黄土中砂层对入渗特性的影响

Influence of Sand Loess on Infiltration Characteristics

本文根据土壤水的能量原理，对砂层在黄土中的入渗特性进行了室内一维土柱的入渗试验研究及数学模拟。结果表明：在黄土中设置砂层不仅具有良好的阻水性，使下渗水流在一定限度内滞留于砂层以上的土体内，增加了上层土壤的持水能力；而且还具有减渗性，使下渗水量及入渗锋面的湿润速度明显减小，并且还可将下渗的非线性过程转化为线性过程，从而使整个入渗过程进入一个具有较小入渗率的稳渗阶段。本项研究结果为在黄土地区采用设置砂层的方法，作为水利、建筑工程以及西北农村窑洞民居的一项防渗、减渗的工程技术措施提供了理论依据。

Based on the energy theory of soil water,this paper studied the influence of sand layer in loess column oninfiltration characteristics by laboratory experiments and mathematical simulation. The results showed that sand layer embedded in the loess soils is characterised not only by improved water-tightness, which can make infiltrationflow stay on sand layer in soil body to a certain limited exent so as to improve water detention capacity in upper soillayer,but also by decreased infiltration flow and wetting velocity, which convert the non-linear process of infiltra-tion into the linear process, thus rendering the whole infiltration process to enter into the stable infiltration stagewith a smaller infiltration rate. Accordingly the results of this paper have provided the theroretical basis for the adop-tation of setting up sand layer in the loess soil as an important engineering practice for the infiltration prevention in the water conservancy work.