Design And Acoustic Performance Analysis Of Noise Barrier For High-speed Railway

In recent years,our country's high-speed railway transportation got rapid development,with the high speed railway construction mileage increasing and the speed of the train improving.High speed railway brought convenience to the people,at the same time,also produced many problems.The high-speed railway noise pollution seriously affected the quality of life of residents living along the route,it is necessary to control the noise problem.As an effective way to control noise transmission,noise barrier had been widely applied in controlling road traffic and common railway noise.Because of the particularity of the high-speed railway noise,the noise reduction effect of noise barrier is not ideal.Based on the characteristics of high speed railway noise,improving the noise reduction effect of noise barrier is significant to improve the living environment of the resident and promote the development of high-speed railway undertakings.The key to improve noise reduction effect is raising sound attenuation of diffraction.The most effective method is increasing height,setting structure at the top,and controlling the noise in middle and low frequency.With the support of the National Science Foundation project-Broadband acoustic and vibration prediction of ultra-large structure by hybrid energy flow method(51675306)and the National Key technologies Research&Development program-Technology and equipment research of noise and welding dust protection in workshop(2016YFC0801704)and Technology and equipment research of vibration and dust protection in polishing and grinding workshop(2016YFC0801702),the exterior noise of high-speed train had been tested and analyzed.Based on the high-speed railway noise characteristics,the factors which might influence the acoustical performance of noise barrier had been studied.According to the results,a new type of high speed railway noise barrier had been designed and analyzed,compared with the ordinary type,it could reduce the high-speed railway noise more effectively.This paper mainly carried out the following aspects of work:Firstly,the development of high-speed railway undertakings and the noise problem were reviewed,and the harm of noise pollution was expounded.The study and application of noise barrier technology were also introduced since it was the simplest and most effective way to reduce traffic noise.The development of high-speed railway noise barrier was introduced separately,and the existing deficiency of was analyzed.Secondly,the mechanism of noise reduction of the noise barrier were introduced.Methods to decrease the sound diffraction were proposed by increasing height and setting the top shape.Considering the diffusion and absorption effect of the quadratic residue diffuser,it was applied to the top of the noise barrier to control the middle and low frequency noise.To get the information of high-speed railway noise,the exterior noise of high-speed train under different operating conditions was tested,according to relevant test standards and methods.In the testing process,a new type of fairing was designed and utilized,which could improve the accuracy.The equivalent continuous A-weighted sound pressure level,spectral characteristic and the distribution of the sound source were analyzed.Then a calculation model of insertion loss of noise barrier was established using finite element method,based on the high-speed railway noise identification test results.In modeling process,some reasonable assumptions were made and the train body were taken into account.By comparing simulation results with the test results,accuracy of the proposed model was verified.Utilizing the model to study the influence of height,top shape and quadratic residue diffuser to the insertion loss of noise barrier,provided basis to choose parameters in high-speed railway noise barrier design.At last,according to the study results,a new type of high-speed railway noise barrier was designed,and its acoustical performance was analyzed.Compared to the existing erect noise barrier,the new designed one was more effective in noise reduction,especially in control of middle and low frequency noise.