Response of Porous Seabed to Dynamic Loadings

Abstract

The evaluation of the seabed response, including pore pressure, effective stresses and shear stresses, is particularly important for coastal geotechnical engineers involved in the design of foundation around marine structures. This paper consists of two components. The first component focuses on analytical approximation for the seabed response, in which a new analytical solution for the seabed response due to combined wave and current loading is presented. Both transient and residual mechanisms are considered. Based on the new analytical solution, the effects of currents on the seabed response are examined and a modified J-S curve is presented. The second component will present an integrated model for ocean waves propagating over a submerged coastal structure. In the new model, Navier-Stoke equations, Biot’s poro-elastic theory, and structural mechanics theory are solved for wave propagation, seabed response and structure deformation, respectively. The new feature of this model is to integrate wave, soil and structure modes into one model within COMSOL Multiphysics environments. In this part, we first present the model of ocean wave generation over a porous seabed. Then we further consider two coastal engineering problems: (1) ocean waves propagating over a submerged breakwater on a porous seabed; and (2) waves over a deformable structure on a porous seabed, which can be applied to wave energy converter.