摘要
为采用水力学参数特性揭示黄土高原沟壑区工程堆积体坡面土壤侵蚀过程,开展了野外放水冲刷试验。通过组合不同流量（35、45、55L/min）、不同坡度（24°、28°、32°）的试验,对坡面沟蚀发生发展过程中的水力学参数特性进行了研究。结果表明,坡面细沟水流的平均流速与水深主要受流量控制,二者均与单宽流量呈幂函数关系,且流速随冲刷时间的持续和冲刷形态的变化呈现上下起伏—瞬时增大—稳定的波动或减小—趋于稳定的变化历程。在所有坡度和流量范围内,雷诺数Re在42.9-1 082.8之间变化,雷诺数Re随坡度的增大呈先减小后增大的抛物线趋势。由坡面流弗劳德数Fr随冲刷历时变化情况表明,坡面径流形态是由急流向缓流发展。阻力系数f在0.019-0.94之间变化,f随坡度的增加先减小后增加,且随雷诺数Re的增大而增大,二者之间呈显著的指数函数关系。粗糙系数n随雷诺数增大而增大,且其与雷诺数存在显著性的指数函数关系。研究结果可为工程堆积体土壤侵蚀预报模型的建立提供一定的参数,对解决生产建设项目弃土弃渣场、取土场等水土流失问题具有重要的作用。
To explore the hydraulic mechanisms of runoff and sediment yield in slopes of engineering accumulation,a field runoff-scouring experiment was conducted under different flow discharges and different steep gradients. Results showed that the mean flow velocity and depth were mainly influenced by inflow discharge,and both had a power function relationship with flow discharge. The Reynolds number of the slope flow varies between 42. 9 and 1082. 8 in the erosion process. With the increase of the slope gradients,the Reynolds number decreased at first and then increased. The Froude number scour diachronic changes suggested that the form of slope surface runoff was developed from jet to slowly. Drag coefficient f was influenced by slope gradients and flow rate,with values between 0. 019 - 0. 94. With increasing slope degree,drag coefficient f decreased at first and then increased. Both drag coefficient f and roughness coefficient n showed a significant power function relationship with Reynolds number.
出处
《泥沙研究》
CSCD
北大核心
2016年第4期34-40,共7页
Journal of Sediment Research
基金
"十二五"国家科技支撑计划课题(2011BAD31B01)
关键词
工程堆积体
陡坡
放水冲刷
细沟侵蚀
水力学特性
黄土高原沟壑区
engineering deposit
steep slope
runoff scouring
hydrodynamic characteristics
gully region of loess plateau
