板式无砟轨道交通引起的环境振动数值分析

Numerical Analysis on Environmental Vibrations Caused by Slab Ballastless Track Transit

利用已研究出的高速铁路动荷载,采用粘弹性边界,运用有限元法建立轨道-路基-大地二维动力分析模型,分析板式无砟轨道交通引起的振动在大地中的传播特性。计算分析表明:地表的振动强度随着离轨道中心线的距离增加而逐渐衰减。离轨道中心线近处,地表振动较强,而且加速度主要频段在20 Hz以上;离轨道中心线较远处,振动较小,加速度主要频段在10 Hz以下。随着离轨道中心距离的增加,加速度幅值随之减小,而且地表20 Hz以上的振动衰减得较快,10 Hz以下的振动衰减得较慢。

Making use of the developed dynamic load on high-speed railway and viscous-elastic boundary, a two-dimensional dynamic analysis model for track-subgrade-ground is established by finite element method so that the transmission characteristics of vibrations caused by slab ballastless track transit in the ground could be analyzed. The calculation and analysis show that with the distance from the middle line of the track increasing, the vibration intensity of the ground surface decreases, the Vibration of the ground surface closer to the middle line of the track is more intense with the frequency of acceleration more than 20 Hz; while the vibration of the ground surface farther away from the middle line of the track is more weak with the frequency of acceleration below 10 Hz. With the distance from the middle line of the track increasing, the amplitude of acceleration decreases, wherein the ground surface vibration above 20 Hz decreases quickly and that below 10 Hz decreases slowly.