基于SWMM的北京市核心区合流制排水管网清淤方案研究

Research on desilting scheme of combined drainage network in Beijing Core Area based on SWMM

管道沉积物淤积会影响城市管网排水能力,每年汛前对排水管网开展清淤是北京市内涝防治的重要工作之一。但由于北京市核心区街道狭窄,清淤施工作业条件差,工作效率低,并且多数管道达不到设计标准要求,导致每年淤积管道数量较大,汛前完成所有管道清淤工作难度高,因此如何确定区域内重点清淤管道,快速恢复管网排水能力,对指导北京市核心区排水管网清淤工作十分重要。以北京市核心区某合流区域排水管网为研究对象,基于SWMM模型,从管网淤积风险判断、不同淤积程度的清淤必要性判断以及重点清淤管段选择标准3方面研究。结果表明:在管网整体40%的淤积情况下,暴雨重现期不超过5年时,对总长度25.2%的重点管道进行清淤后,溢流节点数量恢复至无淤积工况,节点最大溢流时间、排口总出流量、排口峰值流量变化值是全部管段清淤变化值的85.0%、76.0%、69.5%以上,表明对重点管道清淤方法可较大范围恢复区域排水能力。

Sediment accumulation in pipelines can have a detrimental impact on the drainage capacity of urban pipeline networks.Every year,one of the crucial tasks in flood prevention and control in Beijing is to conduct dredging of the drainage pipeline network prior to the flood season.However,due to the narrow streets in the core area of Beijing,inadequate working conditions for dredging operations,and non-compliance of most pipelines with design standards,a significant number of pipelines accumulate sediment annually.Completing all dredging work before the flood season poses a challenge.Therefore,determining the key dredging pipelines in the area and promptly restoring the drainage capacity of the pipeline network is essential to guide the dredging work of the drainage pipeline network in the core area of Beijing.This article focuses on the drainage pipeline network in a confluence area of the core of Beijing.Based on the Storm Water Management Model(SWMM),this study examines pipeline sedimentation risk assessment,the necessity of dredging at different sedimentation levels,and key pipeline selection criteria for dredging.The results reveal that in a scenario where 40%sedimentation exists in the entire pipeline network and the recurrence interval of heavy rainfall does not exceed five years,dredging 25.2%of the total length of key pipelines is sufficient to restore overflow node numbers to a non-sedimentation state.The maximum overflow time of the nodes,the total outflow of the discharge port,and the change in peak discharge value of the discharge port are more than 85.0%,76.0%,and 69.5%,respectively,of the total dredging changes of all pipeline segments.This indicates that the key pipeline dredging method can significantly restore the drainage capacity of the area over a broad range.Overall,the findings of this study highlight the importance of identifying and prioritizing key pipelines for dredging in the core area of Beijing,thereby facilitating a timely response to restore the drainage capacity of the pipeline network.