伊犁河流域裸露缓坡地放水试验研究
Scouring erosion experiment on bare slight slope in Ili River Basin
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摘要: 通过野外径流小区实地放水冲刷试验,研究伊犁河流域裸露缓坡地在不同放水条件下土壤水分变化、径流泥沙特征,并运用水力学理论分析坡面径流水力学参数特征。结果表明:1)土壤入渗率随着放水流量的增加呈现递增的趋势,随着放水量的增加,土壤表层含水量增大,入渗率随之减少,坡下部土壤水分变化量高于坡上;2)随着放水流量的增加,输沙率呈现递增的趋势,含沙量呈先增后减的趋势,含沙量与放水流量存在较好的幂函数关系,随着冲刷时间的延长,含沙量、输沙率均呈现递减的趋势;3)随着放水流量的增加,径流平均流速、雷诺数、Darcy-Weisbach阻力系数逐渐增大,弗劳德数逐渐减小,流速与流量、弗劳德数与雷诺数均呈良好的幂函数关系,水流为层流、急流状态。Abstract: Based on the scouring erosion experiment on bare slight slope in Ili River Basin,water infiltration and the characteristics of runoff and sediment were studied,and the hydraulic parameters characteristics of surface runoff were analyzed.The results showed: 1) Soil infiltration rate took on the trend of increasing as the scouring water discharge increased;however,it had a trend of decreasing with the scouring water amount increasing.A higher variation of soil water had on the lower slope compared to the upper slope.2) The process of sediment discharge went up as the scouring water discharge increased,and the sediment concentration had a trend from high to low.The relation between the sediment concentration and the scouring water discharge presented a power function.With the scouring time continuing the sediment concentration and the sediment discharge both went down.3) The average flow velocity,the Reynolds number and the Darcy-Weisbach resistance coefficient increased as the scouring water discharge increased,the Froude number decreased as the scouring water discharge increased.The relation between the average flow velocity and the scouring water discharge,the Froude number and the Reynolds number both presented power functions.The water flow presented a laminar,supercritical flow state.
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