基于失效概率的雨水管网高风险管道识别与改造

Identification and rehabilitation of high-risk pipes in stormwater networks based on failure probability

识别高风险管道并降低其失效概率是缓解城市内涝积水的重要手段。为此,提出了一种基于排水能力-失效概率相关关系的高风险管道判别方法:首先以充满度等于1为管道失效的临界判别条件,并基于蒙特卡洛抽样计算管道在设计降雨情景下的失效概率;其次采用SWMM评估管道的排水能力;然后利用K-means聚类算法和分段回归分析法构建管道排水能力与失效概率的相关关系,并借助该相关关系推求出高风险管道的判别阈值,以北京市丰台区排涝片区为例,在3 a一遇降雨情景下,推求出失效概率等于3.64%为高风险管道的判别阈值;并结合高风险管道的纵断面图进行内涝成因分析,制定改造方案。模拟结果表明:改造后高风险管道数量占雨水管道总数的比例由91.39%降低至2.32%;高风险管道总长度占雨水管网总长度的比例由88.74%降低至1.11%。

Identifying high-risk pipelines and reducing their failure probability is an important means to alleviate urban waterlogging.Therefore,this paper proposed a high-risk pipeline identification method based on the correlation between drainage capacity and failure probability.Firstly,the critical criterion for pipeline failure was that the fullness was equal to 1,and the failure probability of pipeline under the design rainfall scenario was calculated based on Monte Carlo sampling.Secondly,SWMM was used to evaluate the drainage capacity of the pipeline.Then,the K-means clustering algorithm and the piecewise regression analysis method were used to construct the correlation between the drainage capacity and the failure probability,and the discriminant threshold of the high-risk pipeline was deduced by the correlation.Taking a drainage area in Fengtai District of Beijing City as an example,the failure probability of 3.64%was deduced as the identification threshold of high-risk pipelines under the scenario of three-year rainfall.Combined with the longitudinal profile of high-risk pipelines,the causes of waterlogging were analyzed,and the rehabilitation plan was formulated.The simulation results showed that the proportion of high-risk pipelines in the total number of rainwater pipelines was reduced from 91.39%to 2.32%after rehabilitation.The proportion of the total length of the high-risk pipeline to the total length of the rainwater pipe network decreased from 88.74%to 1.11%.