seepage pressure on a porous vertical circular cylinder resting on porous elastic seabed in shallow water

and direct wave force and moment and waveinduced uplift force and overturn moment on the circular cylinder are correspondingly evaluated. The result shows that the variation of ocean condition and structure parameter have different effects on various wave loads， the magnitude of wave-induced seepage loads may have same order of horizontal wave loads

and the permeability of the cylinder surface will lead an obvious reduction in direct wave effects on cylinder and certain reduction in seepage overturn moment on the bottom of cylinder. Furthermore

the suitable choice of the ratio of the cylinders inside diameter to outside diameter may lead effects of both diminishing wave loads and ensuring stability of circular cylinder. Compared with the results from Airy wave theory

the wave load prediction values from shallow water wave theories can reflect wave nonlinearity effects.