基于水力模型的城市排水干渠排涝流量计算方法

Calculation of Drainage Flow Rate of Urban Drainage Channels Based on Hydraulic Model

针对城市排水干渠既承接上游山区洪水,又沿途接纳城市雨水管道涝水的特性,以湖北省黄石市某排水干渠为例,提出了城市干渠排涝流量计算模型。模型将城市干渠汇水区域划分为山地子排区和城市子排区,在子排区层面分别利用单位线法(山区)和MIKE SWMM模型(城区)建立暴雨径流模型,然后在共同的排水通道(城市干渠)层面建立了MIKE11水动力学模型。该模型既考虑了山洪以沟渠为主要排水方式的特点,又考虑了城区涝水以雨水管网为主要排水方式的特点,同时可以模拟排水干渠下游受顶托的情况。相对于传统的单位线法,水力模型法计算的径流总量大、峰值流量小、峰现时间早。该研究可为城市排水干渠排涝流量计算方法的选择及其合理取值提供参考。

rural mountain According to the characteristics of urban drainage channels, which receive flood from areas and waterlogging from urbanized areas, a computing model of drainage flow rate of urban drainage channels was buih by taking an urban drainage channel in Huangshi of Hubei Province as an example. In the model, the catchment was divided into two sub-drainage areas, namely urbanized are- as and rural mountain areas, which adopted MIKE SWMM and unit hydrograph method respectively to es- tablish rainfall-runoff models. On the layer of their shared drainage channels, a river networks dynamic model was established by MIKE11. This model considers the difference of rainfall-runoff process for ur- banized areas and rural mountain areas where stormwater is collected by drainage pipe network and small ditches respectively, and can simulate the process of water stage and discharge for urban drainage channel under the influence of tidal backwater. Compared with traditional unit hydrograph method, this model can conclude lager volume of surface runoff, lower peak flow and the appearance of peak flow in advance. The results of this study may provide a reference for computing drainage flow rate and help determine a reasonable value of drainage flow rate for drainage engineering design.