高速铁路桥路过渡段动应力测试与分析

研究目的:高速列车的平稳、安全运营,需要路基结构物提供沉降小、刚度大、动力特性稳定的轨下支撑系统。在武广高速铁路设计中,为实现桥梁与路基的刚度和沉降平顺过渡,设置了桥路过渡段。在过渡段中预埋设动测元件,研究CRH2动车组高速通过过渡段的动应力的空间分布特性。研究结论:桥路过渡段路基基床表层动应力的最大值位于过渡段正梯形底部折角处,均值约12.73 kPa;桥路过渡段路基基床表层采用级配碎石加强后,动应力在垂向衰减较快,至基床底层底面时,衰减率达90%;列车速度由200 km/h增加到250 km/h时,路基基床表面动应力增加约20%;车速由250 km/h增加到350 km/h时,过渡段路基基床表面的动应力增加约10%。

Test and Analysis of Dynamic Stress of Bridge-subgrade Transition Section of High-speed Railway

Research purposes: The smooth and safety operation of high-speed train need the subgrade to provide the sub-rail supporting system with the small settlement,high stiffness and stable dynamic characteristics.For the Wuhan-Guangzhou high-speed railway,the bridge-subgrade transition section was designed to realize the smooth transition of stiffness and settlement between the bridge and subgrade.The test cells were placed in test transition section during the construction to test the spatial distribution characteristics of the dynamic stress when the CRH2 EMU run in the transition section. Research conclusions:The maximum dynamic stress of bridge-subgrade transition section appeared in the turn corner of the trapezoidal bottom of the transition section with the average value of 12.73 kPa.After the surface of the foundation bed of the transition section was reinforced by the graded broken stone,the dynamic stress of transition section in the vertical reduced quickly and the attenuation rate was up to 90% on the bottom of the subgrade bed.The dynamic stress of the bed surface in the transition section increased by about 20% when the train speed increased from 200 km/h to 250 km/h,and the dynamic stress of the bed surface increased by about 10% when the train speed increased from 250 km/h to 350 km/h.