黄土细沟流跌坑的形成与作用机理

发布时间：2018-06-22 18:22

本文选题：跌坑 + 阶梯-深潭　；参考：《四川大学学报(工程科学版)》2016年05期

【摘要】：跌坑是细沟侵蚀过程中形成的一种床面形态,其是床面形态和水流流动相互作用的结果。借鉴下切型阶梯-深潭理论采用6种坡度(2°、4°、6°、8°、10°、12°),5种流量(8、16、24、32、40 L/min)完全组合冲刷试验,系统研究了黄土坡面细沟流跌坑形态发育过程及动力特性。结果表明:跌坑平均深度随坡度的增加而增加,跌坑平均间距与跌坑平均深度的比值随坡度的增加而减小,表明跌坑随坡度的增加发育越加成熟,且流量对两者影响均较少;跌坑发育系数随坡度的增加而增大,其值介于1.01和1.14之间,与细沟阻力系数呈正势变化,表明随着跌坑发育越显著,水流阻力越大,能量耗散越剧烈。相同坡度下,跌坑消能率随流量的增加呈线性减小趋势;而消能率随坡度和跌坑发育系数的增加呈幂函数增加关系,消能率范围在87.28%~98.58%之间,研究结果表明跌坑的发育及作用机制对细沟流流动特性及侵蚀产沙具有重要作用。
[Abstract]:The crater is a bed form formed in the process of rill erosion, which is the result of the interaction between the bed surface and the flow of water. Using the theory of down-cut ladder and deep pool for reference, six kinds of slope (2 掳~ 4 掳~ 6 掳~ 6 掳~ 8 掳~ 10 掳~ 10 掳~ (12 掳) and five kinds of flow rate (8 ~ 16 ~ 24 ~ (24) ~ 32 ~ 40 L ~ (-1) L / min) combined scour tests were used to study systematically the shape development process and dynamic characteristics of rill flow crater on loess slope. The results show that the average depth of the crater increases with the increase of the slope, and the ratio of the average spacing of the crater to the average depth of the crater decreases with the increase of the slope, which indicates that the crater grows more mature with the increase of the slope, and the effect of discharge on both of them is less. The development coefficient of the crater increases with the increase of the slope, and its value is between 1.01 and 1.14, which has a positive change with the resistance coefficient of the rill, which indicates that with the development of the crater, the greater the resistance of the flow, the more the energy dissipation. Under the same slope, the energy dissipation rate of crater decreases linearly with the increase of flow rate, while the energy dissipation rate increases with the increase of slope and the development coefficient of crater by power function, and the energy dissipation rate ranges from 87.28% to 98.58%. The results show that the development and mechanism of the crater play an important role in the flow characteristics of the rill flow and the erosion and sediment yield.
【作者单位】：西北农林科技大学水利与建筑工程学院;中国电建集团华东勘测设计研究院有限公司;中国科学院水利部水土保持研究所黄土高原土壤侵蚀与旱地农业国家重点实验室;清华大学水沙科学与水利水电工程国家重点实验室;
【基金】：国家自然科学基金资助项目(51579214;51209222;41001159) 国家重点基础研究发展计划资助项目(2015CB040441) 黄土高原土壤侵蚀与旱地农业国家重点实验室开放基金资助项目(A314021402-1619) 流域水循环模拟与调控国家重点实验室开放基金资助项目(IWHR-SKL-2014) 中央高校基本科研业务费专项资金资助项目(Z109021564)
【分类号】：S157.1

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