A STUDY ON THE NOISE BARRIER WITH SOFT ROUND EDGE

软圆边声屏障的研究

• 批准号: 06650659
• 负责人: FUJIWARA Kyoji
• 金额: $ 0.32万
• 依托单位: KYUSHU INSTITUTE OF DESIGN
• 依托单位国家: 日本
• 项目类别: Grant-in-Aid for General Scientific Research (C)
• 财政年份: 1994
• 资助国家: 日本
• 起止时间: 1994 至 1995
• 项目状态: 已结题
• 来源: https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06650659/
• 关键词: ROAD TRAFFIC NOISE; NOISE BARRIER; ACOUSTICAL REACTIVE SURFACE; 音響管; ソフト境界

Recently highway traffic noise level increases gradually day by day and it affects largely on our environment. For reducing this influence a noise barrier is currently being used, the height of barrier increases to get large noise insulation. At present noise barrier of more than 8m is constructed for more than 30km along the highway. A new noise barrier system, by which we can get more attenuation keeping the height lower, is needed. In this study, a new barrier system installing "soft" round obstacle at the barrier edge is examined and the realization of "soft" round obstacle and its problems in practical use are checked.In 1994, the scale model of 1/10 was used to realize the soft round obstacle. The meaning of "soft" is that the sound pressure at surface of the obstacle is zero, and then an arrangement of 1/4 wave length acoustic tubes was employed. Both of measured and calculated sound pressure at the mouth of acoustic tube were very low and the arrangement of acoustic tubes realized "soft" surface at certain design frequency. The effect of installation of "soft" obstacle at the edge was sbout 7dB (A) for the real traffic noise at the point 25m apart from the barrier.In 1995, on the base of the result in 1994 the real scale soft round obstacle was made and its effect was checked experimentally. An hole in each well was opened for water drain and thin fins were vertically set at the well mouth for keeping well clean from litter. Despite of these processing the sound pressure at the mouth was nearly zero and the soft surface was realized. This soft round obstacle was installed at the existing noise barrier of 3m high for 200m and the effect of the installation was measured. It was about 3dB (A) at points near to the barrier, but when the distance from the barrier increases it reduces. The additional study on the obstacle would be needed for practical use.

近年来，公路交通噪声水平日益增高，对环境的影响越来越大。为了减少这种影响，目前正在使用声屏障，屏障的高度增加以获得大的隔音效果。目前，公路沿线沿着30余公里，已建成8米以上的声屏障。需要一种新的声屏障系统，通过这种系统，我们可以在保持较低高度的情况下获得更大的衰减。本文研究了一种在护栏边缘设置“软”圆形障碍物的新型护栏系统，并对“软”圆形障碍物的实现及其在实际应用中存在的问题进行了检验。“软”的意思是障碍物表面的声压为零，然后采用1/4波长的声管布置。在一定的设计频率下，声管管口处的实测声压和计算声压都很低，声管的布置实现了“软”表面。在边缘设置“软”障碍物，对距障碍物25 m处的真实的交通噪声的影响约为7 dB（A），1995年在1994年试验结果的基础上，制作了真实的比例软圆障碍物，并对其效果进行了试验验证。每口井均开孔排水，井口垂直设置细翅片，保持井内清洁，防止垃圾。尽管进行了这些处理，但嘴部的声压几乎为零，实现了柔软的表面。在现有3米高的声屏障上安装了200 m的软质圆形障碍物，并测量了安装效果。在靠近障碍物的点处，它约为3dB（A），但当与障碍物的距离增加时，它会减小。需要对这一障碍进行进一步研究，以供实际使用。