A water retention curve model for deformable soils based on pore size distribution

It has been recognized that the pore size distribution plays a decisive role in the water retention curve of soils. Although the pore size distribution evolves in a rather complicate way during deformation, experimental observations have shown that the overall shape and the distribution characteristics of the pore size distribution are not significantly altered. Based on these findings, it is assumed that the pore size distribution in a deformed state can be obtained from the pore size distribution in a reference state by horizontal shifting and vertical scaling of the pore size distribution function. On this basis, a water retention curve model is formulated to account for the effects of soil deformation and hydraulic hysteresis. Benefited from the characterization of the effects of soil deformation on the water retention curve by the change of pore size distribution, the proposed model contains a compact set of seven parameters with clear physical meanings, which can be easily calibrated by regular laboratory tests. The proposed model is finally validated against a number of laboratory tests, showing good agreements between the model predictions and the experimental measurements.