基于SWMM模型的溢流口水文计算

Hydrological Calculation of Overflow Outlet Based on SWMM Model

该文基于SWMM模型,建立道路排水水文水动力模型,模拟分析了溢流口外排流量的时程变化,并计算出了不同设计降雨条件下的最大外排流量。同时,将模型预测值与传统水力学方法计算的最大外排流量进行比较,分析了差异以及导致差异的原因。结果显示:(1)根据传统水力学方法计算的最大外排流量大于模型模拟的最大外排流量,以侧分带溢流井最大外排流量为例,在不同设计年限下,前者平均为后者平均的1.62倍,用前者作为设计值,过于保守,增大了不必要的投资;(2)在重现期大于十年的设计降雨条件下,中分带会产生一定的地表径流,多数设计未考虑设置雨水系统,易导致超标雨水漫流进入车行道,具有一定安全隐患,应设置溢流设施,并根据中分带宽度、暴雨强度确定规模。

Based on the SWMM model,this paper established a hydrological and hydrodynamic model for road drainage to simulate and analyze the time-history change of the discharge flow from the overflow outlet,and calculated the maximum efflux flow under different design rainfall conditions.Meanwhile,this paper compared the maximum efflux flow predicted by the model with that calculated by the traditional hydraulic method,and analyzed the difference and the reasons for the difference.The results showed that(1)the maximum efflux flow calculated with the traditional hydraulic method is greater than that simulated by the model.Taking the maximum efflux flow rate of the overflow well in the side zoning as an example,under different design years,the average of the former is 1.62 times that of the latter.Using the former as the design value is too conservative and increases unnecessary investment;(2)under the designed rainfall conditions with a return period greater than ten years,a certain amount of surface runoff will be generated in the mid-zonal zone.Most designs do not consider setting up a rainwater system,which easily causes excessive rainwater to flow into the roadway,causinng safety hazards.So overflow facilities should be established,and the scale should be determined according to the width of the median belt and the intensity of rainstorms.