Study On Vibration Reduction Effect Of Different Vibration Reduction Measures For Urban Rail Transit

Urban rail transit system has become an effective way to solve urban traffic congestion and reduce pollution by its advantages of speed,safety and environmental protection.Subway brings convenience,it also has a negative environmental impact.Especially the impact of noise and vibration,which has always been the focus of attention.This paper takes the Chengdu Urban Rail Transit as the background,and conducts on-site testing of the steel spring floating slab bed,longitudinal rail bed,vanguard fastener,Cologne egg fastener,and GJ-III fastener used in the vibration reduction section of Chengdu Metro,the vertical vibration acceleration values of the test tunnel walls in the common monolithic concrete bed and the adjacent damping section were compared within time domain and frequency domain.The actual damping effect of the vibration damping measures are analyzed from the time domain graph,the 1/3 octave curve and the frequency spectrum curve.The main work and research results are as follows.1.For fastener vibration reduction measures,the energy of the tunnel wall vibration of GJ-III fasteners,Cologne egg fasteners,and vanguard fasteners are mainly distributed in 50~70Hz and 175~185Hz,30~50Hz,30~50Hz and 130Hz~190Hz respectively.The effective damping range of the tunnel wall is 50~200Hz,40~150Hz and 31.5~200Hz respectively.The vibration reduction in the tunnel wall is 7.38 dB,6.99 dB and 17.15 dB respectively.2.For vibration reduction measures of the sleeper,the energy of the tunnel wall vibration in the longitudinal sleeper is mainly distributed in the range of 50-80 Hz.The effective reduction range of the longitudinal sleeper is 50-200 Hz,and the vibration reduction in the tunnel wall is 9.98 dB.3.For ballast vibration reduction measures,the energy of the tunnel wall vibration in the steel spring floating slab track is mainly distributed in the range of 80~110Hz,the effective reduction range of the teel spring floating slab track is 16~200 Hz,and the vibration reduction in the tunnel wall is 22.16.dB.4.The vibration reduction effectiveness from high to low is followed by steel spring floating slab bed,vanguard fastener,longitudinal rail bed,GJ-III fastener,and Cologne egg fastener.No matter what kind of reduction measures,they all show that the effect of high frequency vibration reduction is better than that of low-frequency vibration reduction,and the steel spring floating slab bed has the best vibration reduction effect at low frequencies.