Vibration Reduction Effect and Displacement in Multi-level Vibration Reduction Prefabricated Track Bed
In the Zhangpeng section of the Qingdao New Metro Line 4,the vibration and displacement responses of prefabricated track beds with high-and medium-level composite vibration reduction pads,as well as ordinary track beds,were tested at a speed of 70 km/h to examine the vibration reduction effects of different composite levels.Using the root mean square value of the frequency division vibration level of the lead hammer Z vibration level and transmission loss of the Z vibration level,a comprehensive evaluation was performed.The vibration characteristics of tracks on prefabricated track beds and ordinary track beds,equipped with two different damping levels of composite damping pads,were then compared and analyzed in time and frequency domains.The results showed that:(1)the tunnel wall frequency division vibration levels of the three different damping types of track bed tracks reached their maxima at 50-80 Hz.Compared with ordinary track beds,the damping effects of high and medium damping track beds(average root mean square difference of frequency division vibration levels)were 13.9 dB and 8.5 dB,respectively;The Z-level transmission loss values between the track bed and tunnel wall were 45.8 dB and 35.1 dB,respectively;(2)During actual operation,the vertical displacement of the high,medium damping track bed,and ordinary track bed were 2.298 mm,0.265 mm,and 0.058 mm respectively,while the lateral displacement of the track bed was 0.058 mm,0.025 mm,and 0.019 mm,respectively.The multilevel vibration reduction universal prefabricated track bed exhibited obvious vibration reduction effects for vibrations exceeding 20 Hz and facilitated freely selecting and changing the vibration reduction level based on different needs.This offers certain guiding significance for the development of universal vibration reduction prefabricated track beds.
NETL
NSTL
万方数据
维普
