A General Model for Temperature-Dependent Soil Suction

Soil suction is a crucial parameter that affects the behavior of unsaturated soils. The impact of temperature on suction can lead to significant changes in the hydromechanical response of unsaturated soils. However, current models that describe the temperature dependency of soil suction rely mainly on empirical and semiempirical relationships, which do not fully consider the contribution of soil structure and degree of saturation on enthalpy potential. To address this limitation, we propose a novel general model for temperature-dependent soil suction based on thermodynamic laws. The model accounts for the thermodynamic processes that determine the enthalpy of the soil and uses these processes to develop the mathematical relationships required for the model. Specifically, we expand the Gibbs free energy for both internal chemical exchanges and when dealing with the thermodynamic system as a whole. We then combine the resulting equations to obtain a general model for the soil total suction. The model is validated by comparing its predictions against laboratory-measured suction at different temperatures for different soils reported in the literature. Furthermore, we demonstrate the model's potential by showing an application in simulating the soil-water retention curve at different temperatures. The proposed model can contribute to a better understanding of the behavior of unsaturated soils under varying temperature conditions by providing a comprehensive and physics-based approach to modeling temperature-dependent soil suction.