基于高周疲劳损伤本构模型的无砟轨道自密实混凝土的性能演化规律

Performance evolution of self-compacting concrete for ballastless track based on high-cycle fatigue damage constitutive model

CRTSⅢ型板式无砟轨道自密实混凝土(SCC)填充层在列车荷载和复杂环境反复作用下易产生高周疲劳损伤。本文基于损伤-有限元全耦合技术,建立了CRTSⅢ型板式无砟轨道自密实混凝土疲劳损伤分析方法,探讨了列车荷载、初始劣化、板端脱粘等因素对填充层性能演化的影响。计算结果表明:全耦合方法可以揭示疲劳损伤与结构应力场的相互影响机制,弥补了传统解耦法结构应力不随损伤累积而变的局限性;列车荷载变化下,填充层在服役期内的损伤累积近似服从Miner线性准则,在初始应力水平达到0.33附近时,填充层疲劳损伤随荷载作用次数的增加出现非线性累积现象,采用全耦合法更能体现出结构的时变性;相较于自密实混凝土填充层初始劣化和列车荷载变化,板端脱粘对损伤累积的影响更为突出。

The self-compacting concrete(SCC)filling layer of CRTSⅢballastless track is prone to high-cycle fatigue damage under repeated train loads and complex environments.Based on the technology that fully couples damage and finite elements,a fatigue damage analytical method of SCC for the CRTS III ballastless track was established,which discussed how train load change,initial deterioration,and slab end debonding would affect the performance evolution of the filling layer.It is found that the fully-coupled method can reveal the interaction between fatigue damage and the structure’s stress field.As the train load changes,the damage of the filling layer during the service period accumulates pretty much following Miner’s rule in the first place.However,when the initial stress level reaches around 0.33,the fatigue damage of the filling layer presents nonlinear accumulation with the increase of loading times.Therefore,the fully-coupled method at this time can better reflect the time-varying features of the structure.Compared with initial deterioration of the SCC filling layer and the change of train loads,slab end debonding has a more prominent effect on damage accumulation.