Coupled Thermohydromechanical Double-Structure Model for Expansive Soils

In this paper, development of a thermohydromechanical model for expansive soils including double structure is described. The model is based on the previously developed double-structure hypoplastic model, in which hydromechanical coupling is considered at each of the two structural levels. The model also includes separate effective stress definitions and water retention curves for the two levels of structure, and they are linked through the double-structure coupling function. In the proposed model, thermal effects are considered on the mechanical behavior of both the macrostructure and the microstructure. This is combined with a temperature-dependent water retention curve for the macrostructure and an enhanced double-structure coupling law. Good predictions of the model are demonstrated by comparing the simulations with experimental data on MX80 bentonite taken from the literature. (C) 2017 American Society of Civil Engineers.