考虑地震强度空间变异性的地铁系统连通可靠性分析

Connectivity Reliability Evaluation of Subway Systems with Spatially Variable Seismic Intensity

考虑地震强度的空间变异性,本文提出一种以震后通行能力为目标的地震作用下地铁系统连通可靠性评价方法。首先,根据历史地震资料和地震烈度衰减关系,开展目标区域地震危险性分析,生成具有空间变异性的地震动峰值加速度场;其次,采用图论建模方法构建地铁网络拓扑模型,并将地震动场输入网络;再次,结合结构地震易损性模型计算地铁车站、区间隧道的地震失效概率,并模拟地铁网络的震后状态;最后,引入有效连通的概念建立了3种指标:网络连通可靠度、车站连通可靠度和运营线路故障率,基于Monte Carlo模拟方法从不同角度对地铁系统的抗震连通可靠性进行分析。基于上述流程以北京市城六区地铁系统为例进行抗震连通可靠性分析。结果表明:地震强度的空间变异性对系统连通可靠度的影响显著;在50年超越概率为10%的地震作用下该地铁系统中88%的车站之间能够实现有效连通;运营线路之间相互交错形成闭环能有效提高系统的连通可靠度。

With the aim of post-earthquake traffic capacity assessment of the subway system,this paper presents a new method for seismic connectivity reliability evaluation considering the spatially variable seismic intensity.First,based on the historical earthquake records and the seismic intensity attenuation model,the seismic hazard analysis of the target site was conducted to generate a peak ground acceleration field with spatial variability.Second,the graph theory modeling method was adopted to construct the subway network topology model,and the seismic motion field was input into the network.The seismic failure probability of subway stations and interval tunnels was estimated based on the seismic fragility models and simulated the post-earthquake state of the subway network.Finally,the concept of effective connectivity was introduced to establish three indicators:network connectivity reliability,station connectivity reliability,and line failure rate.The seismic connectivity reliability of the subway system was analyzed from different perspectives based on the Monte Carlo simulation.The subway system of the six districts of Beijing was used as an example to analyze the seismic connectivity reliability based on the above process.The results showed that the spatially variable seismic intensity has a significant effect on the connectivity reliability of the system.88%of the stations can connect effectively under the seismic with a probability of exceeding 10%in 50 years;The closed loops formed by interlocking subway lines can effectively improve the connectivity reliability of the system.