资源环境科技发展态势分析平台

The soil‐water characteristic curve (SWCC) plays an essential role in the analysis of the shear strength, deformation, hydraulic conductivity, and aqueous diffusion of unsaturated soils. A review of methods proposed for fitting the main SWCCs is presented. The methods can be categorized into three groups, namely, (i) empirical methods, (ii) domain methods, and (iii) theoretical methods. A hysteretic model considering the contact angle hysteresis is proposed for fitting the main SWCCs based on a theoretical method. The model links the physical quantities at the micro‐and macro‐scale. Specifically, a modified expression describing the relationship between the volume of the liquid bridge and the water content is derived, and the contact angle hysteresis behavior is modeled based on the study of total thermodynamic potential energy. The model has a clear physical meaning, and the parameters can be obtained easily. Comparisons of the model simulation and experimental data show that the proposed model accurately captures the main features of the SWCC and describes the nonlinear relationship between the matric suction and the water content during wetting and drying processes.