黄土坡面细沟径流输沙过程试验研究

Experimental Research on Runoff-induced Sediment Discharge Processes of Rill on Loess Hill Slope

细沟侵蚀是黄土地区坡面最主要的侵蚀方式之一,输沙过程是细沟侵蚀中的重要环节,阐明细沟输沙过程对理解细沟侵蚀发生发展过程机理及治理坡面水土流失具有重要意义。该文采用具有定流量人工放水的组合小区模拟降雨试验,对黄土坡面细沟径流输沙过程进行研究,结果表明:(1)不同降雨强度及不同坡度下,细沟径流输沙率随径流过程的变化具有极大的相似性,都随径流历时的增加而逐步递增,可用幂函数方程很好地描述;(2)细沟径流输沙模数随降雨强度及坡度的增大皆相应增加,可分别用幂函数方程及指数方程很好地描述;(3)雨强及坡度的综合作用可用二元幂函数方程很好地描述,其中,二者的影响基本相当;(4)水流切应力是与细沟输沙动力学过程关系最密切的水动力学参数,细沟输沙动力学过程的发生发展根源于细沟水流剪切力的动力作用。

Rill erosion is the most important erosion way in slope land on the Loess Plateau.Sediment transport process is an important part of soil erosion.It is of great significance to study and simulate sediment transport processes for the mechanism of occurrence and development mechanism rill erosion and to protect the sustainable development of slope land.In this study,sediment transport processes of rill runoff on loess plateau slope soil were investigated by simulation experiment of using combinatorial flume under rainfall condition indoors.Results showed that： （1） Sediment transport rate of rill runoff is similar to runoff process,both them increasing with runoff diachronic.They could be characterized by power function equation;（2） Sediment transport modulus of rill runoff increase with slope and rainfall intensity.The correlation is available characterized by power function equation and exponential function equation;（3）The comprehensive function of slope and rainfall intensity could characterized by binary power function equation and the impact of them are almost equal;（4）Stream shear stress is a important hydrodynamic parameter and it is the root of development of rill sediment transport dynamics.