不同覆盖度和雨强条件下崩积体坡面侵蚀的动力学特征

The Characteristics of Hydrodynamics in the Slope Erosion of Colluvial Deposits Under Different Straw Coverage and Rainfall Intensity

基于崩岗崩积体易侵蚀的特性,通过室内人工模拟降雨试验,研究30°坡度条件下,不同秸秆覆盖度（0,25%,50%,75%,100%）和雨强（60,90,120mm/h）组合坡面侵蚀的水动力学参数特征。结果表明：（1）不同条件下,雷诺数变化范围在462.86~750.19Re之间,雨强对雷诺数的影响达到极显著水平,覆盖度对雷诺数的影响不显著;弗罗德数的变化范围在0.06~0.64Fr之间,水流的流型为缓流,覆盖度对弗罗德数的影响达到极显著水平,雨强对弗罗德数的影响不显著;阻力系数的变化范围在9.65~1 018.19f之间。（2）覆盖度对坡面流流速的影响达到极显著水平,坡面流流速随着覆盖度的增加而减小;覆盖度对水深的影响达到显著水平,坡面径流深随着覆盖度的增大而增加;阻力系数与雨强和覆盖度之间无明显关系。（3）覆盖度与单位水流功率之间呈极显著的指数函数关系,与水流剪切力和断面单位能量之间呈显著的指数函数关系;雨强对流速、水深和阻力系数的影响都不显著。

Due to the highly erodible characteristics of colluvial deposits,and through the simulation of rainfall in laboratory,this study intended to disclose the characteristics of hydrodynamics in the slope erosion of colluvial deposits under different straw coverage（0,25%,50%,75%,100%）and different rainfall intensity（60,90,120mm/h）in the condition of 30°slope.The main outcomes showed that：（1）Under different conditions,the range of Reynolds number changed from 462.86 Re to 750.19 Re.The influence of rainfall intensity on the Reynolds number reached a highly remarkable level,while the influence of straw coverage on the Reynolds number was not significant.The range of Froude number varied from 0.06 Fr to 0.64 Fr,and the flow pattern of water was slow flow.The influence of straw coverage on the Froude number reached an extremely notable level.The influence of rainfall intensity on the Froude number was not obvious.The range of resistance coefficient transformed from 9.65 fto 1 018.19 f.（2）The influence of straw coverage on the flow velocity reached a highly significant level,and the flow velocity decreased with the increase of straw coverage.The influence of straw coverage on the flow depth reached a remarkable level,and the flow depth increased with the increase of straw coverage.The resistance coefficient had no significant relationship with straw coverage and rainfall intensity.（3）There was a highly striking exponential relationship between the straw coverage and unit stream power,and there was also a significant exponential relationship between the straw coverage and the hydrodynamic shear stress or specific energy in sections.The rainfall intensity had no significant influence on flow depth,flow velocity and resistance coefficient.