A coupled soil-pore fluid formulation for modeling soil liquefaction and cyclic mobility in seabed using the finite volume method

The stability of offshore structures, such as wind turbine foundations, breakwaters, and immersed tunnels can be strongly affected by the liquefaction and cyclic mobility phenomena in the seabed. Our goal is to develop a numerical code for analysis of these situations. For this purpose, we start by formulating the strong interactions between soil skeleton and the pore fluid via a coupled set of partial differential equations. A single bounding surface soil model capable of simulating the accumulations of pore pressures, strains, dilatancy, and strain „softening‟, is then adopted for quantifying the cyclic soil constitutive relations. To deal with the high non-linearity in the equations, the finite volume (FV) method is proposed for the numerical simulation. The corresponding discretization strategies and solution algorithms, including the conventional segregated method and the more recent block matrix solver, are discussed as well. Overall, investigations in this paper provide a methodology for developing a numerical code simulating liquefaction and cyclic mobility. In future work this will be implemented in practice with the aid of the open source CFD toolbox, OpenFOAM.