城市轨道交通桥梁-声屏障系统结构噪声特性与预测

针对列车通过城市轨道交通高架时引起的桥梁-声屏障系统结构噪声问题，在某市域铁路箱梁段分别选取无声屏障和直立式声屏障地段，开展噪声现场测试；通过对比无声屏障和直立式声屏障地段的测试结果，分析了箱梁-声屏障系统结构噪声的频谱特性；基于有限元-边界元法，建立了箱梁-声屏障系统振动声辐射数值计算模型，研究了箱梁-声屏障系统结构噪声的空间分布规律，探讨了车速和声屏障高度对箱梁-声屏障系统结构噪声的影响。研究结果表明：当列车以约93 km·h^-1的速度通过时，直立式声屏障对高频轮轨噪声起到了很好的降噪作用，但会使低频结构噪声增大；声屏障结构噪声的影响主要集中于160 Hz以下的低频段，箱梁-声屏障系统结构噪声的峰值出现在63 Hz左右；箱梁-声屏障系统结构噪声呈现出近场随距离衰减较快，远场随距离衰减越来越慢的趋势，箱梁正上方和正下方的结构噪声均超过96 dB，距离桥梁中心线120 m处的结构噪声衰减至72 dB；声屏障结构噪声对于梁侧声场的影响较大，与无声屏障地段相比，设置了高度为3.15 m的直立式声屏障之后，梁侧结构噪声增大了2~5 dB；当车速由93 km·h^-1增大到120 km·h^-1时，箱梁-声屏障系统结构噪声辐射在梁侧最大增加7 dB以上；当声屏障高度由3.15 m增大至6.3 m时，箱梁-声屏障系统结构噪声辐射在梁侧最大增加3 dB以上。

Characteristics and prediction of structure-borne noise from urban rail transit bridge-sound barrier system

The field noise tests were performed beside bridges with and without vertical sound barriers in urban rail transit to investigate the structure-borne noise from the bridge-sound barrier system induced by passing trains. The spectral characteristics of structure-borne noise from the box girder-sound barrier system were analyzed by comparing the test results for bridges with and without vertical sound barriers. A vibro-acoustic radiation numerical calculation model of the box girder bridge-sound barrier system was established by using the finite element-boundary element method. The spatial distribution laws of the structure-borne noise from the box girder-sound barrier system were investigated. The effects of train speed and sound barrier height on the structure-borne noise from the box girder-sound barrier system were assessed. Research results show that when a train passes at approximately 93 km·h-1, vertical sound barriers effectively reduce the high-frequency wheel-rail noise but increase the low-frequency structure-borne noise. The effect of structure-borne noise from the sound barriers is mainly concentrated within the low-frequency band below 160 Hz, and the structure-borne noise from the box girder-sound barrier system peaks at approximately 63 Hz. The structure-borne noise from the box girder-sound barrier system decreases with the increasing distance faster in the near field and slower in the far field. The structure-borne noises both above and below the box girder bridge exceed 96 dB, and the structure-borne noise 120 m away from the centerline of the bridge decreases to 72 dB. The sound barrier structure-borne noise significantly influences the girder-side sound field. Compared to the case without sound barriers, the erection of 3.15 m high vertical sound barriers increases the girder-side structure-borne noise by 2-5 dB. The structure-borne noise from box girder-sound barrier system on the girder side increases by more than 7 dB when the speed of the train increases from 93 to 120 km·h-1. The structure-borne noise from the box girder-sound barrier system on the girder side increases by more than 3 dB when the sound barrier height increases from 3.15 to 6.30 m. 1 tab, 12 figs, 30 refs.