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坡面流阻力是反映坡面流水力学特性的重要特征值。利用人工模拟降雨试验,定量研究了在45、87和127mm/h降雨强度下,20°陡坡面裸地、草地和灌木地的坡面流阻力变化特征。结果表明,由于植被覆盖措施的阻滞作用,相对于裸地坡面,草地和灌木地坡面径流阻力系数明显增大。草地和灌木坡面阻力系数分别是裸地坡面的5.58～7.45倍和5.61～6.26倍。不同被覆条件下坡面平均阻力系数与降雨强度关系密切,随降雨强度的增大呈减小趋势。同时,坡面流阻力系数受到降雨强度和下垫面条件发育形态的共同影响。建立了不同被覆坡面的复合非线性阻力系数计算公式,变量系数表明草被覆盖度和降雨强度对坡面流阻力大小有着决定性的影响。该研究对于揭示植被调控坡面产流产沙机理,为生态修复工程建设提供科学依据具有一定的科学意义。
Slope flow resistance is an important characteristic value that reflects the hydraulic characteristics of slope. Using artificial simulated rainfall test, the change characteristics of slope flow resistance on nudity, grassland and shrub land of 20 ° steep slope were quantitatively studied under the rainfall intensities of 45, 87 and 127 mm / h. The results show that, due to the retardation effect of vegetation cover measures, the runoff resistance coefficient of grassland and shrub land is obviously increased compared with bare land slope. The resistance coefficients of grassland and shrub slope were 5.58 ~ 7.45 times and 5.61 ~ 6.26 times than those of bare land respectively. The average drag coefficient of slope under different conditions is closely related to the rainfall intensity, and decreases with the increase of rainfall intensity. At the same time, the drag coefficient of slope flow is affected by both the rainfall intensity and the development pattern of underlying surface conditions. The formulas for calculating the composite nonlinear resistance coefficients of different slopes are established. The coefficient of variation shows that grass cover and rainfall intensity have a decisive influence on the flow resistance of slope. The research is of scientific significance to reveal the mechanism of runoff and sediment production by vegetation control and provide a scientific basis for ecological restoration engineering construction.