地震作用下高墩刚构桥行车安全性分析

Train running safety analysis of high-pier rigid frame bridge under earthquake action

为分析地震作用下高速列车通过高墩刚构桥的行车安全性,基于列车-轨道-桥梁动力相互作用理论,用三层弹性点支撑梁模型模拟有砟轨道结构、大质量法处理地震力边界条件,建立了地震作用下的列车-轨道-桥梁耦合振动模型。以一座跨度为（88＋168＋88）m的高墩刚构桥为工程实例,计算了El Centro地震动作用下车桥系统的动力响应。分析结果表明：地震作用下高墩刚构桥的面内和面外动力响应存在弱耦合性,列车的行车安全性随地震动幅值、车速的提高而降低;对于该高墩刚构桥,横向地震动对桥上列车的行车安全威胁最大;多遇地震作用下,ICE3高速列车在7~9度地震区的行车安全阈值分别为275、250和225 km/h。

In order to analyze the running safety in case of a high-speed train running over a high-pier rigid frame bridge subjected to earthquake action,a coupling vibration model of seismic-train-track-bridge was set up on the basis of the train-track-bridge dynamic interaction theory. In this model,the seismic action was solved by the large mass method and the ballast track was simulated by the elastic point support model with three layers. As an example,a high-pier rigid frame bridge with spans of（ 88 ＋ 168 ＋ 88） m was modeled,and the dynamic responses of vehicle and bridge system under El Centro seismic ground motion were calculated. The analysis results show that the dynamic responses of the high-pier rigid frame bridge present weak coupling in plane and out plane,moreover the running safety of the train is decreased along with the increase of seismic amplitude and train speed. In addition,the greatest threat to the running safety of the train on bridge is in transverse direction,and the running safety thresholds of ICE3 subjected to frequent earthquake with intensity VII,VIII and IX are 275,250 and 225 km / h respectively.