扣件失效对地铁整体道床动力性能的影响

Influence of fastener failure on dynamic performance of metro monolithic track system

为研究扣件失效对地铁整体道床轨道及车体振动性能的影响,基于结构动力学理论建立地铁列车-整体道床(隧道衬砌)耦合分析模型,采用弹簧阻尼模拟土体,采用模态分析和Newmark法求解动力响应,研究列车速度、扣件失效数量和轨道不平顺对地铁车轨振动的影响。研究结果表明:扣件失效会加剧系统振动响应,对车体加速度影响较显著,但对钢轨位移和轮轨接触力的影响相对较小;列车速度对钢轨位移和邻近扣件反力的影响较小,对车体加速度和衬砌加速度影响显著;随着失效扣件数量增加,车体竖向加速度等系统动力响应增幅明显;在考虑轨道不平顺的情况下,扣件失效会加大钢轨加速度和衬砌加速度的振级,而车体竖向加速度可作为确定失效扣件位置的敏感指标;扣件失效会增大邻近扣件的受力,造成二次失效,影响乘客舒适性和周围环境振动,需要及时检修,保障地铁正常运行。

In order to study the influence of fastener failure on the dynamic performance of metro train/monolithic track system,a metro vehicle-monolithic bed(tunnel lining)coupling system model was established based on structural dynamics theory.The spring damping was used to simulate the soil.Modal analysis and Newmark method were adopted to solve the dynamic responses.The effect of train speed,fastener failure number and track irregularity on vibration response of train-track system was studied.The results show that the fastener failure can aggravate the vibration responses of metro train-track system,especially the carriage acceleration,but it has less effect on the rail displacement and the train/track reaction force.Train speed can barely affect the rail displacement and the reaction force of the adjacent fasteners,but has significant influence on the acceleration of the carriage and lining.With the increase of fastener failure number,the dynamic responses of the system increase greatly,especially the vertical acceleration of the carriage.By considering the track irregularity,the fastener failure can increase the vibration level of rail acceleration and lining acceleration.The fastener failure can lead to the new damage caused by the increase in the reaction force of the adjacent fastener,and it has adverse influence on the passenger comfort and the ambient vibration.Therefore,it is necessary to check and repair in time to ensure the normal operation of the metro line.