Semi-analytical solutions for the wave-induced and vertical earthquake-induced responses of a fluid-stratified seabed-bedrock system

Ocean site can be modeled as a fluid-seabed-bedrock system, in which the seabed is horizontally layered poroelastic medium and the bedrock is a solid medium. The estimation of the wave-induced and earthquake-induced responses of the seabed played an important role in the design of offshore structures, which has attracted the attention of researchers and engineers. Based on Biot's poro-elastic theory, semi-analytical solutions are derived to evaluate the wave-induced and vertical earthquake-induced responses of the fluid-stratified seabed-bedrock (FSSB) system. The solutions for the wave-induced and vertical earthquake-induced responses of the fluid medium, the poro-elastic medium, and the solid medium are first derived. Then, the transfer matrix is obtained by applying the continuous conditions between the interfaces of the stratified seabed. Finally, a new wave dispersion equation for waves propagating over the FSSB system and the analytical solution for the wave-induced and vertical earthquake-induced responses of the FSSB system are established by using boundary conditions. Based on the present solution, the effects of fluid-seabed interaction and seabed-bedrock interaction on the wave characteristics, wave-induced and vertical earthquake-induced responses were investigated in detail.