地基加固对隧道下穿铁路路基车致动力响应的影响

通过现场测试及数值模拟,研究了地表铁路行车作用下地铁隧道下穿铁路路基系统的动力响应规律,分析了下穿节点地基加固体弹性模量、深度等参数对地表振动及地铁隧道结构的影响。研究结果表明：车致地表振动频率由列车轮对分布、轨枕间距及行车速度共同决定;地基加固增加了下穿系统的车致振动响应,降低了高频振动的衰减速度;提升加固体模量,会增大地表振动加速度;加固深度提升至隧道底部可有效降低隧道的附加动应力。

Dynamic Response of Foundation Reinforcement to Underpass System Under Train Load

Field tests and numerical simulation were carried out to study the dynamic response of the underpass system of tunneling beneath the railway embankment under the train load. A finite element model has been established to study the effect of the elastic modulus of the reinforced soil and reinforcement depth on the vibration acceleration of ground surface and additional stress of tunnel crown. The results show that the main vibration frequencies of ground surface are caused by the periodic distribution of train wheels, sleeper spacing and specific driving speeds. The amplification of ground surface vibration and the reduction of the attenuation rate of high frequency vibration appear by the reinforced foundation. The vibration acceleration of the ground surface increases with the increase of elastic modulus of the reinforced soil. The reinforcement depth of the foundation exceed to tunnel buried depth, which can effectively reduce the additional dynamic stress of the tunnel.