地表模拟覆盖率对坡面流阻力的影响

Impact of Simulated Surface Cover on Resistance Coefficient of Overland Flow

采用变坡实验水槽在较大坡度（5°-25°）、流量（0.25-2 L/s）和覆盖率（0-25%）范围内,系统研究了坡面流阻力系数与坡度、流量、覆盖率、流态之间的关系。结果表明：阻力系数随着覆盖率增加呈幂指数增加（f=0.1013×（1-Cr）-8.573,R2=0.9）;f-Re呈负相关关系,并且随着流量的增加,负相关关系越来越显著;f-Fr呈负相关关系,随着覆盖率的增加,负相关关系越来越显著。通过因子分析发现：f=0.185（1-Cr）-6.137Fr-0.438（R2=0.934）,可以用来计算地表覆盖条件下坡面流阻力系数。研究结果有助于从水动力学角度分析坡面侵蚀、产沙过程,对土壤侵蚀过程模型的建立具有一定的指导意义。

This study discussed the relationship between overland flow resistance coefficient and slope,discharge,coverage rate and flow regime systematically.Resistance coefficient was simulated in an experimental flume with varying slope in a large scale of slope gradient（5°~25°）,flow discharge（0.25~2 L/s） and coverage rate（0~25%）.The result indicated that resistance coefficient increased with the coverage rate by power function（f=0.1013×（1-Cr）-8.573,R2=0.9）.The relationship between resistance coefficient and Reynolds number was negative,which were more and more significant with flow discharge increasing.And the relationship between resistance coefficient and Froude number was negative,which were more and more significant with coverage rate increasing.Simple empirical equations（f=0.185（1-Cr）-6.137Fr-0.438,R2=0.934） based on all influence factors,can be used to predict the resistance coefficient of overland flow with steep slope and surface coverage.The research of resistance characteristics on the steep overland with coverage,is helpful to analysis overland erosion and sediment yield process by way of dynamics,and has certain guiding sense to establish soil erosion model.