桥梁建设对蓄滞洪区洪水演进影响的模拟与分析--以濛洼蓄洪区特大桥工程为例

Simulation and Analysis on Impact of Bridge Construction on Flood Evolution in a Flood Storage and Detention Area-Taking Mengwa Flood Storage Area Bridge Project as an Example

[目的]分析涉水建筑物修建前后洪水演进过程的影响,为真实高效计算桥梁工程对蓄滞洪区洪水演进过程以及对蓄洪区防洪工作的有效开展提供科学支持。[方法]选取安徽省阜阳市濛洼蓄洪区为研究区,利用区域地形、水文数据、桥梁工程设计等最新资料,采用MIKE 21的非结构化水动力学模型,将进洪退洪过程作为整体对濛洼蓄洪区洪水演进过程进行实时模拟,分析桥梁工程建设对蓄滞洪区洪水演进分洪时间、流速分布、水位变化等特性的影响。[结果]桥梁工程修建后,桥位附近分洪历时比工程修建前最大滞后45 s,主流区流速分布范围为0.4~0.6 m/s,局部流速变化率最大7.409%,桥墩附近水位最大抬高值为0.006 m,水位最大变化率为-0.22‰。[结论]桥梁的建设延缓了蓄洪区行洪时间,抬高了桥墩附近水位,改变了工程附近流速分布,但对蓄洪区整体的影响较小,基本不影响濛洼蓄洪区的正常运行。

[Objective]The influence of water-related structures on the flood routing process before and after structure construction was analyzed to provide scientific supports for the real and efficient calculation of bridge engineering in flood storage and detention areas,and for the effective development of flood control in flood storage areas.[Methods]The Mengwa flood storage area in Fuyang City,Anhui Province was selected as the study area.Based on the latest data of regional topography,hydrological data,and bridge engineering design,the unstructured hydrodynamic model of MIKE 21 was used to simulate the flood evolution process of the Mengwa flood storage area in real time.The influence of bridge construction on flood evolution time,velocity distribution,and water level change in the flood storage and detention area was analyzed.[Results]After the construction of the bridge project,the flood-splitting time near the bridge position was 45 s behind the maximum lag before the construction of the project;the flow rate distribution range of the mainstream area was 0.4 to 0.6 m/s;the local velocity change rate was 7.409%;the maximum elevation value of the water level near the bridge was 0.006 m;and the maximum change rate of the water level was-0.22‰.[Conclusion]Bridge construction delayed the flooding time in the flood storage area,raised the water level near the pier,and changed the distribution of the flow rate near the project.However,the overall impact on the flood storage area was small,and basically did not affect the normal operation of the flood storage area.