高速铁路无砟轨道基础结构垂向位移分布特性分析

建立高速铁路无砟轨道-路基结构动力有限元模型,系统分析高速列车荷载作用下轨道和路基垂向位移在时间和空间上的分布规律,比较轨道不平顺和断面位置对位移分布的影响规律。数值分析结果表明,轨道不平顺和横断面位置对轨道和路基垂向位移分布的影响可以忽略不计;高速列车荷载作用下钢轨和轨道板垂向位移的最大值分别为0.79mm和0.238mm,结果都在京津铁路现场试验实测数据的范围之内;轨道板和底座的垂向位移沿横向衰减非常缓慢,仅分别降低了3.6%和6.5%,沿深度基本没有变化;路基各层面垂向位移在轨道宽度范围内沿横向仅衰减10%左右,轨道宽度范围外位移按指数函数快速衰减,在距离线路中心线3m和4m附近,基床表层和基床底层的垂向位移已衰减一半以上,路基位移沿深度线性衰减,在距钢轨底面4m附近,垂向位移衰减50%左右,到基床底面处位移衰减70%以上。

Vertical displacement distributions of ballastless track infrastructure of high-speed railways

A 3D dynamic finite element model of track-subgrade system was established for a typical ballastless slab track railway structure to analyze the vertical displacement distributions of the railway track and subgrade under high-speed train loads.Influences of track irregularity and cross section location on the displacement distribution were investigated.Numerical results indicate that track irregularity and cross section position have little influence on the displacement distribution of the track and the subgrade.The maximum vertical displacements of the rail and the track are 0.79mm and 0.238mm,respectively,which agree well with field experiments data in the Beijing-Tianjin intercity railway line.The vertical displacement of the track attenuates very slowly in the lateral direction from the track center.The displacements of the slab and the concrete foundation decrease only 3.6% and 6.5% in the lateral direction,respectively,and there is almost no attenuation in the vertical direction.The displacement of the subgrade attenuates only 10% along the lateral direction in the range of track width.Outside this range,the subgrade displacement decreases rapidly as exponentially with the increase of the distance away from the track central line.The displacements of ballast surface and ballast bottom attenuate over 50% at the points away 3m and 4m from the track central line,respectively.The subgrade displacement decreases linearly along the depth.It attenuates about 50% at the point away 4m from the rail bottom,and the displacement of the ballast bottom is only 30% of the subgrade surface displacement.