Research And Calculation On Insert Loss Of Railway Barrier

Since the reform and opening-up of our country, the railway construction and the railway traffic have been developed rapidly. However, as the speed of the railway has been increased, the problem of the railway noise also arouses widespread concern. The problem how to reduce the railway noise has caused the attention of many specialists all over the world. Building all kinds of sound barriers are the effective measures of controlling the railway noise and improving the sound environment along the railway. Until now, this method is the most effective way on dealing with the problem. This paper bases on analyzing the principle of noise barrier to reduce the railway noise, and focuses on the mathematics model of sound barrier insert loss. The main work are as follows:Firstly:this paper has made a research on the assessing measure and the assessing standard of the norm on the design of noise barriers. The key point is to compare and analyze some mathematic methods of sound barrier insert loss, including line sound source of infinite length, diffracted attenuation of Frequency band noise, Qian Chuan Diagram Method, Abac. This paper used these methods to forecast the sound barrier insert loss of Qin Shen railway line for passengers traffic, and then compared the forecast and the practical results. The conclusion shows that the fact effect of the barrier noise to reduce the noise has great windages with the result of the traditional theory. This paper analyzed the reason of the windage, and then revised according to the fact situation of our country's railway. As a result,it can be used to forecast our country's sound barrier insert loss.Secondly:this paper bases on the situation of train running and diffracted attenuation of Frequency band noise, (1)give the equal time model and the calculative formula of diffraction loss of infinite line sound source and Finite sound barrier ,(2)analyze the characteristic of Finite sound barrier(the Railway noise source), through constructing calculative model of diffracted sound attenuation of limited length barrier. The paper construct theoretically calculative model of diffracted sound attenuation of railway barrier by using diffracted sound attenuation variable of railway barrier (SEL,LP). According to the amended model, prediction results are more precise and better fit actual facts.Thirdly:the paper based on the detailed research on equal effective frequency, used diffracted sound attenuation variable of railway barrier, according to the difference of speed, type with many data of Jing-jiu Line and Zhe-gan Line, utilized the mathematic program with Matlab to research and analyze the frequency which suits the sound barrier in our country.Lastly:actual project--- Noise Assessment and Control for Shang Hai Xiang Yi Hua Cheng Along Railway.