列车荷载作用下隧道振动数值模拟研究

Numerical Simulation of Subway-Induced Vibration of a Tunnel

在考察地铁列车引起周围环境振动的问题时,一般把列车-轨道看作振源并单独研究,轨道底部反力则作为输入作用在结构上。文章在建立"列车-轨道"振源模型时,使用三角级数来模拟列车荷载,将钢轨模拟为周期支撑在具有一定刚度和阻尼支座上的有限长Timoshenko梁,在时域内进行数值积分得到轨底反力。建立"隧道-地层"模型时选取了一定宽度和深度的土层,并赋予各层土体不同的刚度和阻尼;另外在土体模型边界处设置粘弹性约束来缓解波的反射现象。最后通过现场实测数据和数值模拟结果进行对比,来验证所建立模型的有效性。

The vehicle-track system is usually viewed as vibration source and studied separately for the subway-induced environmental vibration,since the track bottom force corresponds to load input on the surrounding structure. Within the ＂vehicle-track＂ vibration source model, the vehicle is modeled using trigonometric series, while the track is modeled as a Timoshenko beam with finite length, which is periodically supported on parallel spring and damper. Track base counter force is obtained by numerical integration of the vibration source model in the time domain. Soil with finite width and depth is selected when building the ＂tunnel-ground＂ model, while each soil layer is modeled with respective stiffness and damping. Besides, viscous elastic boundary is adopted to mitigate wave reflection. simulation results were finally compared with the field test results to validate the effectiveness of the proposed model.