有源声屏障对地铁轮轨噪声的消减性能

Noise reduction performance of active noise barrier for metro wheel-rail noise

摘要:

为降低轮轨噪声对地面沿线的危害,在临近地铁线路的位置布设有源声屏障,使噪声的低频段和高频段可分别被有源消声系统和声屏障显著消减,为了科学指导有源声屏障的设计,研究由次级源参数变化所导致的声场变化规律。基于边界元理论,建立考虑了列车、声屏障、轨道的半自由场模型,将计算结果同北京地铁13号线实测信息进行对比验证,进而在模型中增设沿轨道纵向等间距排列的次级源,经仿真分析确定次级源最合理位置、消声频段、消声区界线、消声量；构建关于次级声和噪声干涉相消的数学模型,通过理论推导验证了仿真结论的合理性。研究结果表明:次级源最合理位置与轨道对称轴间隔一个声波长度、和声源等高、具有短于半个声波长度的纵向间隔；次级声对150~320 Hz轮轨噪声消减显著,消声区面积与频率呈正相关；在列车左右两侧对称布设次级源纵列的消声效果优于在列车一侧布设的效果；在声屏障的基础上布置次级源纵列,能令声影区内总声压级普遍降低3~12 dB,且令声影区外的放大值基本不超过3 dB,并且确保列车内声场变化不大。

Abstract:

To reduce the influence of wheel-rail noise on the area along the metro railway on the ground, active noise barriers were arranged near the metro track. The low-frequency noise could be significantly reduced by the active silencing system, and the high-frequency noise could be significantly reduced by the noise barrier. To guide the design of active noise barrier, the influence of secondary source parameters on metro noise field was studied. Based on the boundary element theory, a semi-free field model consisting of train, noise barrier and track was established. The correctness of the model was verified based on the measured data of Beijing Metro Line 13. The secondary sources were then arranged in the model along the longitudinal direction of the track with equidistance. By analyzing the numerical results, the most reasonable position of secondary sources, the silencing frequency, the silencing area boundary, and the silencing quantity were determined. A mathematical model of secondary sound interfering with noise was constructed to verify the rationality of the simulation conclusions. Results show that the most reasonable position of the secondary sources and the track axis were separated by a noise wave length. The height of the most reasonable position of the secondary sources was equal to that of the noise source. The most reasonable position of the secondary sources had a longitudinal interval shorter than half the noise wave length. Secondary sound could significantly reduce the wheel-rail noise of 150-320 Hz, and there was a positive correlation between silencing area and frequency. The silencing effect of bilateral secondary source array arranged on left and right sides of the train was better than that of unilateral sources arranged on one side. Setting secondary source arrays on the basis of noise barriers could generally decrease the total sound pressure level (SPL) in the sound shadow area by 3-12 dB, and the amplification value outside the sound shadow area basically did not exceed 3 dB, and the sound field in the train had little change.