考虑结构因素影响的城市排水系统韧性评估方法

A resilience assessment methodology for urban drainage systems considering the influence of structural factors

摘要

【目的】全球洪涝灾害频发导致城市排水系统面临着越来越多的挑战，不仅包括极端降雨(外部荷载),还有管道老化和破裂等潜在的结构失效(内部荷载)所带来的不确定威胁。为研究外部极端降雨和内部结构失效下城市排水系统韧性水平，【方法】考虑管龄和流速的影响，提出结构失效概率计算方法，构建不考虑结构因素的超标荷载情景和考虑结构因素的复合情景。在综合考虑城市排水系统对极端荷载的响应过程预备阶段、响应阶段和恢复阶段的基础上，选取评估指标，建立基于云模型的韧性评估模型，并将提出的方法应用于研究区进行案例分析。【结果】结果显示：城市排水系统在复合情景下的节点积水总量与超标荷载情景相比增加了60%以上，节点平均积水时长增加了1.0 h以上；拓扑结构优化之后，城市排水系统在超标荷载情景和复合情景下的节点积水总量分别下降了24.7%~30.1%和20.5%~48.4%。【结论】结构失效对城市排水系统的韧性有一定影响，导致排水能力下降；拓扑结构优化在一定程度上可以提升系统韧性。所提方法能够有效评估极端荷载下城市排水系统的韧性，并为极端荷载下城市排水系统的安全运行提供参考。

Abstract

[Objective] Frequent global flooding has led to increasing challenges for urban drainage systems, including not only extreme rainfall, but also the uncertain threats posed by potential structural failures such as pipe deterioration and bursting. In order to study the level of resilience of urban drainage systems under extreme external rainfall and internal structural failure, [Methods] considering the influence of pipe age and flow velocity, the structural failure probability calculation method is proposed, and the overloading scenario without considering structural factors and the composite scenario with considering structural factors are constructed. Based on the comprehensive consideration of the preparatory stage, response stage and recovery stage of the response process of urban drainage system to extreme loads, the resilience assessment indexes are selected and a resilience assessment model based on cloud model is established. The proposed method is applied to the study area for case study analysis. [Results] The result show that the total flood volume in the urban drainage system under the composite scenario increased by more than 60% compared with the exceeding load scenario, and the average flood duration increased by more than 1.0 h. After topology optimization, the total flood volume in the urban drainage system under the exceeding load scenario and the composite scenario decreased by 24.7%~30.1% and 20.5%~48.4%, respectively. [Conclusion] Structural failure has a certain impact on the resilience of urban drainage systems, leading to a decrease in drainage capacity; topology optimization can improve the system resilience to a certain extent. The result show that the proposed method can effectively assess the resilience of urban drainage systems under extreme loads and provide a reference for the safe operation of urban drainage systems under extreme loads.

关键词

城市排水系统 / 结构因素 / 极端荷载 / 韧性评估 / 气候变化 / 洪水 / 降雨 / 极端天气

Key words

urban drainage systems / structural factors / extreme loads / resilience assessment / climate change / flood / rainfall / extreme weather

基金资助

水利部数字孪生流域重点实验室开放研究基金项目(Z0202042022)

国家重点研发计划揭榜挂帅项目“特大城市外洪内涝灾害链联防联控应急技术与示范”(2022YFC3090600)