地铁列车运行诱发低频振动控制数值研究

Numerical Study on Low Frequency Vibration Control Induced by Operation of Subway Train

地铁列车运行诱发的低频振动问题受到人们的广泛关注,对于低频振动的控制研究具有重要意义。采用移动激振力函数来模拟轮轨之间相互作用力,建立轨道-隧道-地层三维动力有限元模型。核心思想是通过降低地层中能量传递密度的方式来减小低频振动,首先分析地铁列车运行诱发的地层和地表动力响应规律,揭示低频振动的传播衰减机理。之后通过普通整体道床轨道和钢弹簧浮置板轨道两个不同的轨道型式,系统地分析普通整体道床轨道中隧道衬砌参数和道床参数对地表低频振动的影响规律,对钢弹簧浮置板轨道进行优化,增大底板的刚度和厚度,研究优化后底板参数和隔振器排列方式对地表低频振动的控制效果。计算结果表明:低频部分随着与隧道纵向轴线距离的增加,在地层和地表均衰减较慢;普通整体道床轨道中道床刚度和高度、隧道衬砌刚度均对低频振动的影响较大,而隧道衬砌厚度对低频振动的影响较小;钢弹簧浮置板轨道中随着底板刚度和长度的增加,低频振动的控制效果越好,隔振器数量越少,越有利于低频振动的控制。

Low frequency vibration induced by the operation of subway train has been widely con-cerned by people,and it is of great significance to the research of low frequency vibration control.This study establishes a three-dimensional dynamic finite element model for rail-tunnel-stratum utilizing a moving excitation force function to simulate the interaction forces generated by wheel-rail contact.The core idea of this paper is to reduce low frequency vibration by reducing energy transfer density in the stratum.Firstly,the dynamic response law of ground and surface induced by subway train operation is analyzed to reveal the propagation and attenuation mechanism of low frequency vibration.Then,through two different track types of ordinary integral track bed and steel spring floating slab track,the effects of tunnel lining parameters and track bed parameters on low-frequency vibration of the ground surface in ordinary integral track are systematically analyzed,and the steel spring floating slab track is optimized to increase the stiffness and thickness of the bottom board.The control effects of optimized bottom board parameters and isolator arrangement on low-frequency ground surface vibration are stud-ied.The calculation results show that the low-frequency part decays slowly in both stratum and surface with the increase of the distance from the longitudinal axis of the tunnel.The stiffness and height of track bed and the stiffness of tunnel lining have great influence on the low frequency vibration,but the thickness of tunnel lining has little effect on low frequency vibration.With the increase of the stiffness and length of the bottom board,the control effect of low frequency vibration becomes better,the few-er the number of isolators,the better the control of low frequency vibration.