不均匀沉降对无砟轨道路基动力特性的影响

为探讨不均匀沉降对高速铁路无砟轨道路基动力特性的影响,建立CRTSⅡ型板式无砟轨道-路基系统的三维动力有限元模型,计算并对比分析有病害和无病害条件下路基的竖向动应力、动位移及振动加速度在空间上的分布规律,结果表明路基不均匀沉降导致无砟轨道路基的动力响应幅值及其空间分布规律发生明显的改变,且主要集中在支承层宽度范围、路基面以下0~1.5m深度内。由不均匀沉降引起路基动应力幅值可达100kPa,为无病害路基的3倍以上,动加速度幅值为无病害路基的2倍以上,在列车循环荷载作用下沉降区域将加速扩大,对路基产生非常不利的影响。

The Influence of Uneven Settlement on Dynamic Characteristics of Ballastless Track Subgrade

In order to analyze the influence of uneven settlement on the dynamic characteristics of ballastless track subgrade,a 3-D dynamic finite element model of CRTSⅡ ballastless slab track subgrade is established,and the vertical dynamic stress,the dynamic displacement and the vibration acceleration of subgrade are calculated and analyzed under the conditions with and without defects. The results show that the dynamic response amplitude and spatial distribution of ballastless track subgrade are obviously changed in case of uneven settlement of subgrade,especially in subgrade 0 1.5m深度内。由不均匀沉降引起路基动应力幅值可达100kPa,为无病害路基的3倍以上,动加速度幅值为无病害路基的2倍以上,在列车循环荷载作用下沉降区域将加速扩大,对路基产生非常不利的影响。In order to analyze the influence of uneven settlement on the dynamic characteristics of ballastless track subgrade,a 3-D dynamic finite element model of CRTSⅡ ballastless slab track subgrade is established,and the vertical dynamic stress,the dynamic displacement and the vibration acceleration of subgrade are calculated and analyzed under the conditions with and without defects. The results show that the dynamic response amplitude and spatial distribution of ballastless track subgrade are obviously changed in case of uneven settlement of subgrade,especially in subgrade 0 1. 5 m depth within the scope of bearing Layer. The dynamic stress induced by uneven settlement may reach 100 kpa,which is more than 3 times of the subgrade without defect. Vertical acceleration also increases more than twice of that without defect. Results also show that the area of uneven settlement develops at a higher rate under repeated train load,which may bring great negative impact on subgrade.