列车通行条件下高速铁路人行天桥表面压力脉动研究

列车高速通过人行天桥底部正线时,桥体表面受到较大的瞬变气动荷载作用,引发桥体结构振动并影响到桥上旅客的舒适性以及桥体结构的疲劳寿命。通过数值仿真计算研究单列高速动车组以不同速度通过人行天桥时,天桥表面的气动载荷空间变化规律。结果表明:在本文计算条件下,车桥系统周围的流场达到了自模拟区,列车运行速度增加不会对天桥表面的气动压力系数造成较大影响;列车通过人行天桥底部时,天桥迎风侧以及底部依次出现压力先上升后迅速下降再上升的头波、中间车辆通过时的负压区域、以及压力先下降后迅速上升再逐渐衰减为0的尾波,桥底越靠近中心处压力变化峰峰值越大;天桥迎风侧仍然是对应于正线的测点头波压力变化峰峰值最大,同一测线上测点越高压力变化峰峰值越小。

Study on Surface Pressure Fluctuation of Railway Pedestrian Overpass Under High Speed Train Passage Conditions

When the train passes through the main line under the pedestrian overpass at high speed,the transient pressure causes large transient pneumatic loads on the surface of the overpass,which causes the vibration of the overpass structure and affects the comfortness of the passengers on the overpass and the fatigue life of the overpass.By the means of numerical simulation,the spatial variation laws of pneumatic load were studied when a single high speed EMU passes through the pedestrian overpass at different speeds.The results show that the flow field around the train-overpass system reaches the self-simulation zone,the increase of the train speed does not affect the aerodynamic pressure coeff icient of the overpass surface greatly.When the train passes through the pedestrian overpass,the windward side and the bottom of the overpass appear in turn the head wave with pressure f irst rises then decreases rapidly and then rises,the negative pressure area while the middle EMU passing through,and the tail wave with pressure f irst decreases then rises rapidly and gradually decreases to zero.For the bottom of the overpass,the closer the measurement points is with the train passing through the pedestrian overpass,the greater the peak pressure change.For the windward side,there is still a law that the peak pressure change of the head wave at the measurement points corresponding with main line is the largest.On the same measurement line,the higher the measurement point is,the smaller the peak pressure change is.