高速铁路无砟轨道−路基动应力特性分析

Dynamic stress characteristics of ballastless track-subgrade coupled system of high-speed train railway

为研究无砟轨道−路基在高速列车运行过程中的振动响应,采用有限元方法在时域中建立全尺寸3D路基模型,分析路基各层动应力水平及其沿线路竖向、横向和纵向的变化幅度,并将武广、遂渝铁路实测数据与模型结果进行对比。研究结果表明:在竖直方向上,有限元计算的路基各处动应力均略高于线路实测数据,地基顶面衰减值较为接近,在z=0.4、2.7、4.7 m处衰减值分别为95%、47%、30%,而模型试验最终衰减值较高。路基动应力在基床表层范围内沿线路横向呈“马鞍形”分布,线路中心与支撑层边缘差值较大,随着路基深度的增加,分布特征逐渐转变为中间高两边低,向线路两侧衰减且差值较小。路基动应力沿纵向呈“高斯”分布特征,路基各层竖向动应力幅值沿线路y向衰减一致,轨道板边缘处荷载衰减至轨道板中心的13%~16%。

In order to study the vibration response of the ballastless track and subgrade to high-speed train,the finite element method was used to established a full-scale 3D subgrade model in the time domain.The dynamic stress level of each layer of the subgrade,and the amplitude of variation at the direction of vertical and horizontal were analyzed.The modeling results were compared with the measured data of the Wu-guang and Sui-yu railway lines.The results show that,in the vertical direction,the dynamic stress of the subgrade of modeling is slightly higher than that of the measured data,and the attenuation value of the top surface of the foundation is almost identical,the value at the position of z=0.4 m,2.7 m and 4.7 m is 95%,47%and 30%,respectively.And the final attenuation value of the model test is relatively high.The dynamic stress surface of the subgrade is distributed in a saddle-shape along the line transversely.The difference between the center and the edge of the support layer is obvious.The distribution characteristic gradually change to the high in the middle and low on both sides with the increase of depth.And the value attenuated to both sides of the line.The dynamic stress of the subgrade is characterized by the obvious of the Gauss along the longitudinal direction,and the amplitude of the vertical dynamic stress of each layer of the subgrade is basically attenuating along the y direction of the line.The load at the edge of the track slab is reduced to the 13%~16%of that at the center of the track.