采用精细化和多尺度建模技术，建立了设计速度为350 km/h的双线高速铁路轨道-路基-地基非线性耦合系统的真三维动力分析模型，将地基土和路基填筑材料的非线性纳入分析模型中，采用三维黏弹性静-动力统一人工边界技术对地基无限域进行模拟，采用动接触算法模拟底座板底面和基床表层表面之间的相互作用，考虑移动荷载作用前路基-地基中客观的静应力状态对后续动力计算的影响，依托大规模并行计算技术和单元生死技术，模拟了地基的初始应力场生成、路基结构和轨道系统的施工过程，在此基础上模拟了与8辆编组的某型动车组轮对空间位置相对应的、作用于钢轨顶部的压力荷载的移动过程。基于分析结果，归纳了移动荷载作用下高速铁路轨道-路基-地基系统中振动加速度频谱的衰减特性。

A coupled nonlinearly three-dimensional track-embankment-foundation numerical model for double line high-speed railway with a design speed of 350 km/h was established based on precisely modeling and multi-scale method. The material nonlinearities of foundation soil and embankment backfill were incorporated in the model. The infinite foundation was simulated using three-dimensional viscoelastic static-dynamic unified artificial boundaries. The dynamic reinforced concrete base-upper layer of formation interaction was modeled using dynamic algorithm. Considering the influence of static stress state prior to activation of moving loads on subsequent dynamic analysis, the generation of initial stress state of foundation and construction of embankment and track system were modeled based on multi-scale computation and element birth and death method; and then the movement of loads was simulated. The loads corresponding to the wheel set locations of CRH EMU train with 8 carriages were applied to the surface of the top layer element of rail. The attenuations of vibration acceleration spectra due to moving loads in track-embankment- foundation were summarized based on the calculated results.