成渝高速铁路某高架桥段地面三向振动特性分析

Tri-directional Measurements and Analysis of the High-speed Train induced Ground-borne Vibration on a Viaduct of Chengdu-chongqing High-speed Railway

地面振动是高速铁路运营期的主要环境问题之一,为了研究高速铁路高架桥段地面振动的传播和衰减规律,选择成渝高速铁路某桥梁段进行了现场地面三向振动测试。在时域和频域内分析地面三向振动的时程特征和频谱特征,以及垂向振动、水平向振动随距离的传播特性。结果表明,在同一距离处,横向、纵向振动加速度幅值及有效值均大于垂向;三向振动随距离的增加,加速度幅值及有效值均呈衰减趋势;垂向和纵向振动中,高频成分衰减迅速,低频衰减速度较缓,而横向则是低频和高频均衰减迅速,但远场仍是以低频为主;三向振动远场优势频率均在10Hz左右;计权垂向振级高于水平向振级,未计权的水平向振级均大于垂向振级。

Ground-borne vibration induced by the high speed railway operation is one of the major environmental problems. Previous studies mainly focus on the vertical vibration with the horizontal vibration ignored. In order to study the tri-directional ground-borne vibration of a bridge structure, a field measurement is carried out in a viaduct section of Chengdu-Chongqing high speed railway. First of all, the tri-directional vibration characteristics of time history and frequency spectrum are examined in time domain and frequency domain respectively. Then, the propagation characteristics of the weighted and plain root-mean-squares (RMS) of accelerations in the three directions are investigated. The results demonstrate that the weighted RMS of acceleration of the vertical vibration is greater than that of the horizontal vibration. However, the plain RMSs of accelerations of both the longitudinal and lateral vibrations are greater than that of vertical vibration. Therefore, the horizontal vibration should not be neglected when analyzing the propagation characteristics of the ground-borne vibration induced by high-speed railway. Moreover, the vertical weighted acceleration can play a dominant role when evaluating the environmental effect of high-speed railway vibration.