On-site observations show that several damages have occurred in CRTS II slab-type ballastless track system, such as crack and interface debonding between different structural layers, which will trigger the occurrence of some failure modes of CRTS II track slab. As the damages are the prior for specific failure modes, time-dependent reliability of CRTS II track slab should be conducted considering the uncertainties associated with both the failure mode and the damage, which is defined as the conditional time-dependent reliability in this study. To appropriately express the causal relationship among the failure modes and prior damages, a conditional limit state function (LSF) model is proposed with explicit expressions provided. With the aid of the proposed model, conditional time-dependent reliability of CRTS II track slab for two individual failure modes are investigated, which are the steel yielding failure mode under longitudinal cracking, and the vertical instability failure mode under interface debonding. Furthermore, conditional time-dependent system reliability of the track slab has also been analyzed considering four safety failure modes. The advantage of the proposed method is that prior damages have been accounted in establishing the failure criteria and incorporated in the formulation of time-dependent reliability, which provides a general formwork for structural reliability involving the causal relationship among the failure modes and damages.

现场观察表明，CRTS II型板式无砟轨道系统出现了裂缝、不同结构层间界面脱粘等多种损伤，这将引发CRTS II型轨道板的一些失效模式的发生。由于损坏是特定故障模式的先验，CRTS II 轨道板的时间相关可靠性应考虑与故障模式和损坏相关的不确定性，在本研究中定义为条件时间相关可靠性。为了恰当地表达失效模式和先验损伤之间的因果关系，提出了条件极限状态函数（LSF）模型，并提供了显式表达式。在提出的模型的帮助下，研究了CRTS II轨道板在纵向开裂下的钢屈服失效模式和界面脱粘下的垂直失稳失效模式下两种单独失效模式下的条件时间相关可靠性。此外，还考虑了四种安全故障模式，分析了轨道板的条件时间相关系统可靠性。所提出方法的优点是在建立失效准则时考虑了先验损伤，并将其纳入了瞬态可靠性的公式中，这为涉及失效模式和损伤之间因果关系的结构可靠性提供了通用模板。界面剥离下的垂直失稳破坏模式。此外，还考虑了四种安全故障模式，分析了轨道板的条件时间相关系统可靠性。所提出方法的优点是在建立失效准则时考虑了先验损伤，并将其纳入了瞬态可靠性的公式，这为涉及失效模式和损伤之间因果关系的结构可靠性提供了通用模板。界面剥离下的垂直失稳破坏模式。此外，还考虑了四种安全故障模式，分析了轨道板的条件时间相关系统可靠性。所提出方法的优点是在建立失效准则时考虑了先验损伤，并将其纳入了瞬态可靠性的公式，这为涉及失效模式和损伤之间因果关系的结构可靠性提供了通用模板。