Prediction And Control Of Acoustic Characteristics Of Platform And Waiting Hall With High-speed Train Passing Through

With the development of railway transportation,the noise problem of the platform and the waiting hall of railway station has attracted more and more attention.The phenomenon of high-speed train passing through the railway station without stopping becomes more and more common.The study on acoustic characteristics of the platform and the waiting hall of railway station is very important.This thesis takes the Fuxing train(Chinese Standard EMU)as an example to study the noise of the platform and the waiting area when passing quickly.To study the sound field characteristics of the platform and waiting hall of the integrated transportation hub,the types of trains passing through were determined,and accordingly,the train was meshed as a reflective surface.Building predictive models for the sound propagation of the platform and the waiting area by the ray tracing method.Then the wheel/rail noise and auxiliary equipment noise generated by the train are defined as the main sound source.The sound field prediction basis of the comprehensive transportation hub later is provided by this model.The main research contents are as follows:When the train passes at 120 km/h,the SPL(sound pressure level)of the platform augment with the decrease of the distance to the track which the train passes.On the platform closest to the non-stop track,the maximum SPL is 96.2 d BA,and the minimum SPL is 82.7 d BA.For any position of platform the SPL exceeds the reference noise limit.The SPL in the waiting room area becomes higher when the field point becomes closer to the hollow area,the maximum SPL is 83.8 d BA;at the same time,the SPL goes lower when the recieving point is getting further to the area connecting the B3 layer,the minimum SPL is 75.8 d BA.The effect of wheel-rail roughness on the sound field characteristics of the platform and the waiting area is then studied.The research shows that when the wheel roughness is class A and the rail roughness is class A,the SPL of the platform and the waiting area is the smallest,i.e.95.1 d BA for the platform area,and 82.8 d BA for the waiting area;when the wheel roughness is class C and the rail roughness is class C,the platform and the waiting area have the highest sound pressure level,i.e.107.1 d BA for the platform area,and 86.8d BA for the waiting area.The effect of train speed on the acousic characteristics of the platform and the waiting area is studied.According to the research,when the train passes the platform at 250 km/h,the maximum SPL in the platform area is 103.2 d BA,and 88.9 d BA for the waiting area;when the train passes the platform at 60 km/h,the maximum SPL in the platform area is89.2 d BA,and 76.6 d BA for the waiting area.From the perspective of the noise source,the noise mitigation solutions are then analized.The effect of the embedded track on the sound field characteristics of the platform and the waiting area are analyzed as well.By using the embedded track,the maximum SPL of the platform noise is 90.4 d BA,which is 5.8 d BA lower than that of the traditional track;and 77.7 d BA for the waiting area,which is 6.1 d BA lower than that of the traditional track.The influence of using TMD rail on the sound field characteristics of the platform and the waiting area is then analized.The maximum SPL of the platform noise is 93.0 d BA,which is 3.2 d BA lower than that of the traditional track noise;the maximum sound pressure level of the waiting noise is 80.7 d BA,which is 3.1 d BA lower than that of the traditional track noise.From the perspective of the propagation path,the analysis of the influence of the sound insulation cover on the sound field characteristics of the platform and the waiting area is studied.The noise is reduced by 13.0 d BA by using the sound insulation cover.The maximum sound pressure level is 3.2 d BA which is greater than the platform reference noise limit.The maximum sound pressure level in the waiting area is 68.4 d BA,which is12.0 d BA lower than the maximum noise without a sound sound insulation cover.The thickness of the side wall of the sound insulation cover is optimized.By using the optimized sound insulation cover,the maximum SPL of the platform noise is 78.2 d BA at the platform,which is 18.0 d BA lower than maximum value of the noise without a sound insulation cover.The SPL in the waiting area is 60.4 d BA,which is 19.3 d BA lower than the maximum value of the noise without a sound insulation cover.When using the 7 mm and 8 mm thick sound insulation cover and the embedded track as the noise attenuation strategy,the maximum SPL in the platform area is 76.8 d BA and75.2 d BA,and the maximum SPL in the waiting area is 63.2 d BA and 60.4 d BA,which is below limit in the standard.When using the 8 mm thick sound insulation cover and the TMD track as the noise attenuation strategy,the maximum SPL in the platform area is 76.8 d BA,and the maximum s SPL in the waiting area is 63.4 d BA,which is below limit in the standard.