(土娄)土坡面降雨水沙运移实验研究

黄土高原是我国植被破坏与水土流失最为严重的地区。本文基于室内坡地降雨实验,分析了塿土坡面降雨入渗补给系数的变化,对比了不同雨强影响下径流泥沙含量和累积泥沙含量的时间变化趋势,并将侵蚀与入渗结合,分析了同时段产沙量和入渗率的变化关系,研究表明:入渗补给系数随雨强增大而逐渐减小,两者可描述为线性关系,雨强越小,入渗补给系数越高;降雨初始产沙值最大,在产沙10 min内变缓。雨强大的,初始产沙量和稳定沙量都稍大,但总体差异不大,产沙量分布曲线形状与入渗率曲线极为相似;不同雨强下累积泥沙量与降雨历时之间存在明显的幂函数关系,且幂函数的指数部分基本随降雨雨强增加而逐渐增加;不同雨强下入渗率和累积泥沙量的变化趋势相反,当累积泥沙量增加,相应的土壤入渗率减小,两者变化趋势随雨强增大而趋于明显。

Experiment Studies on Water and Sediment Movement for Lou Soil During Rainfall on Loess Slope Land

There are close relations between the development of Loess Plateau and breaking-off of Yellow River.In this paper,based on rainfall experiments of Lou soil,the variation trends of infiltration supplement coefficient to rainfall were analyzed,the time variation trends of sediment content in runoff and the cumulative sediment content were compared at different rainfall intensities,furthermore,the erosion data was connected with infiltration characteristics to discuss their relations observed at the same time.The results showed: the infiltration supplement coefficient of rainfall decreased when the rainfall intensity increased,the smaller the rainfall intensity,the larger the rainfall infiltration supplement coefficients,and the linear functions were fitted well to them;at the beginning of rainfall,the biggest value of sediment content existed,but its variation trends became flat within 10 minutes of sediment producing.The larger the rainfall intensities,the larger the initial and steady sediment contents,but their total variation trends differs little.Moreover,there are similar trends of sediment distribution curve and infiltration ratio curve;good power functions was fitted for cumulative sediment content and rainfall time at different rainfall intensities,and the exponential part increased when the rainfall intensities increased.The variation trends of infiltration ratios differed with that of cumulative sediment content,when the cumulative sediment content increased,the corresponding infiltration rate decreased,their variation trends was obvious when the rainfall intensities increased.