考虑双层排水系统的城市地下排水管网能力评估

Capacity Evaluation of Urban Drainage Network Considering Dual-layer Drainage System

城市雨洪管理模型SWMM最新的5.2版本采用了考虑排水管网和道路的双层排水思想,使城市雨洪模拟与实际情况更为接近。为了分析该版本与以往版本的差异,以广州市东濠涌流域为研究对象,分别构建双层排水系统模型和仅考虑地下排水管网的模型,模拟设计暴雨重现期分别为5 a、10 a、20 a、50 a、100 a情景下的洪涝过程。结果表明,随着设计暴雨重现期增大,两个模型的管道超载个数、节点超载数及节点积水个数也随之增多;在同一重现期暴雨情景下,双层排水系统模型的地下管网承载力比仅考虑地下管网的模型相对较高。将实测内涝点与双层排水系统模型模拟得出的内涝点进行对比,得出模型对于淹没深度较大的内涝点识别情况较好,但对淹没深度较小的内涝点识别情况一般,且对范围和水深的模拟有局限性。

The latest version(5.2)of urban flood management model(SWMM)adopts the idea of dual-layer drainage considering both drainage network and road system,which improves simulation accuracy of urban stormwater management practices.In order to analyze the difference between this version and the previous one,taking the Donghaochong watershed in Guangzhou as the research area,a dual-layer drainage system model and a model considering only underground drainage are constructed respectively.The models were simulated under various design rainfall return periods,including 5-year,10-year,20-year,50-year,and 100-year scenarios,to investigate the flood processes.The results show that with the increase of the return period of the designed rainfall,the number of conduit surcharge,node surcharge and node flooding of the two models also increase.Moreover,under the same rainfall scenario and return period,the bear capacity of the underground drainage of the dual-layer drainage system model is relatively higher than that of the model which only considers the underground drainage.Also a comparative analysis was conducted between the measured locations of inundation and the inundation locations identified through simulation using the dual-layer drainage system model.The findings indicate that the model excelled in identifying inundation points with substantial flood depths,but displayed limitations in identifying points with shallow flood depths.Overall,the model had limitations in accurately simulating the spatial extent and water depths associated with inundation events.