The Effects of Relative Velocities and Accelerations of the Pore Fluids on the Dynamic Behavior of Unsaturated Soils

Unsaturated soils are three-phase porous media consisting of a solid skeleton, pore liquid, and pore gas. The overall behavior of unsaturated soils is influenced not only by these three bulk phases, but also by the interfaces between them. The coupled mathematical equations governing the dynamics of unsaturated soils can be derived based on the theory of mixtures with interfaces (TMI). Solution of these equations requires large computational resources. A framework-based parallel finite element code was developed for efficiently solving such large problems. Simulation of an unsaturated soil embankment subjected to earthquake loading is presented to show the capabilities of the computer code developed. A reduced set of governing equations, neglecting the relative accelerations and velocities of fluids, is also solved to study the effects of these quantities on the overall dynamic behavior of unsaturated soils. The reduced set of equations gives comparable results to that of the complete set of equations for a low permeable soil considered in this study.