城区涉河工程协同建设对河道行洪影响研究

Research on Impact of Coordinated Construction of River-related Engineering on River Flood Discharge in Urban Areas

摘要:

为研究城区开发中涉河工程修建对上游河道行洪功能的影响，采用HEC-RAS模型模拟某城区整治河道下游修建水库前后及市政桥梁建设前后河段水力要素，分析不同重现期下建桥断面的水力要素变化规律。结果表明：水库建设后，对库区建桥断面的水位流速影响较大，库区水位雍高流速降低，但对库区末端上游河道断面几乎无影响。相对于未建库的原河道，由于水库建设后库区水力要素稳定，由建设桥梁引起的水位、流速及阻水比变化更小。对城市开发区水库与及市政桥梁协同建设的洪水影响进行分析，提出城市大规模开发区涉河洪水影响评价建议，以研究规律及为类似项目防洪综合评价提供参考。

Abstract:

In order to study the impact of river-related engineering construction on the flood discharge capacity of upstream river channels during urban development, the HEC-RAS model is used to simulate the hydraulic elements of the river section in an urban area before and after the construction of a reservoir in the lower reaches of the river and before and after the construction of municipal bridges. The variations in hydraulic elements at the bridge cross-section under different return periods are analyzed. The results indicate that after the reservoir construction, the water level and flow velocity at the bridge cross-section within the reservoir area are significantly affected, and the water level in the reservoir area has risen sharply and the flow rate has decreased. However, there is almost no impact on the upstream section of the river at the end of the reservoir area. Compared with the original river channel without the reservoir, the hydraulic elements in the reservoir area become more stable after the reservoir construction, and the changes in water level, flow velocity and water-blocking ratio caused by bridge construction are smaller. The flood impact of coordinated construction of reservoirs and municipal bridges in urban development areas is analyzed. The suggestions for the impact assessment of floods related to rivers in large-scale urban development areas are proposed, which provide a reference for flood control comprehensive evaluations in similar projects.