城市轨道交通高架线路敷设阻尼钢轨噪声特性

为研究城市轨道交通高架线路敷设阻尼钢轨前后列车通过时段噪声变化规律，以敷设了阻尼钢轨的广州某高架线路为研究对象，通过对高架线路敷设阻尼钢轨前后轨道旁、距行车轨道中心线7.5和30 m处测点进行现场噪声试验，分别从时域统计、频谱和插入损失等方面分析了高架线路改造全过程，包括换轨前、换轨后、刚敷设阻尼钢轨及敷设阻尼钢轨运营半年后列车通过时段噪声变化规律。分析结果表明:换轨和敷设阻尼钢轨作为源头上的降噪措施具有一定的降噪效果，噪声源强处2种措施分别降噪1.1、2.9 dB(A)，敷设阻尼钢轨能降低钢轨Pinned-Pinned振动辐射产生的噪声；换轨前高架线路列车通过噪声能量主要集中在100~3 000 Hz，分别在100~125 Hz和2 000 Hz附近出现第1、2个峰值，换轨后、刚敷设阻尼钢轨及敷设阻尼钢轨运营半年后的列车通过噪声能量主要集中在500~2 000 Hz，峰值频率出现在800 Hz附近；高架线路整个施工改造过程中60 Hz以下低频噪声变化较小，60 Hz附近的频率为轮轨系统的固有频率，高架线路改造并未使轮轨系统固有特性发生较大改变；敷设阻尼钢轨运营半年后相比刚敷设阻尼钢轨时，在距轨道中心线7.5和30 m处，1 000 Hz以上高频噪声变化较小，桥梁局部结构振动产生的辐射噪声(100~300 Hz)出现了一定的增大。 

Noise characteristics of urban rail transit viaduct installing damping rail

In order to study the variation of train pass-by noise before and after installing damping rail on urban rail transit elevated line, a Guangzhou viaduct with damping rail was taken as the research object. Based on the field noise test at the measuring points near the track before and after the damping rail laying on the elevated line, 7.5 and 30 m away from the center line of the running track, the variation of train pass-by noise was analyzed from the time domain statistics, frequency spectrum and insertion loss in the whole process of elevated line reconstruction, including before rail replacement, after rail replacement, just installing damping rail and after half a year's operation. Research results show that rail replacement and installing damping rail as noise reduction measures at the noise source can achieve noise reduction effect to a certain extent, the noises reduce 1.1 and 2.9 dB(A), respectively. Installing damping rail can effectively reduce the noise caused by rail pinned-pinned vibration radiation. Before rail replacement, the pass-by noise energy around the elevated line is mainly concentrated in the range of 100-3 000 Hz, with the first and second peaks around 100-125 Hz and 2 000 Hz, respectively. After rail replacement, just installing damping rail and after half a year's operation, the pass-by noise energies are mainly concentrated in the range of 500-2 000 Hz, with the peak frequency around 800 Hz. The low frequency noise under 60 Hz changes little during the whole construction of the elevated line. The frequency near 60 Hz is the natural frequency of wheel-rail system, and in the whole process of installing damping rail, the natural characteristics of wheel rail system change little. Half a year later after installing damping rail, compared with that just installing damping rail, at 7.5 and 30 m away from the track center line, the change of high-frequency noise above 1 000 Hz is smaller, and the radiation noise (100-300 Hz) produced by the local structural vibration of the bridge increases to a certain extent. 1 tab, 11 figs, 30 refs.