基于分形理论配沙对粘质盐土饱和导水率的影响研究

Research on the Influence of Sand Distribution on the Saturated Hydraulic Conductivity of Clayey Saline Soil Based on Fractal Theory

为研究配沙量对粘质盐土重量分布分形维数和饱和导水率的影响,明确分形维数与饱和导水率之间的关系。以黄河三角洲引黄渠道内亟须处理的淤积泥沙为改良剂,对粘质盐土进行室内和田间配沙改良。试验采用湿筛-吸管法测定土壤颗粒级配,变水头法测定饱和导水率,分析建立配沙量、分形维数和饱和导水率之间的关系方程,同时通过田间试验对室内试验进行验证。结果表明:①引黄泥沙与粘质盐土颗粒级配明显不同,随着配沙量的增加,土壤的颗粒级配明显改变。②配沙量增加,分形维数显著降低,分形维数D与配沙量x的拟合方程为D=-0.05051 e^(0.01851 x)+2.891;配沙量增加,饱和导水率呈指数式上升,饱和导水率Ks与配沙量x的拟合方程为Ks=0.02561^( e0.04931 x)。③土壤饱和导水率Ks随分形维数D增加而降低,D与Ks的拟合方程为Ks=4.94×10^(8) e^(-7.246) D-0.5411。④田间试验从S0到S7处理,土壤饱和导水率显著增加,饱和导水率的估算值与田间试验实测值误差较小。因此,配沙可有效提高粘质盐土的饱和导水率,使用D与Ks拟合方程估算的土壤饱和导水率精度较高。

In order to study the influence of sediment content on the fractal dimension and saturated hydraulic conductivity of the weight distribution of clayey saline soil,the relationship equation between the fractal dimension and saturated hydraulic conductivity was studied.The silt that needs to be treated urgently in the Yellow River Delta diversion channel was used as the modifier to improve the clay saline soil indoor and field.The wet sieve-pipe method was used to determine the soil particle gradation,and the saturated hydraulic conductivity was determined by the variable head method.The relationship equation between the amount of sand,the fractal dimension and the saturated hydraulic conductivity was analyzed and established,and the field experiments were conducted to verify the indoor test.The results showed that:(1)The particle gradation of yellow-diluted sediment and clayey saline soil was obviously different.With the increase of the amount of sand,the particle gradation and texture of the soil changed significantly.(2)As the amount of sand distribution increased,the fractal dimension decreased significantly.The fitting equation between the fractal dimension and the amount of sand distribution was D=-0.05051 e^(0.01851 x)+2.891.When the amount of sand distribution increased,the saturated hydraulic conductivity increased exponentially,and the fitting equation of saturated hydraulic conductivity Ks and sediment distribution amount x was Ks=0.02561 e^(0.04931 x).(3)The saturated hydraulic conductivity of soil decreased with the increase of fractal dimension.The fitting equation of D-Ks was Ks=4.94×10^(8)e^(-7.246D)-0.5411.(4)In the field test from S0 to S7 treatment,the saturated hydraulic conductivity of the soil increased significantly,and the error between the cumulative value of saturated hydraulic conductivity and the measured value in the field test was small.Therefore,sand distribution can effectively improve the saturated hydraulic conductivity of clayey saline soil,and the accuracy of the saturated hydraulic conductivity estimated by the D-Ks fitting equation is higher.