In this paper, a three-dimensional porous model for wave-seabedstructure interactions (PORO-WSSI-3D) will be developed by integrating 3D wave and seabed models. Unlike previous research, the Navier-Stokes equation is solved with internal wave generation for the flow model, while Biot's dynamic seabed behavior is considered in the seabed model. With the newly developed 3D model, the wave-seabed interactions around breakwater heads are used as numerical example. Numerical results demonstrate the capacity of the proposed numerical model. The parametric study illustrates the significant influence of wave and soil characteristics on the pore pressure in a porous seabed.


Breakwaters have been widely used as one of coastal defense structures in the world. The design of breakwaters has attracted great attentions from coastal engineers. Recently, it has been reported that numerous marine structures have been vulnerable to liquefaction of the foundation seabed, which further leads to the degradation of their structure and function in as little as a few years, and often results in collapse of marine structures (Lundgren et al., 1989; Franco, 1994; Chung et al., 2006). It has been well known that when ocean waves propagated over the ocean surface, they exert dynamic force fluctuations on the sea floor. These fluctuations further generate excess pore pressure within the soil skeleton, which is a major factor in the seabed instability. Recently, numerous investigations for the wave-induced oscillatory soil response have been carried out since the 1970s. Among these, Yamamoto et al. (1978) proposed an analytical solution of the wave-induced oscillatory soil response in an infinite seabed. Regarding the mechanism of pore pressure build-up, Sumer and Cheng (1999) developed an analytical solution with the periodic shear stress obtained from Hsu and Jeng (1994), which has been first published in the book written by Sumer and Fredsøe (2002).

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