基于SWMM模型自动建模的桥梁排水系统模拟与优化

Drainage Simulation and Optimization on Bridge Runoff based on Automatic Modeling of SWMM

桥面雨水若不能及时排走,会对行车安全造成极大隐患。利用模型定量研究桥面径流汇水规律,分析确定影响桥面径流量变化的关键因素对于科学制订桥梁排水策略具有极为重要的意义。基于此,提出了针对公路桥梁排水系统的快速自动建模方法,以我国西北城市西安市为例,对当地的典型桥梁径流量变化规律及其关键影响因素进行了模拟分析。结果表明,桥面径流量大小主要受桥面面积、降雨重现期、降雨历时的影响,随三者增加而增大,而桥面纵坡对其影响相对较小。对于桥梁纵向排水管管径的确定,首次提出结合模型模拟计算管道流速和管内水深变化进行综合判定的思路,并与传统公式法对比。模拟探究了桥面汇流宽度对桥面典型径流污染物浓度变化的影响,当桥面汇流宽度较大时,更有利于径流污染物及时排走。研究成果可为公路桥梁排水系统优化设计和桥面径流污染物防控提供技术与数据支持。

If the rainwater on the bridge deck cannot be drained in time,it will cause great hidden danger to the driving safety.It is of great significance for scientific formulation of bridge drainage strategy by quantitatively studying on the law of bridge deck runoff and analyzing the key factors that affect the bridge deck runoff process through numerical model.Based on this,a fast automatic modeling method for highway bridge drainage system is proposed.Taking Xi'an of Shanxi Province as an example,the typical bridge runoff variation processes and the key influencing factors are simulated and analyzed.The results show that the bridge deck runoff is mainly affected by the bridge deck area,rainfall recurrence period and rainfall duration,and increases by them,while the longitudinal slope of the bridge deck has relatively little impact on it.To comprehensively determine the best diameter of longitudinal drainage pipes of the bridge,the idea of combining the model simulation to calculate the flow velocity and water depth change in the pipe is proposed for the first time,which is compared with the traditional formula method.The influence of the bridge deck overland flow width on the concentration change of typical runoff pollutants is simulated.When the width is large,it is more conducive to timely discharge of runoff pollutants.The research results can provide technical and data support for the optimal design of highway bridge drainage system and the prevention and control of bridge deck runoff pollutants.