高速铁路板式无砟轨道-路基结构动力特性研究

Study on the Dynamic Properties of Slab Ballastless Track and Subgrade Structure on High-speed Railway

针对列车走行的实际情况,将板式无砟轨道-路基作为参振子结构纳入车辆计算模型,建立包含车辆、钢轨、板式轨道和路基为一体的二系垂向耦合动力分析模型,分析列车速度对车辆运行品质、系统动位移以及动应力的影响。结果表明:车体加速度、动轮载和轮重减载率均随车速的提高而增大,呈线性分布,当列车高速通过无砟轨道-路基结构时,列车运行的安全性和舒适度指标都能满足要求;系统动位移受速度影响较小;轨道板易发生疲劳破坏,需采用双层、双向配筋;路基面动应力随速度的提高而增大,但数值比有砟轨道的小;路基动应力沿路基深度方向衰减较慢,在基床表面下3 m处,动应力只有基面的25%左右;无砟轨道的基床加速度远小于有砟轨道的加速度值,表明无砟轨道结构可以有效地改善列车荷载对路基基床的振动作用。

In view of the actual train running conditions,the slab ballastless track-subgrade being regarded as part of the vibration structure of the vehicle mode1,the dynamic model of the secondary suspension vertical coupled system including the vehicle,rail,slab track and subgrade is established.The influence of the train speed on the vehicle running quality and the dynamic displacements and dynamic stresses of the system is analyzed.The results show as follows：The vertical vehicle acceleration,dynamic wheel load and offload factors increase with the train speed and they are all distributed linearly;the indexes of safety and comfort of train running can meet relevant requirements when a high-speed train passes through the ballastless track-subgrade structure;dynamic system displacements are influenced by train speeds to a small extent;the slab track is liable to fatigue failures,so it must be reinforced in double deck in both directions;the dynamic stress of the subgrade surface increases with speed raising,but its value is smaller than that with the ballasted track;the dynamic stress of the subgrade attenuates slowly along the depth of the subgrade,the dynamic stress 3 m deep below the subgrade bed surface is about 25 percent of that of the subgrade bed surface;the subgrade bed acceleration in the ballastless track system is far less than that in the ballasted track system,which indicates vibration of the subgrade bed caused by train loading can be improved effectively with the ballastless track structure.The research results agree well with the existing document ation,the reliability of the model is soverified.