Models for predicting the soil-water characteristic curves for coarse and fine-grained soils

The focus of this paper is directed towards developing models for predicting the soil–water characteristic curves (SWCCs) for coarse- and fine-grained soils taking account influence of hysteresis and various factors such as the stress state and soil structure, respectively. For achieving this objective, several novel models are derived from the pore-size distribution (PoSD) curve of the SWCC and linked to the well-known SWCC fitting equations. Three simple methods are developed from the proposed model that can be used for predicting the scanning SWCCs of coarse-grained soils. A modified SWCC model is built based on the theoretical background developed for the PoSD curve that is capable for predicting the of fine-grained soils taking account influence of the initial water content and stress state. In addition, a coupled SWCC model is proposed that can be used for explaining the influence of multiple soil parameters. The proposed novel, yet simple models can be used in numerical modeling of complex coupled hydromechanical problems and for predicting of various properties of unsaturated soils.