Temperature-Dependent SWCC Model for Unsaturated Soil

Abstract

The soil–water characteristic curve (SWCC) model considering the temperature effect is significant in precisely predicting the relationship between the matric suction and degree of saturation in unsaturated soils in geotechnical and geoenvironmental engineering. In this work, we derived a new temperature-dependent wetting coefficient, incorporating a nonlinear temperature-dependent enthalpy of immersion per unit area. We introduce a simplified expression that successfully approximates the wetting coefficient for temperatures between 273.15 and 373.15 K. In addition, we propose a temperature-dependent matric suction equation and a temperature-dependent SWCC model. The new model comprehensively considers the temperature sensitivities of the water–air interface tension and wetting coefficient, which shows that an increase in temperature for a given matric suction leads to a decrease in the degree of saturation. The results illustrate that the new model is suitable for predicting the nonisothermal SWCC of unsaturated soils.