高速铁路路基动力反应的有限元分析

FINITE ELEMENT ANALYSIS FOR DYNAMIC RESPONSE OFROADBED OF HIGHSPEEDRAILWAY

通过引入波传导单元和完全的能量传递边界，本文用有限元法分析了铁路路基在高速列车作用下的动力反应；它利用波动的可迭加性，首次将列车车辆的全部轮载加以考虑；并着重讨论了车速、地基刚度及车辆振动等所带来的影响。分析结果认为：①针对竖向动位移，路基存在一个临界速度，地基刚度越小，临界速度越低；②竖向加速度随车速的提高而加速增长，随车辆振动频率的升高呈线性增长；③在道碴与基床之间铺设一层混凝土板对路基的动力反应有显著的降低效果。

By introducing wave-transmitting elements and complete energy-transmitting boundaries,a finite element method is used to analyze the dynamic response of the roadbedunder high-speed train loads. It is for the first time to take into account all wheel-loads byusing the superposition of waves.Furthermore,the effect of the train speed,complex modulus of the subgrade,and vibrating conditions of the vehicles are discussed.The analytical resuIts indicate that:(1)A critical velocity for the vertical displacement of roadbed is actuallyin existence,The weaker the subgrade,the lower will be the critical velocity.(2)The vertical acceleration has a tendency to increase acceleratively as the velocity increases,and to increase linerly as the frequency of the vibration increases,(3)The dynamic response can bereduced significantly by installing a concrete slab between the ballast and the roadbed。