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黄土坡面细沟水流剪切力及其侵蚀效应研究
陆绍娟1,2, 王占礼1,2,3, 谭贞学4
1.西北农林科技大学水土保持研究所 陕西 杨凌 712100;2.黄土高原土壤侵蚀与旱地农业国家重点实验室 陕西 杨凌 712100;3.中国科学院水利部水土保持研究所 陕西 杨凌 712100;4.钦州市水土保持监测分站 广西 钦州 535000
摘要:
采用具有定流量人工放水的组合小区模拟降雨试验方法,对黄土坡面细沟水流剪切力及其侵蚀效应进行了试验研究。结果表明:(1)细沟水流切应力随径流历时的变化,各雨强条件均表现出增大趋势,可用线性方程很好地描述,增大速率在产流6min之后略有减小。(2)细沟水流切应力随径流历时的变化,不同坡度下也不断增大,可用直线方程进行描述,产流过程中变化趋势较为一致,其中两个大坡度下增加速率较小坡度下稍大,产流12min以后更大。(3)坡面细沟水流平均切应力随雨强增大而增大,可用对数方程描述。随坡度增加而迅速增大,可用幂函数方程描述。随雨强及坡度的变化可用二元幂函数方程描述。(4)不同雨强及坡度下,细沟侵蚀率随细沟水流切应力的增大而增大,可用线性方程描述。研究表明,细沟水流剪切力具有显著的侵蚀效应,是产生细沟侵蚀的重要水力学参数和水动力学根源。
关键词:  黄土坡面  细沟水流  切应力  组合小区
DOI:
分类号:
基金项目:国家自然科学基金项目“黄土坡面细沟侵蚀关键参数及其耦合关系试验研究”(41171227);国家自然科学基金项目“黄土坡面细沟侵蚀动力学过程组合小区试验研究”(40971172);中国科学院重点项目“近百年黄土高原侵蚀环境与水沙变化”(KZZD-EW-04-03)
Shear Stress of Rill Flow and Surface Erosion Effect on Loess Hillslope
LU Shao-juan1,2, WANG Zhan-li1,2,3, TAN Zhen-xue4
1.Institute of Soil and Water Conservation, Northwest A&F University Yangling Shaanxi 712100 China;2.State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau Yangling Shaanxi 712100 China;3.State Key Laboratory of Soil Erosion and Dryland Farming on Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Science and Ministry of Water Resources Yangling Shaanxi 712100 China;4.Qinzhou Sub-station of Soil and Water Conservation Monitoring Qinzhou Guangxi 535000 China
Abstract:
The flow shear stress involved in rill erosion process on loess hillslope and its effect were studied by multi-plot experiments under simulated rainfall with addition of steady inflow through the tops of the plot.The results showed that:(1)The rill flow shear stress increased along with time under different rainfall intensities and the relationship could be described well with a linear equation.The rate of increase was a little less in 6 min after than before.(2)Under different slopes,it increased basically in the same trend and an equation of the straight line could be used to describe the change.The rate of increase appeared difference when runoff began after 12 min.(3)The shear stress of average slope rill flow increased with rainfall intencity and rapidly increased with slope. Its relation to rainfall intensity could be described by a logarithmic equation;to slope,by a power function equation;and to both of the two factors,by a dual power function equation.(4)Under different rainfall intensity and slope,the rill erosion rate increased along with the rill flow shear stress and the relationship could be described well with a linear equation.The shear stress of rill flow,that had significant erosion effect,was one of the important hydraulic parameters and hydrodynamic source of rill erosion.
Key words:  loess hillslope  rill flow  shear stress  multi-plot