地铁振动荷载作用下场地动力响应及振动衰减规律研究

Research on Site Dynamic Response and Vibration Attenuation under the Vibration Loading of Subway

地铁列车运行引起的场地振动对临近建筑、精密仪器等带来不可忽视的影响。为了研究场地在地铁运行振动荷载作用下的动力响应规律,基于ABAQUS软件建立了地铁隧道-土相互作用系统的二维有限元模型,并通过现场试验监测数据验证了模型的有效性。在此基础上,通过对场地表面振动峰值速度和加速度时程分析,研究了隧道埋置深度、土体阻尼比、土体不均匀性对场地地表振动特性及衰减规律的影响。研究结果表明:在一定范围内,土体表面的动力响应随着隧道埋置深度、土体阻尼比的增大而减小;不同土质条件下的场地地表的动力响应有一定的差别,但随着距离的增大,差别逐渐缩小。基于上述参数分析,采用MATLAB对峰值速度衰减曲线进行拟合,给出了场地振动衰减预测公式,可为振动敏感建筑场地的选择提供参考。

The vibration of the site has a significant impact on adjacent buildings and precision instruments due to the subway operation.A two-dimensional finite element model of the subway tunnel-soil interaction system was established based on the ABAQUS software to study the dynamic response of the site under the vibration loading of the subway,and its validity was verified by field test monitoring data.Then the effects of tunnel burial depth,soil damping ratio,and soil non-uniformity on the soil surface vibration characteristics and attenuation laws are analyzed by analyzing the peak speed and acceleration time history of the site surface vibration.The results show that the dynamic response of the soil surface decreases as the increase of the tunnel burial depth and the damping ratio of the soil within a certain range;the dynamic response of the ground surface of the site under different soil conditions has some difference,but the differences gradually decrease with the increase of the distance.Based on the above parameter analysis,MATLAB is used to fit the peak velocity attenuation curve,and the prediction formula of site vibration attenuation is given,which provides a reference for the selection of vibration-sensitive building sites.