Improvement And Optimization Design To Top Structure Of Urban Traffic Noise Barrier

With the development of railway construction and city traffic, noise pollution is becoming more and more serious and need to be solved urgently. Noise barrier has been widely used in home and abroad to reduce traffic noise as an effective method. But how to improve its performance and cut down the cost is a problem of importance to improve the quality of living environment.Calculation model of insertion loss of noise barrier is given according to the principle of noise reduction, providing theoretical basis for the analysis of noise reduction effect and optimization design of noise barrier. Combined with the actual measurement of Beijing Subway Line13Xizhimen to Dazhongsi interval, several different structure forms of noise barrier models are established by the acoustic simulation software RAYNOISE to simulate the noise reduction effect. The noise characteristics are analyzed with the insertion loss simulation value. The result indicates that T-shape noise barrier works best overall on noise reduction at the same height and with the same material.Based on former works, the top structure of T-shape noise barrier is improved in accordance with the quadratic residue diffuser. And a variety of new programs with different top structure of noise barrier are designed for the frequency range of traffic noise. The noise reduction effect is improved significantly compared with the insertion loss of noise barrier with rigid surface. It is also found that insertion loss is strongly related to design frequency and the well width of QRD. Reducing the design frequency of QRD shifts the performance improvement towards lower frequency, and therefore the most efficient model for traffic noise is a barrier covered with a QRD tuned to around400Hz.The optimization design scheme is proposed with an analysis of height, length, thickness of noise barrier. Noise reduction and total cost are regarded as objective function, and height and length of noise barrier are variables. Through numerical calculation using Matlab, the best design scheme is carried out.