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土水特征曲线基本参数(如进气值、残余吸力值和过渡区脱湿曲线的斜率等)的确定是预测非饱和土强度、渗透性以及本构关系的基础。基于修正Fredlund和Xing拟合方程,提出单峰和双峰土水特征曲线基本参数的确定方法。首先,对试验数据点进行最优化拟合,获取拟合方程的参数,对于双峰土水特征曲线,根据试样的孔径分布特征将其分段进行拟合;其次,根据拟合方程的几何关系求出过渡区和残余区土水特征曲线的斜率及其切线方程;再根据切线方程可以准确地确定单峰和双峰土水特征曲线的进气值、残余吸力值等。最后,利用单峰和双峰土水特征曲线的试验数据,验证了此方法的可行性。
The determination of basic parameters of soil-water characteristic curve (such as intake value, residual suction value and slope of transition curve) is the basis for predicting the strength, permeability and constitutive relationship of unsaturated soil. Based on the modified Fredlund and Xing fitting equations, the method to determine the basic parameters of single-peak and double-peaked soil-water characteristic curves is proposed. Firstly, the experimental data points are optimized and fitted to obtain the parameters of the fitting equation. For the bimodal soil-water characteristic curve, the fitting is performed according to the pore size distribution of the sample. Secondly, according to the geometry of the fitting equation Relationship between the slope and the tangent equation of the soil-water characteristic curve of the transitional zone and the residual zone can be obtained. The inlet and residual suction values of the soil-water characteristic curves of the unimodal and bimodal peaks can be accurately determined according to the tangent equation. Finally, the experimental data of single-peak and double-peaked soil-water characteristic curves are used to verify the feasibility of this method.