地铁隧道壁面压力特性实车试验研究

Field experiments study on pressure characteristics of subway tunnel wall

采用实车试验方法,通过重复性分析和不确定度分析证明测试方法的重复性和可靠性,研究地铁隧道内的压力波传播机理,分析不同风井条件和车速等级下隧道壁面瞬变压力的分布规律,得到隧道内衬砌和附属设施的压力标准参考值。研究结果表明:隧道内压力幅值受列车速度、运行方向和风井条件的影响;隧道壁面压力系数峰峰值与列车速度的平方成正比;进出隧道引起的隧道内最大压力系数峰峰值分别为4.55和4.01;当列车以95 km/h运行时,作用于隧道衬砌及附属设施的最大压力峰峰值为2.01 kPa。与封闭风井相比,开放风井可减少风井位置处的压力变化,显著降低风井区域的初始压缩波压力系数正峰值和循环周期,在AN-5位置(距风井5 m的北侧测点)的初始压缩波压力系数正峰值和循环周期分别降低了78.5%和83.4%;但对于列车前进方向一侧,距风井25~50 m的隧道壁面反而产生增压效果;由于隧道壁面的增压区域相对较小,高速列车运营条件下的通风风井依然有利于隧道内的泄压通风,建议风井设置为开放状态。研究成果可为地铁列车的运营维护和隧道附属设施的设计提供参考。

The propagation mechanism of pressure waves was studied by the filed experiments.The repeatability and reliability of the test method were proved by repeatability analysis and uncertainty analysis.The mechanisms underlying pressure distributions along the tunnel wall under different airshaft conditions and train speeds were analyzed.The reference value of pressure standard of lining and auxiliary facilities in the tunnel was obtained.The result shows that the pressure amplitude in the tunnel is affected by train speed,running direction and airshaft conditions.The peak value of the maximum pressure on the tunnel wall is directly proportional to the square of the train speed.The maximum peak-to-peak values of pressure coefficient are caused by the train entering and exiting the tunnel are 4.55 and 4.01 respectively.When the train runs at 95 km/h,the maximum peak-to-peak values of tunnel lining and auxiliary facilities shall be 2.01 kPa.Compared with the closed airshaft,the opened airshaft can reduce the pressure change at the airshaft position,and significantly reduce the positive peak value and cycle period of the initial compression wave in the airshaft zone.The positive peak value and cycle period of the initial pressure coefficient at AN-5(the North measuring point 5 m away from the airshaft)are reduced by 78.5%and83.4%,respectively.However,for one side of the train in the forward direction,the tunnel wall 25 m to 50 m away from the airshaft produces pressurization effect instead.As the pressurization area on the tunnel wall is relatively small,the ventilation shaft under the operation condition of high-speed train is still conducive to pressure relief and ventilation in the tunnel.It is recommended to set the airshaft in an open state.The research results can provide reference for the operation and maintenance of subway trains and the design of tunnel ancillary facilities.