产流积水法测量降雨侵蚀影响下坡地土壤入渗性能

Measurement of rainfall-erosion impacted soil infiltration capability of slope land with run-on-ponding water

坡地土壤降雨入渗性能与下垫面对降雨的再分配过程密切相关。该文提出了测量坡地降雨条件下土壤入渗能力的产流积水法。由水量平衡原理,根据径流在坡面上推进的过程和积水情况下积水深度随时间变化的过程,推导得到了计算土壤入渗性能的数学模型。采用两种工况:1)雨强为60 mm/h、坡度5°、径流面与入渗面长度比为1∶2;2)雨强30 mm/h、坡度20°、径流面与入渗面长度比为1∶1。进行室内试验,计算得到了两种工况的入渗性能曲线。分析了这种新型测量方法和计算模型的合理性。将时段降雨量和累计入渗量进行对比,估计了两种工况的测量误差。该方法可以克服传统的降雨器和双环入渗仪方法的不足,用于测量坡地降雨、径流、土壤侵蚀等因素影响下的整个降雨入渗性能过程曲线。为相关研究提供有力的工具。

Soil infiltration capability（IC） of slope lands is closely related to the rainfall redistributed on the surface. A new method for IC estimated from runoff-ponding water was advanced in this paper. Mathematic models were derived to compute the IC with data for the advance process of runoff and that of ponding depth on soil surface. Laboratory experiments of two cases（rainfall intensity of 60 mm/h, slope gradient of 5 degrees and runoff surface length of 1 m; and rainfall intensity of 30 mm/h, slope gradient of 20 degrees and runoff surface length of 1.5 m） were conducted to collect required data for the demonstration of the experimental and computational procedures to determine the IC curves. The rationale of the measurement and the related algorithms were justified. And comparisons of the cumulated infiltrated waster with rainfall amounts were made to determine the measurement errors to demonstrate the measurement accuracy of the method. The newly suggested method overcomes the shortcomings of the conventional rain simulator and double ring methods. This method has the capability of measuring the full IC curve of slope surface as influenced by rainfall splash, runoff, and soil erosion. This method may supply the researchers in related fields a useful tool.