隧道内有砟轨道铺设弹性轨枕的动力特性分析

Dynamic Analysis of Laying Elastic Sleeper on Ballast Track in Tunnel

弹性轨枕已被应用于国内外多条有砟轨道线路,铺设于路基、桥涵地段以减小道砟受力。为探明隧道内有砟轨道铺设弹性轨枕的适用性及其减振性能,基于动力学理论与有限元法,建立车辆-有砟轨道-隧道空间耦合动力学模型,分析弹性轨枕对车辆、轨道以及隧道动力响应的影响,并对枕下垫层合理刚度进行探讨。结果表明:弹性轨枕能保证隧道内行车的安全性和平稳性,车辆动力学指标变化不大;枕下垫层会导致钢轨、轨枕垂向位移显著增加,但可大幅降低有砟道床动态响应;相比普通有砟轨道,弹性轨枕具有很好的减振效果,隧道壁振动最大减小17dB,发生于80Hz中心频率处;从控制轨道振动和位移、保证减振效果的角度考虑,建议枕下垫层刚度取40~60kN/mm。

Elastic sleeper has been applied to the subgrade,culverts and bridges of different ballast track lines in China and in the world to reduce the ballast force.To investigate the applicability and vibration absorption performance of elastic sleeper on ballast track in tunnel,a spatial coupling dynamical model for a vehicle-ballast track-tunnel system was established based on dynamics theory and finite element method.Based on the model,the influence of the elastic sleeper on the dynamic responses of vehicle,track structure and tunnel was analyzed.In addition,the proper rigidity value of the sleeper pad was investigated.The results show that laying elastic sleeper in tunnel can well ensure the running safety and stability of trains,resulting in little change of dynamic indexes of the vehicle.The sleeper pad can significantly increase the vertical displacement of rail and sleeper while it can significantly reduce the dynamic response of the ballast bed.Elastic sleeper has excellent vibration absorption ability,specifically up to 17 dB tunnel wall vibration reduction which occurs at the center frequency of 80 Hz,compared with ordinary ballast track.Proper rigidity value of sleeper pad is suggested to be from 40 to 60 kN/mm from the prospective of the control of track vibration and displacement and ensuring vibration absorption effect.