地铁钢弹簧浮置板轨道的减振效果分析

Analysis on the Vibration Attenuation of Metro Steel Spring Floating Slab Track

应用ABAQUS软件建立列车-轨道-隧道-土层的动力学模型，研究钢弹簧浮置板的减振效果。在地铁列车以20m·S^-1速度运行条件下，浮置板的振动加速度峰值（15irk·S^-2）远大于普通轨道；铺设浮置板后隧道拱顶和地表的振动加速度峰值分别为0．07和0．005m·s^-2，远小于普通轨道。频域分析表明：浮置板的振动频率在400Hz以上频段衰减很大，而100Hz以内低频成分的振动能量明显增强；浮置板轨道对于隧道拱顶在400-800Hz、地表在20-80Hz频段内的减振效果明显。1／3倍频程分析表明：浮置板的分频振级最大增量为22dB（中心频率为10Hz）；铺设浮置板后隧道拱顶的最大减振量为18dB（中心频率1016Hz），地表的分频最大减振量为6dB（中心频率63Hz）。Z振级分析表明：铺设浮置板后隧道拱顶和地表处的减振量分别为24和25dB，在25-80Hz频段的减振效果最好；因浮置板自振频率处于20Hz以下的低频范围，能够吸收中高频振动、放大自身低频振动，所以具有阻高频、放低频的减振特性。

The train-track-tunnel-soillayer dynamic model was established by software ABAQUS to study the effect of vibration attenuation of steel spring floating slab. The peak acceleration amplitude of floating slab （15 m· s^-2） is much larger than that of general track when the train runs at the speed of 20 m · s^-1. The peak acceleration amplitudes of tunnel wall top and ground surface are 0.07 and 0. 005 m · s^-2 , which are much smaller than that of general track. Frequency-domain analysis shows that the vibration attenua- tion of the frequency band above 400 Hz of floating slab is very large and the vibration below 100 Hz in- creases obviously. The vibration attenuation effect of floating slab track is obvious at tunnel wall top in 400-800 Hz band and ground surface in 20-80 Hz band. The analysis of 1/3 octave shows that the maxi- mum increment of fractional-frequency vibration of floating slab is 22 dB （at center frequency of 10 Hz）. After laying floating slab, the maximum vibration attenuation amount is 18 dB （at center frequency of 1016 Hz） at tunnel wall top and the maximum vibration attenuation amount of the fractional-frequency is 6 dB （at center frequency of 63 Hz） at ground surface. The analysis of Z vibration level shows that, after laying floating slab, the vibration attenuation is 24 dB at tunnel wall top and 25 dB at ground surface. The vibra- tion attenuation performs best in 25-80 Hz band. Because the natural frequency of floating slab is below 20 Hz, vibration in intermediate and high frequency band can be absorbed, and the low frequency vibration of itself can be amplified. So it has the quality to decrease that in low frequency band. vibration in high frequency band and let through