基于地震行车危险性分析的桥梁网络易损性研究

Bridge Network Vulnerability Assessment Based on the Hazard of Moving Vehicle Over Bridge

基于中小地震作用下,高速铁路列车脱轨可能造成线路阻塞,本文提出一个考虑区域性地震作用下的高速铁路网络连通易损性的分析框架.以我国西南地震多发区一个密集的桥梁网络覆盖地域为例,通过PSHA方法确定桥梁场址的地震危险性参数,得到了任意地震作用水准下的场址加速度反应谱,将地震时桥上发生桥上行车的危险性概率作为网络节点关闭概率,再通过基于改进后的Order-X网络连通度分析,进而得到了不同水准地震作用下的网络连通概率.分析结果表明:地震小区划和宏观区划烈度间对桥梁危险性的估计差异,是形成地震网络易损性分析复杂性的重要影响因素,考虑行车安全性是构成地震场作用下的桥梁网络易损性分析重要组成部分.

The mid-small earthquakes could induce the vehicle derailment on bridges as well as the blockage of high-speed railway lines.To analyze this hazard scenario and risk,a framework is proposed to investigate the connectivity vulnerability of China high speed-railway network under the effect of regional earthquake.Based on a dense bridges network covering an earthquake- prone area of southwest China,the PSHA is performed to get the seismic hazard parameters of every bridge site.As a result,the acceleration response spectrum corresponding to different earthquake recurrence interval is obtained.After vehicle-bridge-earthquake dynamic analyzing, the seismic induced derailment probability of vehicles moving on the bridge is obtained and taken as the closing probability of the nodes in the network.Based on the node closing probability corresponding to different level of earthquake,the Order-X network connectivity algorithm is presented to calculate the network connectivity.The results show that the difference between the micro-zoning intensity and macro-level intensity,which produces the difference in hazard assessment results for bridges,is the key factor that cause the difficulties of connectivity vulnerability analysis,hence,the safety assessment of moving vehicles on bridges is indispensable for the seismic vulnerability analysis of the bridges network.