不同绿化带对城市道路噪声削减的影响

Investigation of Traffic Noise Reduction on Urban Road by Different Green Belts

不同树种和结构的绿化带对交通噪声消减的影响是不同的。在上海市选取13个有代表性的城市道路绿化带进行减噪效果测定,结果发现：1）在具有相同遮蔽率的情况下,圆柏（Sabina chinensis）的降噪效果最好,其次分别是夹竹桃（Nerium indicum）、香樟（Cinnamomum camphora）和广玉兰（Magndia grandiflora）;Ⅲ级遮蔽率下距道路10 m处的圆柏和广玉兰的降噪值差异达2.4 d B（A）。2）降噪能力与绿化带遮蔽率呈正相关关系,遮蔽率越高,降噪效果越好;距道路10 m处的不同级遮蔽率植被的降噪贡献差异在3.2~3.9 d B（A）。3）绿化带减噪效果的距离衰减特征与二次多项式模型较吻合;遮蔽率越高,多项式中系数∣a∣越大,指示单位距离内的噪声衰减量越大,噪声衰减快、传播距离变小,绿化带降噪效果明显。

Green belts with different tree species and structure have different impact on traffic noise reduction. 13 representative urban road green belts in Shanghai were selected to measure the effect of noise reduction by green belts.The results showed that in the same shading rate, Sabina chinensis had the best effect of noise reduction, followed by Nerium indicum, Cinnamomum camphora and Magnolia grandiflora. The difference of noise reduction between Sabina chinensis and Magnolia grandiflora at 10 meters away from the road was 2.4 d B（A） at class III shading rate. The ability of noise reduction was positively correlated with the shading rate of green belts, in which the higher the shading rate,the better the noise reduction effect. The difference of noise reduction among different classes of shading rates at 10 meters away from the road was from 3.2 to 3.9 d B（A）. The distance decay characteristics of the noise reduction effect of the green belts were in good agreement with the quadratic polynomial mode. With the increase of shading rates, the coefficient ∣a∣ in the polynomial model became larger, indicating greater noise attenuation per unit of distance. The faster noise attenuation, the shorter propagation distance and the more obvious noise reduction effect.