地震动分量对车-轨-桥系统动力响应影响研究

Influence of Ground Motion Components on Dynamic Response of Train-Track-Bridge System

为研究横向、竖向、纵向及三向地震动分量对车-轨-桥系统动力性能的影响,以高速铁路10跨32m双线简支箱梁桥为背景进行分析。采用仿真分析程序TTBSAS,选取一致激励模式输入10条典型地震波,分析在无震,横向、竖向、纵向及三向地震动分量作用下车-轨-桥系统的钢轨横(竖)向位移、加速度等桥梁结构动力响应,以及脱轨系数、轮重减载率、轮对横向力等列车动力响应。结果表明:在不同地震动分量作用下,高速铁路简支梁桥的横向和竖向动力响应具有弱耦合性;横向地震动分量会同时增大钢轨的横向和竖向动力响应;横向地震动分量对桥上列车行车安全的威胁最大,在进行地震作用下的车-轨-桥系统行车安全性研究时,可考虑仅输入横向地震动分量进行计算。

To study the influence of horizontal,vertical,longitudinal and three-dimensional ground motion components on the dynamic performance of train-track-bridge system(TTBS),a simply-supported high-speed railway bridge that accommodates two tracks and contains 10 equal spans of 32 m is taken as a case.With the uniform excitation mode,10 typical seismic waves were input into the simulation analysis program TTBSAS,to analyze the dynamic responses of the bridge structure under the action of horizontal,vertical and longitudinal and three-directional ground motion components,entailing the lateral(vertical)displacement and acceleration of the steel tracks,and the dynamic responses of the trains as well,including the derailment coefficient,wheel weight reduction rate and wheelset lateral force.The results show that the lateral and vertical dynamic responses of the simply-supported high-speed railway bridge are weakly coupled under the action of different ground motion components.The horizontal ground motion component can intensify the lateral and vertical dynamic responses of the steel tracks at the same time,and is the biggest threat to the running safety of trains.It is suggested that the horizontal ground motion component be taken as the only seismic input in the study of safety of the train-track-bridge system.