黄土高原地区鱼鳞坑坡面侵蚀演化过程及水力学特征

发布时间：2018-05-16 10:24

  本文选题：鱼鳞坑坡面 + 间歇性降雨　； 参考：《土壤学报》2017年05期

【摘要】：为明确鱼鳞坑坡面抗侵蚀演化过程及其水流水力学特性,采用间歇性人工模拟降雨实验,对鱼鳞坑坡面水流水力学特性以及阻力规律进行了系统分析。结果表明:(1)鱼鳞坑坡面侵蚀演化过程表现为:雨滴溅蚀—片蚀—股流冲刷—跌坑—细沟侵蚀—下切侵蚀—溯源侵蚀—崩塌。(2)随着降雨历时的增加,由于鱼鳞坑的层层拦截与蓄满,其下方的坡面径流流速、水深均呈波动式增长趋势,坑内出现旋涡,坡面径流呈现断续股流。降雨累积历时为58 min左右,总降雨量达到87 mm时,鱼鳞坑侵蚀量急剧增加,拦蓄径流作用失效。(3)五场降雨过程中,上坡和中坡水流流态为层流,下坡由于鱼鳞坑蓄满后径流出现波动,水流流态由层流变为紊流且时而为缓流时而为急流。(4)鱼鳞坑坡面水流阻力来源于降雨阻力、颗粒阻力、形态阻力叠加,在整个降雨过程中阻力总和呈下降趋势;其中,受地形高低起伏、地表糙度的影响,形态阻力一直居于主导地位。
[Abstract]:In order to understand the evolution process of anti-erosion and the characteristics of water flow and hydraulics on the slope of the fish-scale pit, the hydraulic characteristics and the law of resistance of the water flow on the slope of the fish-scale pit were systematically analyzed by the intermittent artificial rainfall simulation experiment. The results show that the evolution process of the slope erosion in the fish-scale pit is as follows: raindrop splash erosion, sheet erosion, stream erosion, rill erosion, traceability erosion and collapse. 2) with the increase of rainfall duration, Because of the interception and accumulation of the fish scale pit, the flow velocity and depth of the slope below the pit are all increasing in a fluctuating trend, the vortex appears in the pit, and the runoff on the slope presents intermittent flow. When the cumulative duration of rainfall is about 58 min and the total rainfall reaches 87 mm, the erosion amount of the fishscale pit increases sharply, and the failure of the impounding runoff is. 3) during the five rainfall periods, the upper and middle slope water flow pattern is laminar flow. Due to the fluctuation of runoff after the fish scale pit is filled, the water flow state changes from laminar flow to turbulent flow, and sometimes to slow flow and then to jet flow. 4) the flow resistance on the slope of fish scale pit comes from rainfall resistance, particle resistance and morphological resistance superposition. During the whole process of rainfall, the total resistance showed a downward trend, among which, the morphological resistance was always dominant due to the influence of the topographic fluctuation and the roughness of the surface.
【作者单位】： 西北农林科技大学旱区农业水土工程教育部重点实验室;重庆市万盛经济技术开发区水务局;
【基金】：国家自然科学基金项目(41671276)资助~~
【分类号】：S157.1
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本文编号：1896473