Research On Semi-enclosed Noise Barrier

Since the reform and opening up,China has made great achievements in all aspects.With the rapid economic development,the rapid increase in the size of the city,urban environmental noise problems have gradually become a matter of importance.Urban environment noise affects people’s normal life,work and physical and mental health.In the outdoors,traffic noise seriously affects residential and courtyard by the road;indoors,sound environment of large open-plan offices is not optimistic.Whether in the indoor or outdoor circumstances,setting sound barrier can be used as a common and effective means of noise reduction.Based on this,the concept of semi-enclosed sound barrier is proposed.Semi-enclosed sound barrier refers to the combination of a single traditional sound barrier and the two sound barriers of a certain length,vertical to the former one.On the basis of the concept of semi-enclosed acoustic barrier,the application model of the semi-enclosed acoustic barrier is summarized and established in the typical scene of the outdoor space of the northeast area,namely rural courtyards along roads.A 1:5 scale model experiment about the noise reduction effect of semi-enclosed sound barrier in this model is carried out in the semi-anechoic room,and the same scene to set the same location of the receiver to simulate the analysis of the experimental and simulation results were compared and found that the two groups of results of the trend is basically the same,so the effectiveness of computer software simulation has been determined.Based on the outdoor semi-enclosed sound barrier model,the noise reduction and other influencing factors of the courtyard environment were simulated by using the outdoor environment noise simulation software Cadna/A.First,the height and side length of the semi-enclosed sound barrier were changed.To achieve a certain noise reduction effect of semi-enclosed sound barrier by size settings.And then change the distance between the edge of the courtyard and the centerline of the road and the semi-enclosed sound barrier sound absorption performance to explore the impact of these objective factors on the courtyard sound environment.At the end of this paper,the application model of the semi-enclosed acoustic barrier in the typical indoor flat space is discussed,and the model of the compartmentin the open space is discussed.The application model of the single semi-enclosed compartment in the flat space is established,such as a single partition,to explore the semi-enclosed compartment relative to the advantages of a single partition.Then,three application models of two adjacent semi-enclosed compartments were established.The influence of different factors on the sound propagation between two adjacent semi-enclosed compartments in flat space was simulated.It was found that the height and ceiling sound absorption coefficient are the most influential factors.The height of the compartment and the length of the side of the compartment increase to a certain extent and then continue to increase,the sound pressure level drop smaller,or even no longer decline,or increase because of the increase in sound reflection.