大轴重双线铁路路基结构动力学分析

Dynamic Analysis of Subgrade Structure on Double-track Railway of Heavy Axial Load

随着物资流动要求的提高,重载铁路因其良好的运输能力被社会所青睐,然而用地矛盾限制了线间距的大小,为分析不同线间距对大轴重作用下路基结构的动力响应,借助轨道-路基模型,研究不同轴重、线间距和基床弹性模量下,路基结构的荷载传递规律和动应力分布情况。结果表明:(1)双线铁路线路中心线处基床结构动应力沿深度方向先对数增长,后线性减小;(2)动应力峰值主要与线间距和轴重有关,峰值位置深度主要与线间距有关而与轴重无关;(3)线间距小于4.4 m时,线路中心线处路基本体动应力大于轨道中心线处,对于线间距小于4.4 m的路基结构设计时应考虑线路中心线处动应力值;(4)基床表层弹性模量的衰减作用较小。

With rapid development of economy,the heavy haul railway is favored by the society because of its good transportation ability.However,the line spacing is limited by the contradiction in land utilization.In order to analyze the influence of different line spacing on the dynamic response of the subgrade structure subject to large axle load,load transfer law and dynamic stress distribution of the subgrade structure are studied under different axle loads,line spacing and bed modulus.The conclusions show that:(1)The dynamic stress of the bed structure in the midline of the double line railway line is increased logarithmically first and then decreased linearly in the depth direction.(2)The dynamic stress peak is mainly related to the line spacing and the axle load,and the position of the peak in the depth direction is mainly related to the line spacing and independent of the axle load.When line spacing is increased by 0.2 m each time,the dynamic stress peak is reduced by 4.8 kPa and the position of the peak in the depth direction is increased by 0.15 m.(3)When the line spacing is less than 4.4 m,the dynamic stress of the subgrade body at the midline of the line spacing is greater than that at the midline of the line.When line spacing is less than 4.4 m,the roadbed structure design should take into account the dynamic stress value at the midline of the line spacing.(4)The attenuation of the elastic modulus of the bed surface is smaller.