暴雨下川东黄壤区不同径流路径调控措施对坡面侵蚀特征的影响

为研究川东区不同径流路径调控措施对黄壤坡面侵蚀特征的影响,设置3种坡度(25°,30°,35°)的稀疏型菱形网格(R1)、密集型菱形网格(R^2)和对照(R0)的裸坡坡面,基于人工模拟降雨试验,对比分析3种降雨强度(60,90,120 mm/h)下坡面的侵蚀过程与特征。结果表明:(1)相同坡度下,2种处理和对照组坡面在60,90 mm/h的雨强下初始产流耗时表现为R0R1>R^2,当坡度增大至35°和雨强增大至120 mm/h时,R1、R^2坡面的产流产沙速率逐渐接近甚至有稍微超过R0坡面的趋势。(4)与产流产沙过程相对应,R1、R^2坡面在不同坡度和降雨强度组合中,通常减沙效益大于减流效益,累积产沙量与累积径流量均成幂函数关系。研究结果可为揭示川东黄壤区坡面的侵蚀过程研究提供参考,为该区域的水土流失治理提供科学依据。

Influence of Different Runoff Path Regulation Measures on Slope Erosion Characteristics Under Rainstorm in the Yellow Soil Area of East Sichuan

In order to study the influence of different runoff path regulation measures on the erosion characteristics of yellow soil slope in the east of Sichuan Province, three kinds of bare slope (25°, 30° and 35°, respectively) with sparse diamond grid (R1), dense diamond grid (R2) and contrast (R0) were set up. Based on the simulated rainstorm experiment, the erosion process and characteristics of slope surface under three rainfall intensities (60, 90 and 120 mm/h) were compared and analyzed. The results showed that: (1) On the slopes with the same gradient, under the rainfall intensities of 60 mm/h and 90 mm/h, the initial runoff production time followed the order of R0 < R1 < R2, when the rainfall intensity increased to 120 mm/h, the initial runoff production time was R0 < R2 < R1. (2) The runoff increased rapidly at first and then tended to be stable during the process of runoff production, the sediment yield rate decreased with the increasing of runoff time. (3) When the slope gradient was small (25°) or the rainfall intensity was small (60 mm/h), the average runoff and sediment yield rates followed the order of R0 > R1 > R2. When the slope gradient increased to 35 ° and the rainfall intensity increased to 120 mm/h, the runoff and sediment yield rates of R1 and R2 gradually approached or even slightly exceed that of R0 slope. (4) Corresponding to the process of runoff and sediment yield, under the different slope and rainfall intensity combinations, the benefit of sediment reduction was generally greater than that of runoff reduction on R1 and R2 slope, and the relationship between cumulative sediment yield and cumulative runoff could be expressed in power function. The results could provide reference for revealing the slope erosion process in the yellow soil area of East Sichuan, and provide scientific basis for the control of soil and water loss in this area.