Research On Environmental Vibration Induced By Subway On Viaduct Of Chengdu Metro Line 2 East Extension Line

With the improvement of urbanization rate in China,urban rail transit has been vigorously developed.The subway as China’s current use of the largest urban rail transit system,with the advantage of large transport capacity,high-speed security,environmental pollution and so on.But the subway in giving people travel convenience at the same time,due to vibration pollution problems to the residents along the troubled,so that people’s production and life by a large degree of interference.Because the elevated section has the advantages of short construction time,low input cost and low operation and maintenance cost,So the proportion of the suburbs in the city is very high,which is more likely to cause the masses to be disgusted.Therefore,the research on the environmental vibration of the subway elevated section is worthy of attention.Based on the specific environmental conditions,this paper conducts field tests on the viaduct environmental vibration of the east extension line of Chengdu Metro Line 2,and Explore it’s Environmental Vibration Characteristics.This thesis analyzes the measured data of YDK46 + 700 viaduct of the east extension line of Chengdu Metro Line 2,obtains the vibration characteristics and attenuation law of X,Y and Z.This thesis uses Origin Pro9.0 software to fitted the measured Z vibration level data to obtain empirical formula of environmental vibration attenuation.1.With the distance from the center line increases;X and Z direction of the vibration acceleration amplitude showed a decreasing trend,but Y appeared to enlargethesituation,the overall trend is increased first and then reduced,It may be due to the superposition of different vibrational waves during propagation.But at the same distance from the center line,the acceleration amplitude of the vibration is Z and Y is much larger than the X direction.2.The vibration spectrum can be divided into three frequency bands,low frequency band 1～20Hz,middle band 20～50Hz,high frequency band 50～125Hz.In the whole vibration band,the vibration of the high frequency band produces the most energy,and the closer the vibration source,the higher the proportion of the high frequency vibration.When the distance from the center line increases,the impact of high-frequency vibration will gradually become smaller,The proportion of intermediate frequency and low frequency vibration will gradually increase.And from the acceleration attenuation situation,the high-frequency peak attenuation of the fastest,followed by the frequency,and little change in low frequency.3.According to the measured data of multiple trains,calculate the average Z-level,And fitting out the formula for the vibration level of the elevated section of Chengdu Metro Line 2 with distance,Which can provide a reference for the prediction of environmental vibration of similar subway.