区域特征参数及降雨等级差异性对合流制系统溢流影响模拟研究

Simulation study on the influence of regional characteristic parameter and rainfall grade difference of combined sewer overflow

针对地形坡度、土壤渗透性能、不透水面积率、年径流总量控制率、截流倍数、截流井上游管段设计重现期六类合流制区域特征参数及降雨因素对合流制溢流总量及溢流频次的影响,利用SWMM模型模拟研究了合流制区域特征参数对溢流结果的影响权重、合流制区域特征参数组合正交方案的差异性及降雨因素与引入的溢流比概念的响应关系。结果表明,合流制区域特征参数针对不同的溢流评价指标,在场次降雨与雨季连续降雨边界条件下对溢流结果的影响权重排序不同;不同合流制区域特征参数组合工况条件下,源头体积控制可对溢流总量削减12.01%~100%,对溢流频次可削减0~6次;年溢流比与年降雨量关联性较强,年溢流比高的年份为特丰水年或偏丰水年;对于场次降雨来说,当降雨等级为大到暴雨及以上等级易产生溢流,场次溢流比随降雨等级增加而增加。

According to the effect of six types of combined sewer system regional characteristic parameters including terrain slope,soil permeability,impervious ratio,capture ratio of annual rainfall runoff volume,interception ratio,interception well upstream pipe network design return period and rainfall factors on combined sewer overflow(CSO)volume and frequency.SWMM is used to simulate and study the influence weights of the combined regional characteristic parameters on the CSO,the difference of the combined orthogonal schemes of combined regional characteristic parameters,and the response relationship between rainfall factors and the introduced concept of the overflow ratio.The results show that the influence weight ranking of combined sewer system parameters on overflow is different for different overflow evaluation indicators and different rainfall data;Under different combined system parameters combination conditions,under the different total annual runoff control rate,the total overflow can be reduced by 12.01%~100%,and the overflow frequency can be reduced by 0~6 times;The annual overflow ratio has a strong correlation with the annual rainfall,and the annual overflow ratio is high under the especially abundant water year and the wet year;For a rainfall event,when the rainfall level is large to heavy rain and above,it is easy to cause overflow,and the session overflow ratio of the event increases with the increase of the rainfall level.