列车荷载作用下地铁区间双层隧道模型试验研究

Research on Model Test of Double-decked Subway Tunnel under Train Vibration Loading

列车振动对双层隧道和近距离交叠隧道影响较大。以某地铁区间隧道为研究对象,对一单洞双层地铁区间隧道进行列车振动模型试验,选择合适的试验材料,确定隧道衬砌模型和地层材料参数。依照列车动荷载激振力公式,设计列车振动模型装置,解决动力响应模型试验中动荷载加载的问题。在进行静荷载作用下模型试验的基础上,完成双层隧道列车振动模型试验。测试、分析上行动载、下行动载和上下交会动载3种工况隧道结构的受力状态。研究表明:相对于动荷载,静荷载对结构应力状态影响更大,但在个别部位动荷载影响较大。在上下交会动载作用下,衬砌结构个别位置出现应力集中情况;加速度随着离振源距离加大而明显衰减;在一些测点的试验值与数值模拟结果基本吻合。

Vibration loads caused by passing trains affect near overlapping tunnels and tunnels with double deck structures enormously.A single tunnel with the double deck structure in a subway section was taken as the object of study.The train vibration model test of the above-said tunnel was carried out.Appropriate test materials were chosen.The tunnel lining model and stratum material parameters were determined.According to the formulas of exciting forces of dynamic train loads,the train vibration model device was designed and the problem of putting dynamic loads on the tunnel model was settled.The model test was carried out under static loads and then the model test was conducted under train vibration loads.The stresses and accelerations of the model structure were measured and the responses of the tunnel to the vibrations caused by trains running in the up direction,the down direction and up down crossing were analyzed.The results show as follows：Static loads produce greater influence on the stressed conditious of the tunnel structure in compariston with dynamic loads,but at some specific test,positions dynamic loads demonstrate greater influence;stress concentration occurs at some particular positions of the lining structure under the action of train vibrations in up down crossing;accelerations decay obviously with prolonging of the distance from the source of vibration;test results at some points agree with numerically simulated results basically.