An Elastoplastic Framework for Expansive Soils Based on Effective Stresses

In this paper, an elastoplastic framework for the volumetric behavior of expansive soils based on effective stresses is proposed. As proposed by other authors, this constitutive model separates the contribution of the microstructure and the macrostructure on the volumetric behavior including their interaction. The hydraulic behavior of the soil is simulated using a porous-solid model able to reproduce wetting-drying cycles in deforming porous materials. This porous-solid model is based on the current pore size distribution (PSD) of the soil. Therefore, the volumetric deformation of the sample can be related to the evolution of the PSD. The result is a fully coupled elastoplastic framework based on effective stresses able to reproduce the volumetric behavior of expansive soils. Some experimental and numerical comparisons show the ability of the model to simulate the behavior of expansive soils under different stress paths. These results also indicate that the precision of the model is highly dependent on the correct determination and modeling of the retention curves.