长江中下游砂卵石分汊河段演变机理

发布时间：2018-11-10 11:30

【摘要】：受水动力条件、边界条件等影响,砂卵石分汊河段河床演变规律较为复杂.以长江中下游关洲-芦家河河段为例,分析了典型砂卵石弯曲分汊河段的演变特点.在此基础上,结合三峡蓄水后来水来沙、水动力轴线、泥沙粒径等河段变化特点,研究砂卵石分汊河段演变机理,并分析了砂卵石分汊河段的演变趋势.研究结果表明:自然情况下砂卵石分汊河段水沙输移主要特点为主流线随来流变化在两汊间摆动.在清水下泄河段总体冲刷背景下,河段冲刷主要以沙质河床部分为主,局部区域的淤积主要为推移质的淤积.蓄水后,关洲左汊将继续冲刷发展,芦家河水道沙泓进口淤积将有所发展,石泓的冲刷发展将相对较大,江心碛坝头部还将发生一定幅度的冲刷.
[Abstract]:Influenced by hydrodynamic conditions and boundary conditions, the evolution law of sandy pebble braided reach is more complex. Taking the Guanzhou-Lujiahe reach in the middle and lower reaches of the Yangtze River as an example, the evolution characteristics of the typical sand and gravel bend branching section are analyzed. On this basis, the evolution mechanism of the sandy pebble branching section is studied, and the evolution trend of the sandy pebble braided section is analyzed according to the characteristics of the water and sediment coming from the three Gorges Reservoir, the hydrodynamic axis and the sediment particle size. The results show that the main characteristics of the water and sediment transport in the sandy pebble branching reach are that the main flow line oscillates with the incoming flow between the two branches. Under the background of the general scour of the river reach with clear water, the main scour of the reach is the part of sandy riverbed, and the deposition of local area is mainly the deposition of bed load. After impounding, the left branch of Guanzhou will continue to scour and develop, the siltation of Lujiahe river channel will be developed, the scour development of Shihong will be relatively large, and the head of the moraine dam in the heart of the river will also be scoured to a certain extent.
【作者单位】：长江航道规划设计研究院;
【基金】：国家重点研发项目(编号:2016YFC0402105)
【分类号】：TV147

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