重载铁路隧道基底结构动应力分析

Dynamic stress analysis of heavy haul railway tunnel base structure

以某重载隧道工程为背景,利用有限差分软件进行数值模拟,以人工激振函数模拟列车振动荷载,研究25t、27t、30t轴重列车荷载作用下隧道基底结构的动力响应。结果表明:随着列车轴重的增大,基底各部位的动压应力呈非线性增长,且增加幅度逐渐扩大;动压应力自道床层依次向下随深度的增加而不断减小,30t轴重作用下线路中心处动压力从道床上表面传至道床下表面衰减50.7%,传至仰拱上表面衰减54.1%,传至仰拱下表面衰减10.3%,在道床层和填充层内动应力衰减幅度较大,在仰拱结构内衰减幅度较小。

Based on the background of a heavy-load tunnel project,the finite difference software was used for numerical simulation,and the vibration load was simulated by artificial excitation function.The dynamic response of tunnel basement structure under the load of 25t,27t and 30t axle load trains was studied.The results show that with the increase of axle load,the dynamic compressive stress of each part of the base increases nonlinear,and the increasing range gradually expands.The dynamic stress decreases from the passage bed to the lower surface of the passage bed,from the upper surface of the invert to the upper surface of the invert,and from the lower surface of the invert to the lower surface of the invert by 50.7%,54.1%,and 10.3%.The attenuation of the dynamic stress is larger in the passage bed and filling layer,but smaller in the invert structure.