桥墩密布的城市河道壅水高度及防洪对策研究

发布时间：2018-06-26 20:25

本文选题：串列桥墩 + 尾流亏损　；参考：《中国海洋大学》2014年硕士论文

【摘要】：随着沿河快速路的修建，使得越来越多的城市河道主槽内或一侧均修建了顺水流连续分布的桥墩，严重挤压了河道的行洪断面，造成较大壅水和流速分布的不均匀化，这势必对河道行洪与河岸防护造成严重威胁。国内外众多学者对单个桥墩和双圆柱周围水流结构和圆柱绕流现象有着较为深入和全面的研究；在桥墩壅水方面，前人研究的内容主要围绕正交桥墩和斜交桥墩进行。然而，但对于串列桥墩尾流现象及其产生的壅水，尤其是城市河道带状串列桥墩引起的流速亏损和壅水计算，目前尚无计算公式和科学合理的评判方法，更无相应的技术控制标准，尚属空白。本文在前人研究的基础上，对串列桥墩尾流及壅水问题进行了比较系统的研究，在理论分析、物理模型试验以及数值模拟方面开展了新的探索。在理论研究方面，推导基于尾流尾涡叠加原理的串列桥墩尾流沿程最大亏损流速公式及尾流区横断面流速亏损公式，并建立满足工程计算精度的壅水高度半经验半理论公式；在物理模型试验方面，利用ADV流速仪和水位测针测得不同工况下串列桥墩尾流流速分布及墩前壅水高度；在数值模拟方面，利用CFD软件FLOW-3D建立了串列桥墩的三维水动力数学模型，探讨了串列桥墩绕流流态的变化规律，分析墩后尾流流场分布及墩前壅水高度，并利用模型试验结果进行了验证，结果吻合良好。针对上述研究结果，本文提出桥墩密布城市河道的防洪对策：在保证工程合理性和安全性的基础上，应尽可能缩小桥墩间距，并减少建于河道中的桥墩数量和桥墩直径，对于洪水期来流流速增大而导致的墩前冲高变大，应当充分考虑桥墩受冲高影响的受力情况，增加墩身强度和保护。
[Abstract]:With the construction of the expressway along the river, more and more piers with continuous distribution of water flow are built in the main channel or one side of the urban river channel, which seriously compresses the flood discharge section of the river, resulting in a large backwater and uneven velocity distribution. This is bound to be a serious threat to river flood discharge and river bank protection. Many scholars at home and abroad have a deep and comprehensive study on the flow structure and flow around a single pier and a double cylinder. In the backwater of piers, the previous studies mainly focus on orthogonal piers and skew piers. However, for the wake phenomenon of tandem piers and the backwater produced by them, especially for the velocity loss and backwater calculation caused by strip piers in urban river channels, there is no calculation formula and scientific and reasonable evaluation method at present. There is no corresponding technical control standard, which is still blank. On the basis of previous studies, this paper makes a comparative and systematic study on the wake and backwater problems of tandem piers, and makes a new exploration in theoretical analysis, physical model test and numerical simulation. Based on the theory of wake superposition, the formula of maximum loss velocity along wake and cross-section velocity loss in wake region of tandem bridge pier is derived, and the semi-empirical and semi-theoretical formula of backwater height is established to meet the engineering calculation accuracy. In physical model test, ADV velocimeter and water level needle are used to measure the velocity distribution of wake flow and the backwater height in front of the piers under different working conditions, and in the aspect of numerical simulation, Using CFD software FLOW-3D, the three-dimensional hydrodynamic mathematical model of serial piers is established, and the variation law of flow state around serial piers is discussed. The distribution of flow field at the rear end of piers and the backwater height in front of the piers are analyzed, and the results of model tests are used to verify this model. The results are in good agreement. In view of the above research results, this paper puts forward the flood control countermeasures for the urban river course with dense piers: on the basis of ensuring the rationality and safety of the project, the distance between the piers should be reduced as far as possible, and the number of piers and the diameter of the piers built in the river should be reduced. When the flow velocity increases during flood period, the pier's forward impact height should be increased, and the strength and protection of pier body should be increased by taking full account of the force of pier affected by the impact of scour height.
【学位授予单位】：中国海洋大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TV87;U442.3

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