地铁产生的环境振动及轨道结构减振分析

Analyses of Subway Induced Environment Vibration and Vibration Reduction of Rail Track Structure

以南昌地铁1号线八一广场段为工程背景,对轨道—隧道—大地的三维有限元模型进行动力学分析。分别建立三种道床模型:整体道床、弹性支承块道床和钢弹簧浮置板道床。以振动加速度、1/3倍频程振动加速度级和Z振级作为评价指标,比较不同轨道结构下隧道壁及地面的振动响应。随之减振道床支承刚度的变化,分析道床的自振频率对减振效果的影响。计算表明:列车引起的地面振动主频在40 Hz附近;减振道床的自振频率对减振效果有较大影响;钢弹簧浮置板道床减振效果明显优于弹性支承块道床。

Taking the part of subway line 1 in Nanchang Bayi square area as the engineering object,the threedimensional finite element model of a rail-tunnel-ground system is constructed and its dynamic responses are calculated.Three kinds of track bed models,monolithic track bed,elastically supported block track bed and steel-spring floating-slab track bed,are constructed.Taking vibration acceleration,one-third octave vibration acceleration level and Z vibration level as evaluation indexes,the vibration responses of the tunnel wall and ground surface with different track structures are compared.Considering the support stiffness change of the vibration-reduction track bed,the influence of natural frequency on the vibration reduction effect is analyzed.The study shows that the main frequency of ground surface vibration induced by train is near 40 Hz.The natural frequency of vibration for the vibration-reduction track bed has a great influence on the vibration reduction effect.The vibration reduction effect of the steel-spring floating-slab track bed is much better than that of the elastically supported block track bed.