高速公路绿化林带降噪效果调查与分析

对南京机场高速公路12处林带降噪效果进行长期监测的基础上,分析了高速公路林带树种、宽度、结构、枝下高、郁闭度与宽度乘积以及季节因素对降噪效果的影响。结果表明：针叶乔木在监测期间的平均降噪值最高,达到4.5dB,乔灌草结合的林带结构最佳,其降噪量可达6.7dB;枝下高为4m左右的乔木与枝下高约1m的灌木相互搭配,降噪效果较为显著;绿化衰减量随宽度、郁闭度与宽度乘积等值的增大而增加,宽度每增加10m,平均降噪量增加1dB,而郁闭度与宽度乘积的值每增加10个单位,衰减量可增加1.9dB;夏季林带降噪效果最好,平均降噪量为3.3dB,冬季最差,平均降噪量仅为0.9dB。

Analysis of Influencing Factors on Highway Traffic Noise Attenuation Provided by Tree Belts

Based on the tests of Nanjing airport expressway,the noise attenuation of 12 tree belts is investigated,and some factors that effect highway noise attenuation is analysed,including species,width,structure,average bifurcate height, product of canopy density and width of tree belts, as well as the seasonal factor.The results show that the noise attenuation of coniferous trees is better than the other species,reach to 4.5 dB,the structure of arbor-bush-grass is optimal and the noise attenuation is 6.7 dB;the reduction will be increased when combination arbor with 4 meters in height under brance and shrub with 1 meter in height under branch;green attenuation increases with the width,the product of canopy density and the width and each additional 10 meters width, the average noise volume of 1 dB, when the product of canopy density and the width increase 10 units,the noise can reduce 1.9 dB;in summer noise attenuation is better, the average value is 3.3 dB, while winter is only 0.9 dB.