公路隧道噪声降噪案例研究

隧道型公共设施的声环境，可以使用大量具有高吸声系数的吸声构造，铺设于隧道拱壁及轨道铺面，以降低混响时间及噪声。文中以在湖南省常张高速公路关口哑隧道吸声安装工程为例，在铺设吸声构造后，其混响时间在装吸声构造后在各1／3倍频带约减少64％～84％，预估降噪量则为4．7～8．5dB之间，在200Hz～800Hz之间，降噪量则有7．1dB～8．5dB之间，降噪效果显著。如以实际公路噪声特性预估，降噪量约有6．3dB（A），SIL（speech interference level）则有6．6dB改善效果。

Highway tunnel noise reduce case studies

The reverberation time and noise level of tunnel-typed public works can be reduced by adding large amount of acoustical structure with high absorptive coefficient. These absorptive structures can be applied on the curved wall and track bed. After applying the CEMCOM acoustical material, the reverberation time was reduced about 64%-84% and the noise reduction level was predicted about 4.7dB-8.5dB in the measured 1/3 octave bands for the Guan-Kou-Ya tunnel of Chang-Zhang highway, Hunan Province. Especially, the predicted noise reduction levels are about 7.1 dB to 8.5 dB between 200 Hz and 800 Hz in the measured 1/3 octave band. Using a noise spectrum from a current express way, the noise reduction level is predicted about 6.3 dB（A） and the speech interference level is reduced about 6.6 dB.