公路隧道内主动降噪声场研究

Study on Active Noise Control Sound Field in Highway Tunnel

针对公路长大隧道内噪声声压级超过90dB,且目前多采用降噪路面或隧道壁喷涂吸声材料进行被动降噪的现状,基于声波干涉原理尝试对高速公路隧道进行主动降噪。为了确定公路隧道内主动降噪技术的适用条件、实现方法和降噪效果,采用理论推导和有限元仿真相结合的方法,构建了沥青混凝土路面公路隧道内主动降噪声场模型,在隧道尺寸和噪声源位置确定的情况下,模拟分析噪声源频率、主动声源位置等因素对隧道声场降噪效果的影响,并将模拟结果与现场实际隧道主动降噪试验结果进行对比。结果表明:确定了噪声源位置和降噪区域后,根据所提出的噪声源、主动声源和降噪位置的空间关系式,以及主动声源应位于隧道断面中轴线上、运输车辆限高要求等因素,可以确定使需降噪区域实现最佳降噪效果的主动声源摆放位置;噪声频率越低降噪效果越好,主动降噪技术对100Hz左右的沥青混凝土路面公路隧道噪声降噪效果显著;噪声频率为125Hz时,在隧道断面中轴线上沿纵向每隔3m布置一台主动声源,可在工人检查走行区域的人耳高度处实现横向宽1m、纵向长2m的区域降噪,该区域降噪幅度为3~8dB;研究成果可为高速公路隧道内的主动降噪提供参考。

Aimed at the situations that sound pressure level（SPL）of the noise is more than 90 dB in the long highway tunnels and noise-reducing pavement and the sound absorbing material sprayed on the tunnel wall are used as the traditional passive noise-reducing techniques,the active noise control methodology was tried in attempt to solve the noise control problem based on principals of interfernece of acoustic waves in the highway tunnels.In order to determine the applicable conditions,the realization method and the effect of active noise-reducing technology in the highway tunnel,the active noise-reducing model in highway tunnel with asphalt concrete pavement was constructed,through method of combining theoretical derivation with finite element imitation.The effects of noise source frequency,active noise source location and other factors on the noise-reducing effect of the tunnel sound field were simulated and analyzed withdetermined tunnel dimension and noise source location.The simulation results were compared with the experimental results of the active noise-reducing tests in field.The results show that after making sure the location of the noise source and the noise reduction area,the optimal placement location of the active sound source can be determined in the area which needs noise reduction,according to height limit,the regulation that active sound source should be located on the axis of the tunnel section,and the space position relation formula of noise source,active noise source and noise reduction position.The lower the noise frequency is,the better the noise reduction effect is.The active noise-reducing technology has a significant effect on the noisereducing in highway tunnel with asphalt concrete pavement,whose noise frequency is about100 Hz.When noise frequency is 125 Hz,arranging active sound source on the axis of the tunnel section every 3malong the longitudinal direction,the noise-reducing region with the horizontal width of 1mand the longitudinal length of 2mcan be realized at the ear height of the workers in the walking area of inspection.The noise-reducing range is 3to 8dB.The results can be referred for the active noise control in highway tunnel.