不同植被盖度对三峡库区边坡减蚀的室内模拟降雨研究

为探究气候和植被覆盖度变化对三峡库区消落带库岸边坡的影响，通过开展人工模拟降雨试验，分析不同雨强和植被覆盖度(0,30%,50%,70%,90%)下坡面侵蚀规律及变化特征。结果表明：(1)在不同雨强下，植被边坡侵蚀累计产沙量均随植被覆盖度的增加呈现下降趋势，整体下降演变的趋势可分为迅猛—平缓—稳定3个阶段，三峡库区消落带库岸边坡的临界盖度为50%～70%,维持植被覆盖度在此区间可以有效抑制坡面的泥沙损失。(2)同一植被覆盖度条件下地表径流相对系数与雨强呈正相关。同一雨强条件下地表径流相对系数与植被覆盖度呈负相关，说明坡面植被可以有效地阻滞地表径流，对水土流失具有一定的抑制作用。(3)选用Horton降雨入渗模型分析不同植被覆盖度对降雨入渗速率影响，发现不同植被覆盖下边坡降雨入渗大体分为降雨初期迅速减小，中期减小幅度变缓，后期逐渐趋于稳定3个阶段。植被覆盖度越大，稳定入渗率越高。研究成果可为三峡库区库岸边坡水土流失治理与推动长江生态环境保护修复提供理论参考。

Study on Indoor Simulated Rainfall with Different Vegetation Coverage on Slope Erosion Reduction in the Three Gorges Reservoir Area

In order to explore the influence of climate and vegetation coverage changes on the shore slope of the fading zone of the Three Gorges reservoir area, the erosion laws and changing characteristics of different rainfall intensity and the vegetation coverage (0, 30%, 50%, 70%, 90%) were analyzed with artificial simulated rainfall experiments. The results show that: (1) Under different rain intensities, the accumulated sediment yield of vegetation slope erosion shows a downward trend with the increase of vegetation coverage, and the overall downward evolution trend can be divided into three stages rapid-gentle-stable, and the critical coverage of the shore slope of the Three Gorges Reservoir Area in the fading zone is 50%~70%, and maintaining vegetation coverage in this interval can effectively inhibit the sediment loss on the slope. (2) The relative coefficient of surface runoff under the same vegetation cover is positively correlated with rain intensity. The relative coefficient of surface runoff under the same rain intensity is negatively correlated with the vegetation coverage. It indicates that the vegetation on the slope can effectively block the surface runoff and have a certain inhibitory effect on soil erosion. (3) The Horton rainfall infiltration model was selected to analyze the influence of different vegetation coverage on the infiltration rate of rainfall. The analysis suyyests that the infiltration of rainfall on the slopes under different vegetation cover was roughly divided into three stages rapid decrease in the early stage of rainfall, slowing down in the midterm, and gradual stabilization in the later stage. The greater the vegetation coverage, the higher the stable penetration rate. The research results can provide a theoretical reference for soil erosion control on the slopes of the Three Gorges Reservoir Area and for promoting the protection and restoration of the ecological environment of the Yangtze River.