The fitting analysis of soil-water characteristic curve (SWCC) is the foundation of engineering properties of unsaturated soils. The purpose of this paper is to explore the differences of fitting effects between different fractal and empirical models as well as the effect of residual water content θ_r on the model fitting. The experimental SWCCs of Hunan clay at different initial dry densities are measured by pressure plate instrument, and then they are fitted by fractal and empirical models. The effect of the limit of θ_r on the fitting results is analyzed by comparing the results of indoor evaporation test. The results show that within the measured data point range, fractal model II-2 and van Genuchten model (VG model) have the best fitting effect, fractal models I and II-1 take the second place, and the fitting effect of Gardner model is the worst. When the matrix suction is more than the measured data, the fitting accuracy of the model is poor. For the model with θ_r, reasonable limit range of θ_r can only improve the fitting accuracy of the model to a certain extent. For the fractal model, the fitting accuracy of the model can be improved effectively when θ_r is considered. Furthermore, the difference of fractal dimension and air-entry value in various fractal models are also discussed in this paper.

中文翻译：

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分形和经验模型中土壤水特征曲线的比较分析

土水特征曲线的拟合分析是非饱和土工程特性的基础。本文的目的是探索的不同的分形和经验模型之间拟合效果以及残留的水含量的效果的差异θ _ř在模型拟合。用压盘仪测量了湖南黏土在不同初始干密度下的实验SWCCs，然后通过分形和经验模型进行拟合。限的效果θ _ř通过比较室内蒸发测试的结果来分析拟合结果。结果表明，在测得的数据点范围内，分形模型II-2和van Genuchten模型（VG模型）具有最佳拟合效果，分形模型I和II-1位居第二，而Gardner模型的拟合效果为最差的。当基质吸力大于测量数据时，模型的拟合精度较差。对于与模型θ _{- [R} ，的合理限度范围θ _ř只能改善模型的拟合精度在一定程度上。对于分形模型，该模型的拟合精度可以有效地提高当θ _ř被认为。此外，本文还讨论了各种分形模型中分形维数和进气值的差异。