Soil-water retention curve model for fine-grained soils accounting for void ratio–dependent capillarity.

This paper presents a soil-water retention curve (SWRC) model for fine-grained soils. Compared with existing studies, the proposed model accounts for the distinct roles of the volume change of soils on capillarity and adsorption mechanisms. The capillary water is described by a relation that includes the characteristics of the pore-size distributions as parameters, while the absorbed water is modeled by a novel proposition that both considers the phenomenon of capillary condensation and allows for the decoupling between the degree of capillary and adsorptive saturation. Based on this feature, the void ratio effects are considered in a way in which they only affect capillary water, i.e., consistent with how volume change influences soil microstructures. The relative contributions of void ratio effects and hydraulic hysteresis on the path- and history-dependence of a SWRC in Sr–s–e space, where Sr is degree of saturation, s is matric suction, e is void ratio, for deformable unsaturated soils are examined. The significance of discriminating the effects of volume change on capillary and adsorptive water is illustrated by applying the SWRC model to computing the shear strength of unsaturated soils with different void ratios. The model performance is assessed by comparing against test data reported for four types of fine-grained soils in the literature and those tested for natural loess in this work. [ABSTRACT FROM AUTHOR]