基于现场锤击试验的地铁轨道振动特性分析及参数研究

近来,由于轮轨共振而产生的地铁钢轨异常波磨问题备受关注。轨道结构动力特性分析是开展轮轨耦合振动研究的基础,地铁轨道结构的动力特性取决于各组成部分(钢轨、扣件、轨枕和道床等)的物理特性及其组合形式。基于轨道结构的周期性频域解析模型,结合北京地铁在线锤击试验,通过计算轨道结构在脉冲荷载下的频响函数,对0~2000Hz频段内轨道结构的动力响应主频进行分析;并通过改变轨道结构参数,分别研究了不同轨道结构参数对各轨道结构动力响应主频的影响情况。研究结果表明:轨下支撑刚度对钢轨共振频率影响较大,枕下支撑刚度对轨道系统共振频率影响较大,轨下和枕下支撑阻尼仅能改变各共振频率点的响应幅值;轨枕支撑间距对pinned-pinned共振频率影响较大,对其他共振频率点的影响较小。

Characteristic Analysis and Parameter Study of Metro Track Structure Vibration Based on in-Situ Hammer Excitation Test

The abnormal rail corrugation,which is caused by wheel-rail sympathetic vibration,hasrecently become a serious problem in metro lines. It should be noted that the study on the dynamic characteristics of metro track structure is the analysis foundation of wheel-rail coupling vibration,while the dynamic characteristic of metro track structure highly depends on the physical characteristics of the components( rail,fastening,sleeper and track bed,etc.) and on their combination forms. In this paper,based on the periodic frequency-domain analytical model of track structure and in-situ hammer excitation test at Beijing Metro,the frequency response function of the track structure under the action of impulsive load was calculated,so as to analyze the dominant frequency of dynamic response of the track structure ranging from 0 to 2000 Hz frequency bands. Furthermore,by changing the parameters of the track structure, the different parameters of track structure which have influence on the dominant frequencies of dynamic response of track structure were researched respectively. The research results indicate that: the stiffness of rail support has a greater influence on the resonant frequency of the rail; the resonant frequency of the whole track system highly depends on the stiffness of sleeper support; the damping of the rail support and sleeper support can only change the response amplitude of every resonant frequency point. Besides,the support spacing of sleeper has a greater influence on the pinned-pinned resonant frequency,but a less influence on other resonant frequency points.