Coupled Large Strain Deformation and Solute Transport in Saturated Multi-Layer Porous Media

摘要

The phenomenon of coupled porous media deformation and solute transport occurs in a variety of geoenvironmental engineering applications. This paper presents an extensively verified numerical model (named CST3) for coupled large strain deformation and solute transport in saturated, multi-layer porous media. The deformation algorithm accounts for vertical strain, media self-weight, general constitutive relationships, relative velocity of fluid and solid phases, changing compressibility and hydraulic conductivity during deformation, unloading/reloading effect, time-dependent loading and boundary conditions, external hydraulic gradient, and multiple layers of porous media with different material properties. Large strain can be considered such that the nonlinearity of material properties such as compressibility and hydraulic conductivity can be accounted for. The solute transport algorithm accounts for advection, diffusion, mechanical dispersion, linear and nonlinear sorption, equilibrium and non-equilibrium sorption, media porosity-dependent effective diffusion coefficient, and first-order decay reactions. A hypothetical problem is simulated using CST3, and to illustrate the importance of coupling between deformation and transport, two simulation cases are considered: one case takes into account the coupling effect between soil deformation and solute transport whereas the other ignores such coupling effect and assumes soil media does not deform. Simulation results indicate that soil deformation can have significant impact on the solute transport process for a long period of time. For relevant engineering applications, ignoring such coupling effect can lead to significant errors in the associated design and analysis.