中文摘要：

建立了重载货车-有砟轨道-路基系统耦合动力学模型．分析计算了在轨道随机不平顺激励下30t轴重重载铁路轨道-路基系统动位移的分布规律．计算结果表明：①轨道-路基系统各结构层动位移状态较为复杂，在重载货车通过的过程中，所受荷载也处于循环往复的加载和卸载状态．②在有砟轨道-路基系统的动位移的3个位移分量中，竖向动位移的幅值较大，横向动位移以及纵向动位移的幅值均不超过竖向动位移幅值的6％；而沿横向，动位移的分布较为缓和，其最大波动幅值不超过0．2mm，可近似看做均匀分布．③轨道-路基系统动位移沿竖向的变化，大体分为3个阶段：在钢轨到轨枕之间，出现明显突变；在轨枕层区域的衰减幅度较小；在道床层至基床表层及下部结构，竖向动位移表现为沿深度方向不断衰减，并且衰减速率随着深度的增加也在不断减小．

英文摘要：

A dynamical interaction model of the ballasted track, subgrade and heavy haul train system was developed. The distribution of displacement of the heavy haul railway ballasted Track-subgrade system under 30 t axle freight vehicle running are solved using the combination of the new rapid explicit integration method and the Newmark integration method. The results show that the dynamical displacement state of each structure layer of the track-subgrade system is complex, and the load is in the cyclic loading and unloading during heavy haul vehicle passing. The amplitude of vertical dynamic displacement is the largest in three components of the displacement of the track-subgrade system, while the amplitude of the lateral displacement and longitudinal displacement are less than 6 % of the amplitude of the vertical dynamic displacement. The dynamic displacement distribution in lateral direction, of which the amplitude fluctuation is less than 0.2 mm, is relatively moderate and could be approximated as uniform distribution. The changes of the dynamic displacement of the track-subgrade system in vertical direction could be divided into three phases： for the first part between the rail and the sleeper, the amplitude of dynamic displacement attenuates distinctly; for the second part, the amplitude of dynamic displacement attenuates gently in the sleeper region; and for the third part under the ballast bed, the amplitude of dynamic displacement attenuates continuously along the vertical direction, and the rate of attenuation is continuously decreasing with the increase of the depth.