LOS声屏障降噪效果评价
Noise reduction effect evaluation of LOS sound barriers

为了评价LOS声屏障在噪声水平超标较小与住户较少地区的应用效果,对美国印第安纳州I-465高速公路新型LOS声屏障试验段进行噪声测试与TNM分析,研究了路面类型、车辆速度、交通量、降噪系数、声屏障高度与声屏障延长对LOS声屏障降噪水平的影响,评价了LOS声屏障应用效果,提出了关键设计参数。研究结果表明:LOS声屏障适用于噪音水平超标较小与住户较少的地区; 路面类型对降噪效果影响较大,将水泥混凝土路面更换为密级配沥青混凝土路面与开级配沥青混凝土路面可以明显提高降噪幅度和降噪有效率; 采用限速方法降低噪音并不明显,不推荐采用限速的方法提高声屏障降噪效果; LOS声屏障设计时,设计降噪幅度宜大于6.7 dBA,最低高度应大于路面行驶的大型车辆高度,最大高度不超过6.6 m,最佳高度由设计年限内降噪效果模拟分析确定。
In order to evaluate the application effect of line of sight(LOS)sound barrier in the areas with less excessive noise level and fewer households, the noise monitoring and traffic noise model(TNM)analysis at the highway I-465 with LOS sound barrier in Indiana, USA have been done. The influences of pavement type, vehicle speed, traffic volume, noise reduction coefficient, height and extended length of sound barrier on noise reduction level of LOS sound barrier were analyzed, the application effect of LOS sound barrier was evaluated, and the key design parameters were proposed. Analysis result shows that LOS sound barrier can be applied in the areas with less excessive noise level and fewer households. The influence of pavement type on noise reduction is significant. If cement concrete pavement(CCP)is replaced by dense-graded asphalt concrete pavement(DGACP)or open-graded asphalt concrete pavement(OGACP), the range and effective rate of noise reduction can be improved significantly. It is not effective to reduce traffic noise by lowering speed limits, therefore, it is not recommended. For designing LOS sound barrier, the design noise reduction range should be above 6.7 dBA, the minimum barrier height should be tall enough to block the view of large vehicle and the maximum barrier height is 6.6 m, the optimum height of LOS sound barrier in design year should be determined by traffic noise model analysis. 8 tabs, 14 figs, 20 refs