| 江恩惠,李军华,曹永涛,赵连军.黄河“揭河底”机理研究及室内模拟试验[J].水利学报,2010,41(2): |
| 黄河“揭河底”机理研究及室内模拟试验 |
| Research on mechanism of bottom tearing scour in Yellow River |
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| DOI： |
| 中文关键词: 揭河底 层理淤积 机理 物理图形 脉动压力 模型试验 |
| 英文关键词: bottom tearing scour sediment layering mechanism physical figure pulse stress simulation test |
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| 摘要点击次数: 3747 |
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| 中文摘要: |
| 在深入调研及广泛收集整理现有研究成果的基础上，剖析了黄河“揭河底”现象发生的过程和主要特征；扩展了“揭河底”现象的概念；揭示了黄土高原特有的水文特征、下垫面条件及产流产沙过程、水沙组成等是形成“揭河底”河段典型河床层理淤积结构的前提条件；细颗粒泥沙絮凝效应是层理淤积结构中“胶泥层（块）”形成的机理。指出具有一定结构强度的“胶泥层”是“揭河底”发生的首要条件，特殊的来水来沙条件为其提供了揭底冲刷的动力。在此基础上，构建了动态的“揭河底”物理图形，即胶泥块形成、逐渐淘刷、失稳揭出、翻出水面4个动态过程；揭示了胶泥块上下表面脉动压力波传播速度不同引起的瞬时上举力是“揭河底”现象发生的真正机理。首次开展了真正意义上的室内“揭河底”模拟试验，探索了“揭河底”试验模拟技术，印证了“揭河底”物理图形的正确性，为后续判别指标的研究奠定了基础，同时也为近距离观察“揭河底”现象、观测同步水力泥沙参数提供了条件。 |
| 英文摘要: |
| Based on surveys and existing study results， the process and main characteristics of bottom tearing scour phenomenon in Yellow River was analyzed. The definition of this phenomenon was expanded.It is found that the specific hydrological characteristics， underlying surface conditions， process of runoff and sediment，and the composition of water and sediment in the loess plateau result in the formation of a special mud layer on river bed. Under the action of special runoff and sediment conditions this mud layer causes the appearance of bottom tearing scour. Model test in laboratory for simulating this phenomenon shows that the whole process of the bottom tearing scour can be divided into four stages：formation of mud layer， erosion， failure of stability and turning over of mud layer. The impetus that produces the phenomenon is the uplifting force acting on the mud layer due to the difference of fluctuating pressure. |
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