【摘要】 无砟轨道与深埋式桩板结构低路堤形成的"上刚-中柔-下刚"结构体系,导致基床受力加大、状态复杂,因此有必要针对刚性地基低路堤长期动力特性进行专门的动力试验研究。通过京沪高速铁路试验段模拟列车动荷载的原位循环激振试验,测定低路堤不同断面、不同深度处的动力响应,分析刚性地基上低路堤长期动力特性。结果表明:刚性地基上低路堤动力响应在激振70万次后趋于稳定,各典型断面动位移幅值均小于0.1mm,路基面动刚度值介于280~350MN/m之间,断面间刚度差异较小;激振150~200万次后累积变形为0.3~0.4mm;由轨道结构、基床和桩板结构、地基构成的"上刚-中柔-下刚"结构体系具有良好的长期动力稳定性。更多还原

【Abstract】 The structural system of "rigid-soft-rigid" in order of depth formed by the unballasted track and the low embankment of deeply buried pile-board structure increases the complexity of the subgrade stress state.It’s necessary to conduct special dynamic test to study the dynamic characteristics of the low embankment on this rigid foundation.Dynamical responses of low embankment in different depths and sections were measured in the in-situ test of cycle vibration on test sections of Beijing-Shanghai high speed railway.Analyses of the long-term dynamic characteristics of low embankment on rigid foundation were carried out on the simulated train dynamic loads.The results show that the dynamic response of low embankment on the rigid foundation gradually comes to stable after 70 million times of vibration,with dynamic displacement amplitude of the typical sections less than 0.1mm respectively.The dynamic stiffness of the subgrade ranges from 280MN/m to 350 MN/m and the difference in stiffness of different sections is little.And the accumulated deformation after the circle vibration of 150~200 million times is 0.3～0.4mm.These results indicate that the structural system of "rigid-soft-rigid" in order of depth formed by track,subgrade,pile-board structure and foundation has a favorable long-term dynamic stability.更多还原