ABSTRACT
Data of the water retention domain measured on upper Jurassic marl from Portugal are presented. Under drying and wetting cycles physical degradation was observed, which causes an evolution of the microstructure and of the water retention domain of the material. Classical water retention models from the literature are not able to account for evolving retention domain with degradation, unless the parameters are adapted as the number of drying and wetting cycles increases. A different approach is proposed here, based on microstructure data, which quantify the changes in the microstructural void ratio. The model is able to describe the evolving retention domain, by accounting for the changes in the amount of water stored in the material as a function of its void ratio. In this way the effects of hydro-mechanical coupling and degradation of the material on its hydraulic behaviour may be correctly reproduced.
