高速移动荷载作用对桥上轨道竖向动力特性的影响

摘要

The paper uses the structure of both the simply-supported box-girder bridge and the track on Chengdu-Guanxian railway line as a starting point,and builds the mechanics model of bridge and track under the influence of moving load. On this ground,the displacement response of the vertical vibration is deducted and relevant data is input into computer program,with the purpose of analyzing the influence of moving load to the vertical-vibration displacement of the track on bridge. The paper calculates the vertical displacement values of each loading at different speed. And the conclusion arrives,as vertical vibration of the track can not be avoided under high-speed moving load regardless of the influence induced by the irregularity of the track itself. It also needs to be pointed out that the speed of the train affects the vibration frequency. At the same time,the vertical vibration amplitude under high-speed load largely surpasses that under static loading. And in the case of Chengdu-Guanxian line,the peak value emerges as the speed reaches 350 km/h. The results can be used as reference for an in-depth understanding of the dynamic performance of the track under the influence of the high speed train.%以成灌铁路简支箱梁桥及轨道结构为背景，建立了移动荷载作用下桥梁轨道力学模型，推导了其竖向振动位移响应并编制计算程序，分析了荷载移动特性对桥上轨道竖向振动位移特性的影响。计算单个荷载以不同速度通过轨道时的竖向位移变化，得出即使没有轨道不平顺影响，高速移动荷载作用仍然会引起桥上轨道竖向振动，且振动频率与速度有关；与静荷载作用相比，轨道的竖向振动振幅大大增加，就成灌铁路而言，竖向位移最大值出现在速度350 km/h 时。研究结果对深入了解高速列车通过桥上轨道时的动力特性有重要指导意义。