高速移动荷载作用下铁路隧道的动力响应分析

Dynamic Responses of Railway Tunnels under High-speed Moving Loads

从梁的强迫振动微分方程中得到移动荷载的处理方法,考虑了荷载的时间效应和空间效应,在开挖静力场的基础上对高速移动荷载下铁路隧道的动力响应进行分析.结果表明:结构最大动力响应发生在轮对经过测点后的某个时刻,略滞后于经过时刻点;结构竖向位移、加速度和动应力随着行车速度的提高而增大,其中仰拱动应力对行车速度最为敏感;高应力区主要集中在仰拱和边墙上,仰拱和边墙是隧道动力设计的薄弱部位;列车荷载作用下,结构破坏主要受抗拉强度控制.

In this paper, a method considering space-time effect to deal with moving loads has been obtained from the forced vibration differential equations of beams. And on the basis of the static stress states after construction, dynamic responsees of railway tunnels under high-speed moving loads have been analyzed. The calculation results show that the maxim dynamic responses of tunnels appear later than the time when the moving loads arrive; and the vertical displacement, acceleration and dynamic stress increase with load velocity. Especially, the dynamic stresses of inverts are affected furthest by load velocity. In addition, inverts and side walls are the dangerous position where high stresses exist and under the conditon of moving loads, the safety of tunnel linings is mainly controlled by their tensile strength.