列车振动荷载作用下公轨合建隧道及周围土体动力响应特性研究

Study on the dynamic response characteristics of road-metro tunnels and surrounding soil under train vibration loads

为了研究列车振动荷载作用下公轨合建隧道及周围土体的动力响应特性,采用模型试验与数值模拟相结合的方法,基于时频分析研究隧道管片和内部结构的动力响应特性以及振动波在地层中的衰减特性。研究结果表明:列车荷载作用下全频域范围内,隧道管片结构动力响应随着频率的增大而增大,而内部结构上部车道动力响应表现为随频率的增大先增大(0~140 Hz)后减小(140~200 Hz)。就不同位置动力响应衰减幅度而言,上部车道最大,其响应平均衰减幅度为20.05 dB,相应地时域上峰值加速度的衰减幅度为72.6%。此外,考虑列车振动荷载的移动效应会使隧道结构的动力响应增大,移动荷载作用下道床处峰值加速度增加了约105%,内部结构侧壁处增大了41.9%,侧壁与上部车道连接处增大了47.3%,上部车道中心处增大了22.3%。单次列车振动荷载作用过程中隧道结构的最大位移发生于拱底,其峰值为3.85 mm。

In order to study the dynamic response characteristics of road-metro tunnels and surrounding soil under train vibration loads,based on the time domain and frequency domain analysis,the dynamic response characteristics of tunnel segments and internal structures,as well as the attenuation characteristics of vibration wave in the stratum are studied by using the method of model test combined with numerical simulation.The results show that in the full frequency domain under train loads,the dynamic response of tunnel segments increases with the frequency,while the dynamic response of the upper lane of the internal structure first increases(0-140 Hz)and then decreases(140-200 Hz).As for the attenuation amplitude of dynamic response at different positions,the upper lane is the largest,its average attenuation amplitude of response is 20.05 dB,and the attenuation amplitude of the peak acceleration in the corresponding time domain is 72.6%.In addition,the dynamic response of the tunnel structure will increase because of the moving effect of the train vibration load.Specifically,the peak acceleration at the track bed increases by about 105%,the side wall of the internal structure increases by 41.9%,the connection between the side wall and the upper lane increases by 47.3%,and the center of the upper lane increases by 22.3%.In the process of single train vibration load,the displacement of the tunnel structure meets its maximum at the arch bottom,with a peak value of 3.85 mm.