列车撞击荷载的有限元数值分析
Numerical Analysis of Train Impact Load with Finite Element Method

摘要： 为获得列车脱轨撞击荷载,分析列车撞击时盾构隧道的动力响应,建立了列车编组的三维撞击有限元模型,探讨了不同列车编组、不同撞击速度和撞击角度下列车近似撞击力时程曲线,分析了列车撞击力最大值和撞击时间与列车撞击速度和角度的关系,并将典型撞击荷载用于分析不同厚度二次衬砌管片衬砌的动力响应.结果表明:列车编组数量一定时,列车斜向撞击力最大值随撞击速度和撞击角度增大而增大;当撞击角度增大到7.5°后,撞击力作用时间随撞击速度增大而延长;根据列车撞击力最大值出现时刻不同,可将撞击力时程曲线划分为2类特征曲线,其中第1类特征曲线(撞击瞬间撞击力达到最大)总体上符合高斯多峰拟合公式,可用10个参数近似拟合.二次衬砌厚度增大能有效减小管片衬砌应力、速度、加速度等动力响应以及拉、压损伤区域.
Abstract: In order to obtain the train impact load on shield tunnel to investigate the dynamic responses of shield tunnel segment under train impact load, a 3D numerical analysis model for train formation was established to obtain the time-history curves of train impact force at different impact velocities, train formations and oblique impact angles. The maximum train impact force and impact duration as functions of impact velocity and impact angle were researched. Based on the representative time-history curves, the dynamic responses of shield tunnel with different thickness double lining caused by train impact load were investigated. The research result shows that when train formation is certain, the maximum train impact force increases with the increases of impact velocity and impact angle; when impact angle is larger than 7.5°, impact duration extends with the increase of impact velocity. From different times at which the maximum train impact force appears, the time-history curves of train impact force can be divided into two kinds of characteristic curve, and the first kind of characteristic curve with the maximum impact force appearing at the impact moment is in accordance with the Gauss multiple peak fitting formula, and 10 parameters can be used to achieve its approximate fitting. To increase secondary lining thickness can effectively reduce the dynamic responses of external segment lining under train impact load such as stress, velocity and acceleration as well as tension and compression damage zones