室内基于土壤水分再分布过程推求紫色土导水参数

Determination of purple soil hydraulic parameters based on soil water redistribution in laboratory

选择三峡库区3种不同质地的紫色土,室内通过土壤水分再分布试验,探讨基于土壤水分再分布过程推求导水参数对于紫色土的适用性。结果显示,结合土壤水分垂直和水平再分布过程推求的紫色土水分扩散率与实测值具有很好的一致性,但推求的非饱和导水率偏差较大。然而,选用单一的土壤水分再分布过程结合实测水分特征曲线推求的紫色土非饱和导水率与实测值具有良好的一致性。湿润锋湿度与湿润剖面平均湿度不同函数关系对推求非饱和导水率和水分扩散率差异不明显。此外,基于土壤水分再分布过程推求导水参数方法比较适合低湿土壤的非饱和导水参数推求。

Through conducting experiments of soil water redistribution in laboratory, an approach of determining soil unsaturated hydraulic conductivity and diffusivity based on the redistributions of soil water, and its applicability on three different textural purple soils were discussed. The results show that the purple soil unsaturated hydraulic diffusivity based on the redistributions of soil water both vertically and horizontally is in good agreement with the measured values and its unsaturated hydraulic conductivities determined by the same method deviate greatly from the mesured values. However, the ones determined by combining one-dimension redistributions of soil water with measured soil water retention curve agree well with the measured values. Differentiation between unsaturated hydraulic diffusivity and unsaturated hydraulic conductivities detemined by the diffemet function relationships between soil moisture of wetting front and average moisture of wetted zone is not significant. In addition, this approach for determining soil hydraulic parameters based on soil water redistribution is more suitable for the lower soil moisture.