Urban railway ground vibrations induced by localized defects: using dynamic vibration absorbers as amitigation solution

Abstract

Recent increases in urban railway track infrastructure construction are often delayed by distress to occupants caused by ground-borne vibration arising from the passing of the rail vehicle. Mitigation measures are proposed as a solution if they prove their efficiency in reducing these vibrations. In this paper, we present a practical study of dynamic vibration absorbers (DVAs) as a possible measure. A complete numerical study based on a recently developed two-step approach is performed. A detailed multibody model for the vehicle is coupled to a finite element/lumped mass model for the track in order to predict the forces acting on the soil. Then a 3D finite element model of the soil simulates the ground wave propagation generated from these dynamic forces to evaluate the level of vibration in the surrounding area. Having validated this model in the past, it is used to determine the effectiveness of DVA placed either in the vehicle or on the track. Compared to existing studies presenting DVA calibrations in terms of frequency response functions, realistic simulations are presented, based on the specific case of the T2000 tram circulating in Brussels traversing a localized defect. The results demonstrate that a DVA placed on the vehicle remains an interesting solution, provided that the mass is sufficient (mass ratio of 0.1).

摘 要

目 的

基于动力吸振器理论提出一种控制城市轨道交通地面振动的有效措施。

创新点

• 1. 确定动力吸振器安装在车辆或轨道上的最优位置和动力学参数;

• 2. 采用提出的两步分析法真实模拟布鲁塞尔有轨电车在通过轨道局部缺陷时引起的地面振动;

• 3. 探明动力吸振器安装在车辆或轨道上对控制地面振动的有效性。

方 法

• 1. 通过对列车–轨道耦合动力学系统进行模态分解, 得出在不同位置安装动力吸振器的最优动力学参数;

• 2. 采用索提出的两步法预测不同工况下城市轨道交通的地面振动: 首先建立多体车辆与轨道耦合动力学模型, 计算作用在土体上的动力作用, 然后建立三维土体有限元模型, 模拟动力作用引起的地面波传播及周边的地面振动。

结 论

将动力吸振器安装在车辆上是降低城市轨道交通地面振动的有效措施。