中文摘要：

为研究地铁列车运行引起的轨道系统及饱和土体动力响应问题,采用解析法建立了饱和土全空间中圆形衬砌隧道和轨道结构耦合分析模型,用一系列符合列车几何尺寸的移动常荷载或移动简谐荷载模拟地铁列车,用无限长圆柱壳模拟衬砌,用Biot饱和多孔介质理论模拟土体,用Euler梁理论模拟钢轨、浮置板并组成两层叠合梁单元,结合轨道与衬砌仰拱处的力和位移连续条件,实现浮置板轨道结构与衬砌及周围饱和土体的耦合。通过算例对比了饱和土体模型和弹性土体模型动力响应的差异,分析了饱和土渗透系数、荷载移动速度和自振频率对轨道结构位移、饱和土体位移及孔压的影响。结果表明：当土体渗透性较差时,饱和土位移响应与相应的弹性土位移响应区别明显,土体模型对轨道结构响应影响较小;随着渗透系数的降低,饱和土体孔压增大;荷载移动速度和自振频率对轨道结构和土体动力响应影响显著。

英文摘要：

To investigate the dynamic response of the track and saturated soil under moving train loading, a coupling model was developed to analyze the rail structure and underground railway tunnel in the saturated soil by using the analytical method. The train load was simulated by a series of moving constant or harmonic load according to the geometry of a real train. The tunnel was simulated as a thin cylindrical shell of infinite length, and the soil was treated as a saturated poroelastic medium using Biot＇s theory. The tracks consisted of two beam units, i.e., an upper Euler-Bernoulli beam to account for the rails and a lower Euler-Bernoulli beam to account for the slab. The tracks and soil medium were coupled by the force and displacement compatibility conditions at the tunnel invert. The different dynamic characteristics of elastic soil medium and saturated soil medium were analyzed. The effects of soil permeability, moving velocity of load, and natural frequency on track responses, rail displacements, and pore pressures of saturated soil were investigated. It is found that the dynamic response of saturated soil medium with a low permeability is different from that of elastic soil medium. But soil model has limited effects on the track responses. The pore pressure increases with decreasing soil permeability. The track responses and pore pressure of the saturated soil are greatly influenced by the velocity and excitation frequency of the moving load.