| 摘要: |
| [目的]定量评价坡面上方汇水对坡下方土壤侵蚀方式演变及侵蚀产沙的影响.[方法]利用由位于坡面上部的供水装置和位于坡面下部的试验土槽组成的试验系统,通过人工模拟降雨试验,分析不同降雨强度和坡度条件下,上方汇水对黄土坡面片蚀一细沟侵蚀一切沟侵蚀方式演变过程及侵蚀产沙量的影响.[结果]当坡面接受上方汇水后,各侵蚀方式演变速度明显加快,侵蚀产沙量迅速增大,且坡面侵蚀产沙增加幅度随上方汇水流量的增加而增大;在坡度和降雨强度相同条件下,坡面侵蚀产沙量和上方汇水引起的坡下方的净侵蚀产沙量,均随坡面上方汇水流量的增加而显著增大;受降雨强度、坡度和坡面侵蚀发育不同阶段的影响,坡面汇水引起的净侵蚀产沙量占总侵蚀产沙量的15.36%～78.15%.不同降雨强度和坡度条件下,坡面侵蚀产沙量与上方汇水流量呈幂函数关系.[结论]坡面上方汇水强度对坡面侵蚀方式演变和产沙过程具有重要影响,若能有效控制坡面上方汇水,将可有效减少坡面侵蚀产沙量,抑制沟蚀的发生和发展. |
| 关键词: 上方汇水；侵蚀产沙作用；侵蚀方式演变；模拟降雨 黄土坡面 |
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| 基金项目:国家重点基础研究发展计划项目(2007CB407201)；国家自然科学基金重点项目(40335050) |
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| Effects of upslope runoff on loessial hillslope erosion pattern evolution process and erosion sediment |
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| Abstract: |
| 【Objective】 The research is to quantify the effects of upslope runoff on loessial hillslope erosion pattern evolution process and erosion sediment.【Method】 An experimental equipment,consisting of a water feed installation and a test box,is used to quantify a contribution of upslope runoff to hillslope erosion and sediment during erosion pattern evolution processes from sheet erosion to rill,and then to gully at different rainfall intensities and slope gradients by using simulated rainfall. 【Result】 The results show that upslope runoff discharging into downslope section greatly quickens the speed of erosion pattern evolution and largely increases hillslope sediment yield. Meanwhile,hillslope erosion and sediment process correspond to erosion pattern evolution process.At the same rainfall intensity and slope gradient,hillslope sediment yield and the net sediment delivery caused by upslope runoff obviously increases as the upslope runoff rate increases.The net sediment deliveries caused by upslope runoff account for 15.39% to 67.87% of the total sediment delivery,which is affected by rainfall intensity,slope gradient,erosion pattern evolution process.The relationship between hillslope sediment yield and the upslope runoff rate is expressed as exponential function. 【Conclusion】 Upslope runoff rate has great influences on erosion pattern evolution and the sediment yield process of loessial hillslope |
| Key words: upslope runoff erosion and sediment contribution erosion pattern evolution simulated rainfall loessial hillslope |
