Abstract: Air-entry value, as an important parameter of soil-water characteristic curve (SWCC), needs to be predicted in researching the hydraulic and mechanic properties of unsaturated deformable soils. A simple prediction model for the air-entry value of deformable soils was built by combining the Van Genuchten (VG) model with the variation law of SWCC under compression deformation condition. To verify the rationality of the model, experimental SWCC of Hunan clay were measured using pressure plate instrument, which are exploited to further obtain the measured value of air-entry value with different initial void ratios. The measured and predicted values were well consistent, indicating that the proposed model is of good performance. Moreover, VG model is used to simplify and unify the existing models of unsaturated relative permeability coefficient, and the validity and simplicity of this approach is verified.

Key words: air-entry value, clay, soil-water characteristic curve, Van Genuchten model, permeability coefficient of unsaturated soils