多源洪水耦合模型在防洪保护区洪水分析中的应用

Application of multi-source flood coupling model to flood analysis of flood protection zone

针对防洪保护区单一洪水风险分析的不足,以一、二维非恒定流基本控制方程为理论基础,采用有限体积法对网格进行离散求解,建立溃堤洪水和暴雨多源洪水耦合的数学模型。在一、二维模型的链接处选用堰流公式实现河槽与保护区水流的实时交互,借助干湿水深理论对模型进行优化,利用遥感影像解译处理保护区内复杂地形条件下糙率对洪水演进的影响,概化处理区域内道路和过水涵洞对洪水的阻水或导水作用,并利用历史实测洪水资料进行模型验证。将验证后的模型应用于淮河干流凤台段防洪保护区多源洪水运动耦合模拟,分析了单一洪水与多源洪水对防洪保护区的损失比较结果,说明该区域受暴雨内涝影响较为严重。

Aiming at the shortcomings of the single flood risk analysis in the flood protection zone,in this paper the one-dimensional and two-dimensional unsteady flow basic control equations are taken as a theoretical base for analysis of flood risk. In order to solve the discrete grid problem,the finite volume method（ FVM） is used for solving discrete grids. A multi-source coupling mathematical model for levee-breach flood and rainstorm has been established at the same time. The 1D and 2D models are jointed through a weir flow equation to calculate the realtime interaction between the river and the flood protection zone. It is optimized by dry depth and wet depth theories for the sake of making faster and better results. And this model has also utilized a remote sensing image interpretation method to deal with the complicated roughness having important impacts on the flood routing. And a generalized method is used to deal with the roads and water culverts which prevent or guide the flowing of water in the flood protection zone. This model is tested by historically measured flood data,which are the basic requirements in actual engineering simulation,and then the verified model is applied to simulate the multi-source flood occurring in the flood protection zone at Fengtai reach. Analysis of the big difference between the serious damages caused by a single flood and a multi-source flood is carried out. The research findings are of great significance in analyzing the multi-source flood and simulating flood motion coupling. And researchers can use the analysis results to make risk evaluation of the flood in the research area and also in some similar flood control protection areas.