高速铁路无砟轨道路基填料动力试验荷载分析

为获得高速铁路无砟轨道路基填料的动力试验参数,建立无砟轨道-路基系统三维有限元数值模型,模拟8辆编组的动车运行过程,结合实测数据分析轨道不平顺、列车速度、轴重、深度等因素对竖向动应力的影响。结果表明:路基动应力的一次加卸载过程,由同一转向架的两对轮载或相邻转向架的两对轮载共同完成;车速对动应力幅值影响较小,但引起路基承受荷载的作用频率呈线性增大;列车车轴重每增加10 kN,路基表面的动应力增加约0.97 kPa;无砟轨道路基承受荷载的作用频率为车长频率的1~4倍,且轨道不平顺没有改变荷载主频。依据动应力时程曲线特征及其频谱特征,采用全压正弦函数建立路基填料动力试验荷载表达式,加载频率可取车长频率的1~3倍。

Analysis of Dynamic Test Load on Filler of Ballastless Track Subgrade of High Speed Railway

In order to obtain dynamic test parameters for filler of ballastless track subgrade of high speed railway,a three-dimensional finite element model of the ballastless track-subgrade system is established to simulate the operation process of the eight-car train and the effects generated by track irregularities,train speed,axel load and subgrade depth on the vertical dynamic stress of the subgrade are analyzed based on the measuring data. The analyses indicate that one loading cycle of dynamic stress of subgrade is completed by two axles loading of the same bogie or four axles loading of the adjacent bogie. The dynamic stress amplitude changes little with the change of speed,and the frequency of the dynamic stress acting on subgrade increases linearly with train speed. The dynamic stress increases about 0. 97 kPa while the axle load increases by 10 kN. The frequency of the dynamic stress acting on subgrade is 1 to 4 times the fundamental frequency generated by the vehicle length,and the principal frequency of the dynamic stress is not affected by track irregularity. According to the characteristics of the dynamic stress time-history and the frequency,a load expression for dynamic test of subgrade filler is established with whole pressure sine function and the loading frequency may be 1 to 3 times the fundamental frequency generated by the vehicle length.