非饱和土壤水扩散系数的变化特征

The Changing Characteristics of Hydraulic Diffusivity in Unsaturated Soil

用水平土柱吸渗法对不同土壤和同类不同干容重的土壤水扩散系数进行了测定和计算。其结果表明，土壤水扩散系数是土壤含水量的指数函数，且随含水量的降低、于容重的增大及细粒含量的增多而减少；含水量在薄膜水范围内，则土壤水扩散系数是随干容重的增大及细粒含量的增多而增大。

The hydraulic diffusivities in the differen kinds of soils and the same kind of soil withdifferent dry densities have been determined and calculated by means of horizontal soil col－umn wet front advancing method． The data show that the hydraulic diffusivity in the soils isan exponential function of water content． And it decreases with decreasing of the water con－tent and increasing of the dry density and fine soil grain content In the range of water con－tent in which all of the water in soil exists as film water，the hydraulic diffusivity increaseswith increasing of the dry density and fine soil grain content．