花岗岩残积土SWCC曲线拟合研究

Study on the Fitting SWCC of a Granite Residual Soil

土水特征曲线是是土壤的一种重要的水力力学参数,可以体现出土壤的渗透性、抗剪强度等性质。为了方便测定花岗岩残积土的SWCC曲线,探究更加快捷的拟合花岗岩残积土SWCC曲线的模型与方法,首先利用室内压力板仪实测了花岗岩残积土脱湿与吸湿过程中吸力与含水率对应的数据点,对于试验中的脱湿过程选用VanGenuchten模型,吸湿过程选用Gardner模型,利用MATLAB软件自带的lsqcurvefit、nlinfit函数分别进行了拟合,lsqcurvefit、nlinfit函数结果相近,拟合出的残差平方和均小于0.0001,结果表明lsqcurvefit函数和nlinfit函数对于花岗岩残积土SWCC曲线的拟合效果均良好,以后的研究中可任选一种使用。

The Soil Water Characteristic Curve(SWCC)is an important hydraulic parameter of soils,which can reflect the properties of soil samples such as the permeability and the shear strength.To facilitate the determination of the SWCC curve of a granite residual soil sample and to explore a more convenient as well as faster model and the method to fit the SWCC curve of granite residual soil,firstly,the data points corresponding to the suction and moisture content in the process of dehumidification and hygroscopicity of granite residual soil are measured by using an indoor plate pressure instrument.The Gardner model was used for the dehumidification process and the hygroscopic process.The results of lsqcurvefit and nlinfit functions in the MATLAB software are similar,and the sum of the squared residuals is less than 0.0001.The results show that both lsqcurvefit and nlinfit functions are good for the fitting SWCC curves of granite residual soils,and either one can be used in future studies.