模拟降雨条件下崩积体坡面产流产沙特征及其响应关系

[目的]研究崩积体坡面产流产沙特征及其响应关系,为崩岗治理提供理论基础与科学依据。[方法]通过室内模拟降雨试验,探讨不同覆盖度(0%,25%,50%,75%,100%)和坡度(25°,30°,35°)组合坡面在90mm/h雨强条件下的产流产沙时空特征及其响应关系。[结果]不同覆盖度和坡度条件下,坡面产流时间的变化范围在33~292s;同一坡度条件下,坡面产流时间与覆盖度呈线性正相关关系;同一覆盖度条件下,坡面产流时间与坡度呈幂函数关系。通过双因素方差分析可知,坡度对径流量的影响达到极显著水平,覆盖度对产沙量的影响达到显著水平。当坡度为25°时,坡面产沙总量的临界覆盖度为50%;当坡度为30°时,坡面产沙总量的临界覆盖度为75%;当坡度为35°时,坡面径流量的临界覆盖度为50%。[结论]针对不同坡度崩积体坡面,可以选择合适的秸秆覆盖度以达到较好的水土保持效果。

Processes and Responses of Runoff and Sediment Yield on Colluvial Deposits Under Simulated Rainfall

[Objective] The erosion mechanism of colluvial deposits was researched to provide a theoretical basis and scientific evidence for the treatment of collapsing hills.[Methods] An indoor rainfall simulation experiment on slopes of colluvial deposits under 90 mm/h rainfall,and with the treatments of coverages(0,25%,50%,75%,100%) and slopes(25°,30°,35°) was carried out. Runoff and sediment were measured.[Results] The initiating time of runoff under different conditions changed from 33 to 292 s. Under the same slope gradient, there was a linear positive correlation between the initiating time of runoff and the straw coverage, and the initiating time of runoff had a power function with slope as independent variable. Through two-way variance analysis, the influence of slope on runoff was very significant and the influence of coverage on sediment yield was significant. The critical straw coverage of sediment yield was 50% under 25°, the critical straw coverage of sediment yield was 75% under 30°, the critical straw coverage of runoff was 50% under 35°.[Conclusion] For different slope gradients of colluvial deposits,we can choose optimal coverage of straw to reduce sediment yield and runoff effectively.