Abstract: The common wetting deformation of coarse grain soil is of crucial importance for the long-term safe operation of earth and rockfill dam. The fitting accuracy of existing empirical formulas is unclear. In view of this,experimental data was collected and verified. Results demonstrated that: 1) the relation between wetting volumetric deformation under constant pressure and confining pressure can be well fitted with power function;2) the relation between wetting axial strain and stress level can be well fitted with exponential function,and the parameters of exponential function are linearly related to confining pressure;3) a bilinear model with simple form for wetting volumetric strain has higher fitting accuracy than the power linear model and the six-parameter model;4) wetting shear strain is in a good hyperbolic relationship with stress level but a weak correlation with confining pressure. In addition,an empirical formula of wetting strain based on modified relative wetting stress level is established by analyzing the correlation between wetting strain and different stress levels.

Key words: wetting strain, empirical formula, stress levels, fit accuracy, correlation analysis