浑水膜孔灌多向交汇入渗及减渗特性

浑水灌溉是我国黄河流域引黄灌区灌溉的主要特点,其中浑水中的泥沙含量对土壤入渗特性有较大的影响,为揭示浑水膜孔灌交汇入渗的减渗特性,通过开展浑水及清水膜孔灌入渗试验,建立了浑水膜孔灌自由入渗相对于清水的减渗率及浑水膜孔灌多向交汇入渗相对于自由入渗的减渗率与入渗时间之间的量化关系,提出了由清水膜孔灌自由入渗量推求浑水膜孔灌多向交汇入渗量的模型。结果表明:浑水膜孔灌自由入渗较清水的减渗量随入渗时间的延长而增大,但增大幅度慢慢变小,入渗后期其减渗量基本呈线性增加,其减渗率随时间的增大先快速增大后缓慢减小,入渗后期减渗率基本稳定;当入渗产生交汇后,入渗能力明显减小,多向交汇入渗和单向交汇入渗相对自由入渗的减渗率均随入渗时间的增长而增大,多向交汇入渗相对单向交汇入渗也存在减渗作用,3条减渗率曲线的变化率随着时间的增长而逐渐减小。

Experimental Study on the Characteristics of Bilateral Interference Infiltration and Infiltration Reduction in Film Hole Irrigation with Muddy Water

Muddy water irrigation is the main feature of irrigation in the Yellow River irrigation area of the Yellow River Basin. The sediment content in muddy water has important impact on soil water infiltration. The muddy water and clean water film hole irrigation experiments were conducted to reveal the infiltration reduction characteristics of bilateral interference under muddy water film hole irrigation. The relationship between infiltration reduction rate of free infiltration under muddy water film hole irrigation compared to clean water and infiltration time, and the relationship between the infiltration reduction rate of bilateral interference under muddy water film hole irrigation compared to free infiltration and infiltration time had been established in this study. Then we proposed a model to reconstruct the infiltration volume of bilateral interference infiltration under film hole irrigation with muddy water by the infiltration volume of free infiltration under clean water film hole irrigation. The results showed that the infiltration reduction volume of free infiltration under muddy water irrigation compared with clean water increased with the increasing of infiltration time, but the increasing degree reduced gradually. The infiltration reduction volume increased linearly at the later stage of infiltration, and the infiltration reduction rate increased rapidly and then decreased slowly with the increasing of infiltration time. It maintained stable at the later stage of infiltration. The infiltration capacity reduced obviously when the intersection infiltration occurred. The infiltration reduction rates of bilateral interference infiltration and one-way intersection infiltration compared with free infiltration were both increased with the increasing of infiltration time. Compared with one-way intersection infiltration, the bilateral interference infiltration also had the effect of reducing infiltration. The change rates of three infiltration curves were decreased with the increasing of time.