摘要
基于近波场非连续屏障理论,提出孔列道床这一新型减振轨道方案,分析其减振的理论依据及减振性能。选择SH波分析近源波场的屏障隔振问题,求解SH波作用在单一圆柱形孔槽散射解析解和孔列衍射波场的表达式。可知屏障能够造成能量的散射,加大入射波的几何阻尼,为原入射波与散射波相互叠加和消减提供了可能。而孔列屏障会引起衍射效应,可降低屏障后区域的振动能量从而达到减振目的。建立"轨道-隧道-地层"三维动力有限元模型,对比分析圆形隧道中单排孔列道床与普通整体道床两种工况下隧道壁及地表的振动响应。两种工况下隧道壁的振动加速度时程、频谱及1/3倍频程曲线规律相似,在20Hz以上频段,孔列道床工况下的加速度级略小于普通工况,差值在50Hz附近达到最大。隧道壁及地表拾振点的插入损失均在20Hz以上频段为正,且隧道壁处插入损失小于地表各拾振点处。结果表明孔列道床并未改变轨道系统的特性,在50Hz以上频段减振效果较明显,并在距离屏障一定距离外能够发挥出更优的减振作用。
Based on the discontinuous barrier theory for near-field waves,a new type of vibration mitigation track,called a row-layout cavity-ballastless track(RLCBLT),is proposed and its mitigation principle and performance are analyzed.First,shear waves with horizontal displacement were used to investigate the barrier vibration isolation and analytical solutions of the scattering effects of a single hole.Then,formulations of the diffraction wave field of a hole group were derived.The barrier can scatter the vibration energy and enlarge the geometric damping of the incident wave,thus providing the possibility of superposing and reducing the incident and scattering waves.RLCBLT can cause a diffraction effect that reduces the vibration energy in the area behind the barrier.Next,a track-tunnel-soil three-dimensional dynamic-finite-element model was established to calculate and compare the dynamic responses at the wall of a circular tunnel and at the ground surface under two conditions:a single line RLCBLT and a regular track.Under these two conditions,the profiles of the accelerations in the time domain,the frequency domain,and the one-third octave band are similar.Above 20 Hz,the acceleration level under the RLCBLT condition is slightly lower than that under the regular track condition,with the maximum difference appearing at 50 Hz.The insertion loss of the receiver point at the tunnel wall and at the ground surface is positive above 20 Hz,with the insertion loss of the former bring lower than that of the latter.The characteristics of the track system are not altered by the application of RLCBLT,and its vibration mitigation effect is moreobvious above 50 Hz.RLCBLT can better mitigate train-induced vibrations beyond a certain distance from a barrier.
作者
孙晓静
刘博
徐利辉
Sun Xiaojing;Liu Bo;Xu Lihui(Key Laboratory of Urban Underground Engineering of Ministry of Education,Beijing Jiaotong University,Beijing 100044,China;School of Civil Engineering,Beijing Jiaotong University,Beijing 100044,China;Tianjin Railway Technical and Vocational College,Tianjin 300000,China)
出处
《土木工程学报》
EI
CSCD
北大核心
2021年第S01期97-103,共7页
China Civil Engineering Journal
基金
国家自然科学基金(51778049,52178404)
关键词
城市轨道交通
孔列道床
非连续屏障隔振
减振性能
数值模拟
urban mass transit
row-layout cavity-ballastless track
discontinuous barrier theory
vibration mitigation performance
numerical simulation
作者简介
孙晓静(1978—),女,博士,副教授,博士研究生导师。主要从事轨道交通环境振动影响及隧道结构动力特性等方面的研究;通讯作者:刘博(1989—),男,硕士,讲师。主要从事隧道工程减振与施工技术等方面的研究,E-mail:36177447@qq.com;徐利辉(1993—),男,博士研究生。主要从事轨道交通环境振动控制及隧道动力学等研究。
