【摘要】 地铁振动引起的环境问题备受人们的关注,特别是近年来,低频(<20Hz)振动对高精密仪器和设备、古建筑物等的影响已成为焦点。如何采取合理的减振措施将低频振动的影响降到最低是亟需解决的问题。在北京交通大学轨道减振与振动控制试验室,开展钢弹簧浮置板轨道和普通轨道低频振动试验;基于地表低频响应测试数据,结合"钢弹簧浮置板轨道-隧道-地层"和"普通轨道-隧道-地层"耦合的三维有限元数值模拟结果,采用回归分析的方法,研究地表低频响应受激振频率(1～20Hz)、距轨道水平距离(0～100m)和轨道埋深(10～30m)等因素的影响,推导出地表低频响应量分析公式。将公式预测的地表低频响应量的最大值分成II、II、II和IV四级响应带,进一步讨论响应带分布与轨道埋深、距轨道水平距离和轨道基频等关键因素的关系,从而为减少地铁振动的地表低频响应措施提供参考。更多还原

【Abstract】 Environmental vibrations induced by metro have been paid more and more attention in recent years,especially,the low-frequency(less than 20Hz) vibrations that might affect the operation of sensitive equipment and high-tech machinery and the safety of heritage buildings.How to adopt reasonable vibration countermeasures to minimize the impact of low-frequency vibrations is an urgent issue.Low-frequency vibration tests on the Steel Spring Floating Slab Track(SSFST) and the Ordinary Track(OT) in the Laboratory of Track Vibration Abatement and Control at Beijing Jiaotong University are carried out.Based on low-frequency measurement data on the ground,the coupled SSFST-tunnel-soil and OT-tunnel-soil systems are modeled,respectively,by using the three-dimensional finite element method to obtain the low-frequency ground response.Using regression analysis,the influences of the excitation frequency(1~20Hz),the distance(0~100m) from the track and the buried depth(10~30m) of the track on the low-frequency ground response are analyzed.An analysis formula for low-frequency ground response is derived.Maximum values of vibration acceleration level calculated from the analysis formula are divided into four-level response zones.The relationship between the distribution of response zones and critical parameters,including the buried depth of the track,the distance from the track and the basic frequency of the track,is elaborated.The study can be used as a reference to mitigate the low-frequency ground response due to metro induced vibrations.更多还原