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植被覆盖对坡面流流速的影响,会引起坡面输沙特征的改变,但在陡坡条件下盖度与流速的响应关系尚不明确。针对目前国内外研究的不足,本研究采用变坡实验水槽在较大坡度(5°～25°)、流量(0.25～2 L/s)和盖度(0%～25%)范围内,系统研究了坡面流平均流速与盖度、坡度、流量之间的关系。结果表明:坡面流流速在0.15～1.35 m/s内变化,流速与盖度、坡度和流量关系密切。随着地表模拟盖度的增加,水流克服覆盖物的阻碍作用而消耗的能量越多,水流流速随之减小。随着坡度和流量的增加,坡面流重力势能与水流动能增加,因此流速随坡度和流量呈幂函数增加。通过统计回归发现,盖度对流速的影响最大,占45%左右,坡度和流量次之。三个因子可以较好模拟陡坡、定床条件下水流流速(R2=0.93)。研究结果有助于认识陡坡地表覆盖下坡面流的水动力学特性,为建立土壤侵蚀过程模型提供理论基础。
The influence of vegetation cover on the velocity of slope flow will lead to the change of sediment transport characteristics. However, the relationship between coverage and flow velocity is not clear under steep slope conditions. In view of the current domestic and foreign research deficiencies, this study adopted a variable slope experimental sink in the range of larger slope (5 ° ~ 25 °), flow (0.25 ~ 2 L / s) and coverage (0% ~ 25% The relationship between the average velocity of slope flow and the coverage, slope and flow rate was studied. The results show that the flow velocity of slope varies from 0.15 to 1.35 m / s, and the flow velocity is closely related to the coverage, slope and flow rate. As the simulated surface coverage increases, the more energy is consumed by the water flow to overcome the obstruction of the cover, the lower the water flow rate. With the increase of slope and flow rate, the gravity potential energy and water flow kinetic energy of slope flow increase, so the flow rate increases with the slope and flow rate as a power function. Through statistical regression, it is found that the coverage has the greatest impact on the flow rate, accounting for about 45%, followed by the slope and the flow. Three factors can simulate steep slopes, fixed bed flow velocity (R2 = 0.93). The results of this study are helpful to understand the hydrodynamic characteristics of slope flow under steep slope cover and provide a theoretical basis for establishing the soil erosion process model.