有轨电车嵌入式轨道路基结构动应力分布规律

Study on dynamic stress distribution law of embedded track subgrade of tram

为分析列车荷载作用下有轨电车嵌入式轨道路基结构动应力分布规律,建立现代有轨电车车辆动力学模型和三维精细化的非线性轨道-路基-地基动力学计算模型,获得在不平顺谱激励下的动态轮轨垂向力,研究列车荷载作用下嵌入式轨道路基结构中动应力沿横向、垂向和纵向的分布规律。研究结果表明:在移动列车荷载作用下,轨道路基结构中的动应力沿横向都呈现驼峰形,且应力极值均出现在钢轨下方;同时在距轨道中心线约1.5 m处,基床表层竖向动应力约等于0,表明路基面宽度取为4m是合理的;当取自重应力的20%作为参考标准时,列车荷载在路基中的影响深度为0.75m;当列车速度为70 km/h时,路基基床表层动应力纵向影响范围约为8.8 m;在对轨道结构进行设计时,建议采用单轴双轮加载,而对路基结构进行设计时,建议使用双轴四轮进行加载。

In order to analyze the dynamic stress distribution law of the embedded track subgrade of tram under the train load, the dynamic model of the modern tram vehicle and a three-dimensional precisely nonlinear track-subgrade-foundation dynamic calculation model were established, and the vertical force of dynamic wheel rail under the irregularity spectrum excitation was obtained. The distribution law of dynamic stress along the transverse, vertical and longitudinal direction of the embedded track subgrade structure under the train load was studied. The results show that under the moving train load, the dynamic stress in the track subgrade exhibits hump shape along the transverse direction and the stress extremum appears below the rail. Secondly, When it is about 1.5 m from the center line of the track, the vertical dynamic stress on the surface of the subgrade is about 0, indicating that the width of the subgrade surface is reasonable for 4 m. Thirdly, When the 20% of self weight stress is taken as the reference standard, the impact depth of the train load in the subgrade is 0.75 m. Finally, When the train speed is 70 km/h, the longitudinal influence range of dynamic stress on the surface of subgrade bed is about 8.8 m.