列车速度对无碴轨道路基动力特性的影响

Influenced of train speed on dynamic characteristics of ballastless track subgrade

为了分析列车速度对无碴轨道路基动力影响,采用层状体系理论,结合有限元方法,建立无碴轨道路基层状有限元模型,考虑了列车荷载的不同速度对基床表层振动加速度、竖向动位移、动应力及其横向分布等路基动力特性的影响,研究了无碴轨道路基荷载作用下的力学行为。结果表明:列车速度对基床表层加速度的影响较大,竖向加速度随荷载速度的提高而增大;列车速度对基床表层动位移影响较小,速度每提高20 km.h-1,其值变化不大于0.05 mm;路基表层动应力随列车速度的提高呈现一定的波动趋势。计算结果与实测结果相似,证明了该模型的正确性。

In order to analyze the influence of train speed on the dynamic characteristics of ballastless track subgrade, a 3-D layer finite element model of the subgrade was establisbed by using layer system theory and finite element method, the different speed influences of train load on the vertical acceleration, vertical displacement, dynamic stress and its transverse distribution characteristics of the subgrade surface layer were considered, and the mechanical behaviors of the subgrade under train load were studied. It is observed that the vertical acceleration is obviously affected by train load speed, and the acceleration increases with train load speed raising; the dynamic displacement is little influenced by train load speed, and its change value is less than 0.05 mm when the speed increased by 20 km· h^-1 the dynamic stress presents a fluctuate trend with train load speed increasing. The result is similar to actual measure result, and approves the correctness of the model. 2 tabs, 11 figs, 16 refs.