有砟轨道与无砟轨道垂向振动纵向传递特性差异研究

有砟轨道-无砟轨道过渡段存在大量的轨道病害问题,静力学分析与时域内的动力学分析未发现两种轨道间的差异与轨道病害间的关系。根据建立的两种轨道力学模型对比分析两种轨道结构各频段的垂向振动纵向传递特性,得出:轨道垂向振动纵向传播距离与所受荷载激振频段有关。低频段(100 Hz以下),有砟轨道的振动传播距离小于无砟轨道。中频段(100~1 500 Hz),两种轨道的振动传播距离均大幅增加,且有砟轨道的传播距离小于无砟轨道。高频段(高于1 500 Hz),两种轨道纵向传播距离随激振频率增加迅速减小,且有砟轨道的振动传播距离大于无砟轨道。为更好地实现有砟轨道与无砟轨道间动力特性过渡,建议在过渡段设计中减小轨道各部件间的差异,线路养护维修中根据线路设计速度区别控制过渡段两侧轨道几何不平顺。

Study on the Difference of Longitudinal Transmission Characteristics of Vertical Vibration between Ballasted and Ballastless Tracks

There exists a large number of defects on track transition sections between ballasted track and ballastless track. Static analysis and time domain analysis of dynamic analysis failed to find any relationship between them. The longitudinal transmission characteristics of the vertical vibration between two track structures in the frequency domain are compared and analyzed based on the established two track mechanics models. The conclusions are as follows. The vertical vibration and the distance of longitudinal transmission of the track are relevant to load excited frequency band. In low frequency range(below 100 Hz), the distance of vibration transmission of the ballasted track is less than that of the ballastless track. In medium frequency range(100～1 500 Hz), the vibration propagation distances of both tracks are greatly increased and the propagation distance of the ballasted track is less than that of the ballastless track. In high frequency range(more than 1 500 Hz), the vibration propagation distances of both tracks decrease quickly with the increase of the excitation frequency, and the vibration propagation distance of the ballasted track is bigger than that the ballastless track. In order to better realize the transition of dynamic characteristics from ballasted track to ballastless track, it is suggested to reduce the differences among track components in the design of transition section. The geometric irregularity of the tracks on both sides of the transition section should be controlled correspondingly according to the design speeds of the line for track maintenance and repair.