Study On Traffic Noise Attenuation By Green Belts Of Plain Road In Beijing And Allocation Model Of Green Belts

The rapid development of road transport brings convenience to peotle's lives and exchange, while producing some negative impact on the surrounding environment, particularly the noise pollution along the highway is gaining attention. Green belt along road can reduce traffic noise, different types of green belt has different characteristics in reducing traffic noise. In this paper, outdoor test and laboratory analysis, field measurement and real-time simulation methods were combined, in order to study the real-time traffic noise attenuation by five different types of green belt by roadside of G101, the simulation test to study the simulative traffic noise attenuation by five different types of green belt were carride out in Green Resort and Bajia Country Park which are far away from traffic noise. The results show that:(1) The visibility and width of green belts are the important factors which effect noise attenuation. The noise attenuation diminish as visibility increases, and increase when the belt wider. The regression equation of noise attenuation and width of belt is y=0.363x+0.354, the coefficient of determination is 0.990.(2) The effect of noise attenuation by mixed belt is better than that of pure belt. In the pure belts, the noise attenuation by Canadensis Moench. or Salix matsudana Koidz. is weaker than that of Robinia pseudoacacia L. or Robinia pseudoacacia. In the mixed belt, the noise attenuation by mixed coniferous or mixed coniferous-broadleaf is better than that of mixed broadleaf.(3) The effects of noise attenuation by green belts in winter is weaker than that in summer, and the value of noise attenuation in winter account 75～96% of that in summer. The reduction values of noise attenuation in winter than summer performances for two levels. One is the mixed belt by coniferous or coniferous-broadleaf which values low 10% or less, the other is mixed by trees-shrubs or pure belt of broadleaf which values low between 20%～25%.(4) The effects of noise attenuation by green blet are different for different noise frequencies, the attenuation is better for 500-2000Hz frequency than other frequencies.(5) This paper designed the anti-noise belt for the sound environment fuction zones which are common on the roadside.