Comparing double porosity and single porosity models for the simulation of coupled chemo-hydro-mechanical behavior of compacted active clays

This note evaluates the implications of adopting different types of models to reproduce the chemo-hydro-mechanical behavior of compacted active clays exposed to processes of salinization and desalinization. First, experimental observations and theoretical considerations pertinent to a double porosity formulation of the problem are introduced. Fundamental equations are then re-formulated according to a simpler single porosity frame. Finally results of diffusion tests performed to highlight the coupled chemo-hydro-mechanical behavior of the soil are reproduced by means of the two different models. In order to reproduce the experimental results is not sufficient to invoke mechanical non-linearities; it is also necessary to introduce non-linear hysteretic adsorption isotherms. However, the physical meaning of the required adsorption parameters is doubtful, which demonstrates the limitations of the single porosity model in tackling these types of phenomena. © 2015 Taylor & Francis Group.