市域铁路声屏障设置研究

The Study on Sound Barrier for Suburban Railway

市域铁路噪声影响突出,需要采取有效的噪声防治措施,声屏障作为主动控制措施,一直被广泛采用。基于市域铁路的特点和运行速度,结合市域铁路成灌线测试数据的分析,从声源特性、声屏障设置原则及声学设计、结构形式等方面对市域铁路声屏障设置开展研究。指出:(1)市域铁路声源主要为轮轨噪声,噪声频谱呈宽频特性,桥梁、路堤区段在低频段和中高频段声能量均较为集中,桥梁二次结构噪声影响不能忽视,声屏障的设置应与桥梁结构减振降噪协同开展。(2)市域铁路声屏障声学设计时,评价时间内不能简单地将铁路噪声源视为无限长线声源,建议直立式声屏障附加长度取值为50~70m。(3)市域铁路列车脉动风压对声屏障结构选型影响较小,应加快对直立式声屏障顶部变化型、顶端降噪器的研制。

Effective noise proof measures are required to minimize the noise triggered by suburban railway. Sound barrier, as one of the active measures of control, has been widely applied. In accordance with the features and operation speed of suburban railway as well as the analysis of the test data of Chengdu-Dujiangyan line, the paper studies the characteristics of noise source, the principles for barrier arrangement, acoustic design, and structural design, etc. The following conclusions arrive：（1） The main noise source of suburban railway is wheelrail noise, which displays the characteristics of wide band frequency, while acoustic energy largely comes at low and medium-high frequency range as the train passes through bridges and embankment. The noise influence induced by the secondary structure of bridge cannot be overlooked. And the sound barrier shall be arranged in a way that complements the efforts of vibration and noise reductions.（2） For the acoustic design of suburban railway, railway noise source cannot be easily regarded as infinite line sound source, and the additional length of sound barrier is suggested to be 50 m to 70 m.（3） Since the fluctuating wind pressure of suburban railway has little impact on the structure selection of sound barrier, the vertical-type sound barriers with varied roofs and top noise reducers shall be developed as soon as possible.