A Formulation for Scanning Soil-water Characteristic Curves

The hysteretic nature of soil water characteristic curve (SWCC) is captured assuming the virgin drying and virgin wetting (a.k.a. imbibition) curves; which can be obtained from experiments or various fitting equations in the literature, bound all possible values during transition from one regime to the other. The scanning curves (transitions between virgin wetting and drying SWCC) are modelled by using geometry-based relations, which are devised by means of the observations on the shapes of graphs of experimental data found in the literature. The proposed relations can be used in incremental form to predict suction in different frameworks (e.g. infiltration, evaporation) and related physical problems. An empirical equation is proposed for power parameter (K), which is introduced in the relations. Only virgin wetting and virgin drying SWCCs and regime reversal point suffice to model a scanning curve in the developed formulations