A Global Matrix Method for Arbitrary Types of Layered Media Based on Generalized Saturated Porous Medium Model

Realistic shallow surface models often contain layered configurations of different types of media, which poses a challenge to wave propagation simulation. The traditional transfer matrix method requires cumbersome re-deriving of formulas and re-programming when dealing with different layered configurations. In this study, a unified algorithm, termed the global matrix method, is derived based on generalized saturated porous medium model for solving wave problems for arbitrary types of layered media (including fluid, solid, and saturated porous media) and their arbitrary combinations. The discontinuous properties between two different media are handled by a novel, universal interface continuity condition. The global matrix method is applied to solve the plane wave problem for three typical layered configurations, including the layered marine site, the layered soils containing groundwater, and the layered polar marine site overlying ice sheets. Furthermore, the effects of some parameters on the results are also analyzed. The results sufficiently illustrate the correctness of the global matrix method and its generality for different layered configurations. In any case, this method provides a uniform and convenient option for solving the free field for earthquake engineering.