关键词: 土-水特征曲线, 竖向应力, 进气值, 进水值, 试验, 拟合

Abstract: SWC-150 Fredlund soil water characteristic cell is used to test the soil-water characteristic curve (SWCC) of gravelly soils with different densities under different vertical stresses. The influence of the vertical stress and dry density on the SWCCs is investigated. The SWCCs are fitted based on Fredlund & Xing tri-parameter model using least-square method. The parameters of the model are determined and discussed. With the increase in the vertical stress and dry density, the model parameter n increases while m decreases. Except that the parameter a slightly decreases with the increase in the dry density during wetting process, it increases with the increase in the vertical stress and dry density. Based on the fitting results, the influence of the vertical stress and dry density on the air or water entry value and the slope of the SWCC are studied. The quantitative relationships between the air or water entry value, the slope of transition segment of the SWCC and the vertical stress, dry density are proposed. The results show that the air or water entry value has a positive linear relationship with the vertical stress and dry density. Nevertheless, the water entry value has little change with the change in the dry density. The slope of transition segment of the SWCC presents hyperbolic relationship with the vertical stress, while the relationship between the slope and the dry density is linear.

Key words: soil-water characteristic curve, vertical stress, air entry value, water entry value, test, fitting