利用MATLAB拟合压实黄土土水特征曲线的研究

Study of Fitting Soil-water Characteristic Curves for Compacted Loess by MATLAB

为了找到准确且简便的拟合压实黄土的SWCC的模型与方法,利用压实黄土入渗试验得到的体积含水率与基质吸力的数据,选用MATLAB的lsqcurvefit,nlinfit和fminunc三种函数为拟合方法,分别拟合了适用性较广的van-Genuchten模型和Gardner模型的土水特征曲线,并进行了拟合比较。结果表明,在本课题研究范围内,利用fminunc函数采用Gardner模型拟合压实黄土SWCC效果最好;平行试验数据的验证结果表明误差小于10%。利用MATLAB的fminunc函数通过Gardner模型拟合压实黄土土水特征曲线是一个既方便又准确的方法。

Three functions in MATLAB, i. e. lsqcurvefit, nlinfit and fminunc, were used to find a convenient and accurate way to fit soil water charactieristic curve（SWCC） of compacted loess,by using van Genuchten model and Gardner model separately. The fitting data of volumetric water content and matrix suction were obtained by one dimensional infiltration test of compacted loess. The analysis on fitting effects shows that the fitting result of Gardner model by fminunc function is the best among the methods used in this study. Finally,the data from a parallel test were used to verify the fitting formulae. The er rors between calculated and measured data are less than 10% ,which further verifies that Gardner model fitting SWCC of compacted loess by using fminunc of MATLAB is convenient,stable and accurate.