Modelling gas migration through clays

摘要

Gas migration through compacted clay barriers has received considerable attention in recent times in connection with the long-term performances of isolating barriers around nuclear wastes (low as well as high radioactive levels). Gas migration experiments conducted in the laboratory try to simulate field conditions. The paper describes the simulation of some gas flow experiments conducted, on natural clay samples, under triaxial state conditions. A general coupled flow-deformation model for unsaturated soils was used in the simulations. An elastoplastic model was used to describe the stress-strain behaviour of the soil. The analysis shows that two key aspects are the variation of gas relative permeability with saturation and the irreducible saturation value. The paper presents a comparison between simulated and actual experimental results.