减振扣件对地铁隧道-地表振动特性影响分析

研究目的:不同减振扣件对地铁隧道-地表环境振动的减振效果特性有所差异,列车运行引起的隧道和地表的振动在时域和频域上有较大区别,目前对减振扣件减振效果评价多采用不同断面进行对比分析,但其结果会受到隧道断面周围结构的影响。基于此,本文通过对普通扣件和减振扣件下列车运行引起的隧道结构及地表振动进行现场实测分析,并建立车辆-轨道-隧道-大地耦合动力分析数值模型,研究减振扣件对隧道结构-地表的减振效果。研究结论:(1)减振扣件能有效控制道床和隧道壁上的振动响应,当采用减振扣件后,道床上峰值变小且峰值出现频段向低频偏移,隧道壁上减振扣件在卓越频率范围内出现振动放大现象;(2)地面测点的振动加速度峰值和Z振级随距离振源的位置增加呈现出减小的趋势,但是在15~30 m范围内出现增大的现象,说明在该区域范围内出现振动放大的现象,但放大区间有所不同,应根据具体工程选择合适的扣件;(3)地面同一测点振动加速度峰值和Z振级呈现出W形的变化趋势,因此在进行地面振动控制时应充分考虑控制点所处位置,根据具体情况采用合理的控制措施;(4)本研究成果可为轨道交通中隧道和地表振动控制措施选择提供理论依据。

Analysis of Influence of Damping Fasteners on Vibration Characteristics of Metro Tunnel-Surface

Research purposes:The vibration reduction effect characteristics of different vibration reduction fasteners on the subway tunnel and surface environment vibration are different.The vibration of the tunnel and the surface caused by the train operation is quite different in the time and frequency domain.At present,the vibration reduction effect evaluation of the vibration reduction fasteners mostly uses different sections for comparative analysis,and the results will be affected by the structure around the tunnel section.Based on this,this paper analyzes the tunnel structure and ground vibration caused by the train running under the ordinary fastener and damping fastener,and establishes the numerical model of vehicle-track-tunnel-earth coupling dynamic analysis to study the damping effect of damping fastener on the tunnel structure and ground.Research conclusions:(1)The vibration response of ballast and tunnel wall can be effectively controlled by the damping fastener.When the damping fastener is used,the peak value on the ballast bed becomes smaller and the frequency band of the peak value shifts to the low frequency.The vibration amplification phenomenon appears in the predominant frequency range of the vibration reduction fastener on the tunnel wall.(2)The peak value of vibration acceleration and Z vibration level of the ground measurement point decrease with the increase of the distance from the vibration source,but they increase within the range of 15 m^30 m,which indicates that the phenomenon of vibration amplification occurs within the range of this area,but the amplification range is different,so appropriate fasteners should be selected according to the specific project.(3)The peak vibration acceleration and Z vibration level of the same measuring point on the ground show a W-shaped trend.Therefore,when controlling the ground vibration,the position of the control point should be fully considered and reasonable control measures should be taken according to the specific situation.(4)The research results can provide theoretical basis for the selection of vibration control measures of tunnel and ground in rail transit.