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基于无限元人工边界建立了既有线有砟轨道路桥过渡段路基在动荷载作用下的三维有限元模型,模型考虑路桥过渡段倒梯形的结构形式,利用一系列移动轮载扩散到路基面的动面力模拟编组列车通过过渡段产生的动荷载,分析了既有线列车通行速度在现行速度80km/h和目标速度160km/h范围内变化时,路桥过渡段在动荷载作用下的路基动力响应规律。研究发现:列车速度从80km/h提升至160km/h后,路基面动应力峰值将增大20%左右;相比普通路基,路桥过渡段路基在提速条件下会产生较大的动应力;路基面动应力沿基面以下深度方向呈指数形态衰减。
Based on the infinite artificial boundary, a three-dimensional finite element model of existing subgrade under the dynamic load is established for the existing transitional sections of ballastless track road and bridge. The model takes the form of inverted trapezoid in the transitional section of road and bridge into consideration, and uses a series of moving wheel- Surface force simulates the dynamic load generated by the train transition through the transition section. When the existing train speed changes within the range of 80km / h and 160km / h, the dynamic response of roadbed under the dynamic load is analyzed . The results show that when the train speed is increased from 80km / h to 160km / h, the peak dynamic stress at the subgrade will increase by about 20%. Compared with ordinary subgrade, the subgrade at the transitional section of road and bridge will generate greater dynamic stress under the conditions of speed increasing. Surface dynamic stress attenuates exponentially along the depth below the basal plane.