Numerical modeling of multiphase flow and transport processes in cohesive soils and parameter identification strategies

The numerical simulation of multiphase flow and transport processes in porous media is gaining increasing importance various application fields such as oil recovery and environmental engineering. The multiphase flow and transport processes in cohesive soils in particular are of great interest for nuclear repositories and municipal waste-disposal sites. As cohesive soils show a characteristic swelling/shrinking behavior, model concepts for these soils must also account for structural alterations and their influence on the hydraulic properties. A two-phase two-component model concept is presented that phenomenologically allows for structural alterations. The effects of swelling/shrinking on the flow and transport processes are taken into account by adapting the relevant hydraulic parameters. This adaptation is based on constitutive relationships for the porosity, permeability, and capillary pressure. These constitutive relations involve additional input parameters that, intensify the problem of parameter identification. Therefore, a concept for the systematic determination of the relevant input parameters is developed. Inverse modeling techniques are used for both designing appropriate experimental setups to provide a convenient database and quantifying parameter values.