5种砂土水分特征曲线的测试分析

为了测试分析5种砂土的水分特征曲线,运用张力计法对砾砂、粗砂、中砂、细砂、粉砂5种砂土在不同含水率下的土壤基质吸力进行实验研究,并对数据进行了三次多项式与Van Genuchten模型的拟合与验证。结果表明:细砂的水分特征曲线呈"反S"形曲线,砾砂、粗砂、中砂、粉砂呈"L"形曲线;在相同含水率条件下,5种砂土的基质吸力大小为粉砂细砂中砂粗砂砾砂;三次多项式拟合结果的R2值、PBIAS值分别为0.982 7~0.998 3、-0.119 8~0.342 7,Van Genuchten拟合结果的R2值、PBIAS值分别为0.931 0~0.992 6、-2.083 5~5.256 7,此处3次多项式拟合效果要优于Van Genuchten模型。

Test and Analysis of Five Kinds of Soil Moisture Characteristic Curve

Using the method of tensiometer, the matrix suction of 5 kinds of sand, including gravel sand, coarse sand, medium sand, fine sand, silty sand, under different water content are researched experimentally, and the data is fitted and verified by three degree polynomial and Van Genuchtenmodel.The results show that: the soil water characteristic curve of fine sand shows "S" type curve, while that of gravelly sand, coarse sand, medium sand, silty sand shows "L" type curve;under the same water content, the order of the matrix suction from large to small is silty sand, fine sand, medium sand, coarse sand, gravelly sand;the R+2 value and PBIAS value for the fitting results of three degree polynomial is 0.982 7~0.998 3,-0.119 8~0.342 7, respectively;while the R+2 value and PBIAS value for the fitting results of Van Genuchten model is 0.931 0~0.992 6,-2.083 5~5.256 7, respectively;the fitting effect of the three degree polynomial is better than that of the Van Genuchten model.