中文摘要：

研究目的：目前无砟轨道结构在高速铁路中应用广泛，但对其疲劳问题的研究却并不多见。为了探究路基上CRTS Ⅱ型无砟轨道结构体系在恒载、温度和列车往复荷载作用下的疲劳力学性能，本文基于等效静力法实现了CRTSⅡ型板式无砟轨道结构的疲劳力学性能及损伤发展的三维仿真分析，揭示出CRTSⅡ型板式无砟轨道结构体系在运营过程中的经时性能演变规律。研究结论：（1）冬季轨道板大部分区域处于受拉状态，假缝处可能发生开裂损伤；夏季轨道板基本处于受压状态，仅板底假缝附近局部受拉；（2）轨道板、CA砂浆、支承层最大应力随着时间增加而减小，竖向位移差随着时间增加而增大，但都在约20年后趋于稳定；（3）轨道板除假缝（拼缝）位置外基本无严重疲劳损伤，且各条假缝（拼缝）的开裂损伤发展会在5年内趋于稳定，最终各断面的开裂面积比大约稳定在0．7左右；（4）本文可为路基上CRTSⅡ型板式无砟轨道结构体系的设计、维护和维修提供一定的理论依据。

英文摘要：

Research purposes： Ballastless track structures are widely used in high - speed railway nowadays, while little research has been devoted to the analysis of their fatigue behavior. In order to probe into the fatigue properties of CRTS Ⅱ slab ballastless track structure on subgrade under the effect of dead load, temperature and train cycling load, based on the equivalent static analysis method, this paper analyzes the nonlinear three - dimensional finite element in summer, the track slabs are basically compressed, only the area under the slab bottom near the dummy joints is in tension locally. （2）The maximum stress in the track slab, CA mortar and the supporting layer decreases with the increase of time, while the vertical deformation increases with time increasing, and both stress and vertical defomation will be gradually stabilized in about twenty years. （3）In addition to the dummy joints （joint seams）, the track slabs have no serious fatigue damage area, and the cracking damages stabilized in five years, eventually the cracking area ratio （4） This paper can provide the theory basis for the design, structure on subgrade. development of dummy joints （joint seams） would be of each section will be approximately stable at about 0.7. maintenance and repair of the CRTS Ⅱ slab ballastless track