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潮波流作用区低滩促淤方案分析与实践

张丽芬   

  • 出版日期:2019-10-28 发布日期:2019-10-28

Analysis and practice of siltation promotion scheme for low tidal flat in tidal zone

ZHANG Lifen   

  • Online:2019-10-28 Published:2019-10-28

摘要: 为顺利实施长江口南汇边滩大型低滩促淤工程,对上下游总计162 km2的3个自然促淤分区,根据不同地理位置、不同水沙特性,采用二维潮流数学模型等对河势滩势演变进行了分析。从促淤堤与圈围堤的结合方式、促淤分隔及促淤分期的淤积效果和经济性等方面系统分析了促淤工程总体方案的优劣,提出将促淤堤作为圈围堤稳定的镇压结构,兼作保滩结构等经济实用的促淤方案,实现河势控制先导、低成本多获泥沙资源及加快滩涂湿地形成等多重效益。同时对先行实施的复杂流场区促淤工程,研究了在不同实施顺序下促淤区内各堤段的水动力条件的变化情况,提出了先顺堤后侧隔堤、先深槽段后浅滩,且下游侧堤始终优先于其他侧隔堤的实施方案。实践证明上述促淤方案实施效果较好,实际淤积结果与计算结果相近。相关分析方法与经验可为类似工程提供借鉴。

关键词: 促淤堤布置, 促淤分隔, 促淤分期, 二维潮流数学模型, 南汇东滩, 长江口

Abstract: To smoothly implement the large scale siltation promotion project of Nanhui side low tidal flat, in the light of the geological location, flow and sediment characteristics of 3 natural siltation promotion areas of 162 km2, the 2 D mathematical model was employed to analyze the general scheme of siltation promotion from the respects of the combination way of siltation promotion dyke and cofferdam, the siltation effect of separation siltation promotion and staged siltation promotion as well as economy. According the analysis results, we use the siltation-promoting dykes that stabilize the enclosure cofferdam and also act as tidal flat protection structure to realize river regime guiding and control, more deposition with low cost and speed up the tidal flat formation. In the same time, the siltation-promotion project implemented in advance in complicated flow field was researched in the aspects of flow dynamic change of various dyke sections under different siltation sequence. We suggest a scheme of first training dyke, then lateral separation dyke, first deep channel then shallow, first downstream separation dykes then the other lateral separation dykes. The practice showed that the siltation promotion scheme was good in implementation, the practical siltation was similar with the computation result. The correlative analysis method and experience can provide reference for the similar project.

Key words: layout of siltation siltation promotion dyke, siltation promotion and separation, staged siltation promotion, Nanhui east beach, Yangtze River Estuary