A Novel Hysteretic Soil–Water Retention Model with Contact Angle-Dependent Capillarity

Abstract

Considering the hydraulic hysteresis caused by the change of contact angle at the soil–capillary water interface during the drying–wetting processes, this note proposes a novel hysteretic water-retention model. Compared with the previous studies, the model can take into account two distinct mechanisms, i.e., capillarity and adsorption, separately. The capillarity instead of adsorption is related to the contact angle hysteresis. Based on the Young–Laplace equation and the conjugate point on the main drying–wetting curve, the scanning equation is determined for the capillary part. It is evident that the new model is able to capture the hydraulic hysteresis behavior by comparing against experimental data from the published literature.