摘要
为了提高铁路声屏障降噪效果预测的准确程度,在现有高速铁路声屏障声学计算公式的基础上,考虑声波在声屏障与列车车体之间的声波反射现象,推导出考虑一次反射声的高速铁路声屏障插入损失计算公式。结果表明,在单声源模式下,考虑一次声波反射后,声屏障插入损失比不考虑反射声的情况降低了0. 9~2. 6 d B。因此,在高速铁路声屏障设计中宜考虑噪声在声屏障与车体间的反射作用对降噪效果的影响。
The purpose of this paper is to investigate the influence of the acoustic wave reflection between the vehicle itself and the sound barrier on the noise reduction effect for the high-speed railway sound barriers.And,for the need of calculation,we have proposed in the paper the calculation formula of the theoretical derivation and analysis on account of the reflection of the sound waves based on the traditional prediction method of the barrier insertion loss and the theory of the free sound field.In the process of derivation,the sound source feature of the wheelrail rolling noise of EMU can be modeled as the linear sound source according to the model given in the reference specification,while the sound barrier can be simplified to the infinite long sound barrier.But,since the acoustic reflection is related to the vertical directivity of the noise source,the noise incidence angle has been proven to be 21.5°given by the reference specification.And,therefore,2 formulas are to be used to discuss the specific effects of the reflected sound on the insertion loss through the calculation of the same section of the subgrade of a300 km/h high-speed railway,for the influence of the acoustic reflection on the insertion loss has been mainly regarded as the sound absorption coefficients under the different sound barrier heights and the sound absorption coefficient conditions.Hence,literally speaking,the height of the sound barrier should stand for 2.95 m and 3.95 m,whereas the sound absorption coefficient(NRC)has been found in a range from 0.5 to 0.9.Thus,the result of the calculation may indicate that the insertion loss turns to reduce the single equivalent noise source model on account of being taken as the mere acoustic reflection.And,as compared with the current method,the insertion loss can be reduced to by a height barrier of 1.9-2.6 d B and 0.9-1.5 d B for the 2.95 m and 3.95 m,respectively.Therefore,in turn,the comparison results tend to reveal that the reflection of the sound waves may influence the noise reduction of
作者
贺玉龙
陈瑞
张群
HE Yu-long;CHEN Rui;ZHANG Qun(Faculty of Geoscience and Environmental Engineering,Southwest Jiaotong University,Chengdu 610031,China)
出处
《安全与环境学报》
CAS
CSCD
北大核心
2020年第2期698-702,共5页
Journal of Safety and Environment
关键词
环境工程学
声学
高速铁路
声屏障
反射声
虚声源
environmental engineering
acoustics
high-speed railway
noise barrier
reflected sound
imaginary source
