Thermo-hydro-mechanical coupling model of elastic modulus characteristic curve for unsaturated soils

The settlement has been reported to regularly be a fundamental factor in controlling the stability of geotechnical structures. Because the theory of elasto-plasticity is widely employed to predict the settlement, the elastic modulus is a vital parameter that is regularly utilized for theoretical calculation. Moreover, thermomechanical behaviour of unsaturated soils has recently received considerable attention because its importance in various energy geostructures applications, as well as in relation to climate change. This paper presents a coupled thermohydro-mechanical model of the elastic modulus characteristic curve (EMCC) that was developed based on the effective stress theories of unsaturated soils. The proposed model uses the soil-water characteristic curve (SWCC) and the modulus of elasticity under saturated conditions to predict the variation of modulus of elasticity with matric suction for unsaturated soils. The successful prediction performance of the proposed model is demonstrated by the comparison of measured and predicted outcomes for various published data sets in the literature related to different soil types. The proposed method was then used to present a parametric study considering the coupled impact of some important parameters on SWCC and EMCC. The analysis results indicated that the normalized elastic modulus rate increases with increasing matric suction, hydraulic conductivity, soil density, and with decreasing flow rates, temperatures, and normal stresses.