Discrete modelling of hydro-chemo-mechanical performance of clay materials

Abstract

The truncated octahedron cellular assemblies are used to represent the clay materials which align with experimentally characterised microstructures. The cellular assembly is divided into two interacting graphs: one is the mechanical graph which is developed to describe the deformation behaviour of the material, and the other is physical/chemical graph which is developed to demonstrate the reactive transport in the material. This setting is realistic especially when the mechanically-driven cracking has an impact on the transport pathways. Both graphs can represent the anisotropy and heterogeneity of the materials. The model performance is demonstrated using experimental data on the diffusion of species through Opalinus clay (OPA) – a complex process that involves elastic response, diffusion and anionic exclusion. The accuracy of the model is validated by the simulating the confining pressure and reactions dependency of different species transport through OPA. The model improves the understanding of the microstructure influence on the macroscopic transport properties of porous materials. The developed model can be applied to a variety of scientific and engineering problems, such as hydraulic cracking of gas-bearing shale, radioactive nuclear waste geo-disposal, contaminated soil remediation and geological carbon storage.