Traffic Noise Prediction Of Urban Expressway Based On Road Service Level And Its Practical Application

With the acceleration of urbanization,more and more urban roads have been built,which inevitably leads to environmental noise pollution.The prediction of road traffic noise can not only provide reference for urban planning and construction departments from the perspective of noise pollution,but facilitate environmental protection personnel to prevent and control road traffic noise.Nowadays,road parameters used in urban traffic noise prediction(mainly referring to traffic volume and average speed)are mostly collected in a single day.The prediction results based on such parameters cannot guarantee their accuracy and stability.It is necessary to know that even the road parameters at the same time are changing every day and every hour.Therefore,based on the road service level,this paper predicts the influence of traffic noise on urban expressway.The research contents mainly include the following aspects:(1)Briefly introduces various road traffic noise prediction methods and models,introduces the function and calculation principle of the noise simulation and prediction software Cadna/A used in this paper,and introduces the Evaluation Index of road traffic;Introduces the selection of road parameters under each road service level,and divides the parameters range of traffic volume and average vehicle speed in detail.(2)Based on the results of service level partition,using Cadna/a software to simulate and predict the noise influence of expressway under different design speed and different service level.The results show that the noise impact of road is different at different service levels: the road noise changes greatly at the first service level,but the difference is not obvious at the second and third service level.(3)Based on the prediction results of noise impact of expressways at different service levels,the construction distance of buildings near expressways is predicted,finally,the noise reaching distance between the buildings of different heights and the center line of the outermost road is evaluated,and the reaching distance of residential buildings after noise reduction measures is predicted.The results show that without any noise reduction measures,the distance to reach the noise standard of urban residential buildings is often more than 100 meters,and the distance to reach the noise standard of first-class service level is very different from one to four,at the second and third service levels,the standard distance of the building varies little in each section,and the standard distance of the building is greatly shortened with the adoption of noise reduction measures.(4)The noise of a high-speed road section in Chengdu was measured,the environmental parameters around the measuring points were collected outside the measured points,and the measured road section was modeled and the noise impact prediction was carried out by using the satellite map and Cadna/A software,finally,the noise impact of the road section during 17.00 ～ 18.00 working day of a week was evaluated based on the road service level prediction.The results show that when the road service level is used to predict the road noise,it is only necessary to evaluate the overall road service level,and when the actual road noise impact is predicted based on the road service level,the relationship between vehicle speed and vehicle flow should be checked to see if it meets the quantitative relationship between vehicle flow and vehicle speed of this paper.If there is a conflict between practice and theory,the actual data should prevail in the prediction.