摘要
CRTSⅢ型板式无砟轨道服役过程中,轨道板与自密实混凝土(SCC)层间结合力逐渐退化,诱发离缝病害,影响结构整体性能与行车安全。为探明离缝的主控因素及其形成机制,采用有限元建模方法,构建CRTSⅢ型轨道结构静力分析模型,考虑温度梯度荷载、列车垂向荷载、SCC收缩及其耦合作用,模拟分析层间剪切应力响应与离缝发展机制。研究结果表明:SCC收缩是导致离缝的主控因素,当收缩率为4.5×10^(-4)时,层间最大剪应力达到0.96 MPa,已超过界面抗剪强度0.85 MPa,轨道板边缘率先出现开裂,随后逐步扩展为典型离缝;温度梯度与SCC收缩叠加作用进一步加剧剪应力集中,导致离缝发生的临界收缩率降低至约3.9×10^(-4)。揭示轨道板与SCC层间失效演化的耦合机制,提出可通过降低胶凝材料用量、引入膨胀剂及优化养护条件等方式有效控制SCC收缩率,减缓层间应力积聚,提高结构耐久性与服役安全性。
During the service process of CRTSⅢslab track,the bonding force between the track slab and self-compacting concrete(SCC)layers gradually degrades,inducing the disease of leaving joints,which affects the overall performance of the structure and traveling safety.In order to find out the main controlling factors and the formation mechanism of the separation joints,the finite element modeling method is adopted to construct the static analysis model of CRTS III track structure,and the interlayer shear stress response and the development mechanism of the separation joints are simulated and analyzed by considering the temperature gradient loading,the vertical train loading,the contraction of SCC and its coupling effect.The results show that SCC shrinkage is the main controlling factor leading to the departure seam,and when the shrinkage rate reaches 4.5×10^(-4),the maximum interlayer shear stress reaches 0.96 MPa,which has exceeded the interfacial shear strength of 0.85 MPa,and the edge of the track plate is the first one to show cracking,and then it expands gradually into a typical departure seam;the superimposed effect of temperature gradient and SCC shrinkage further aggravates the shear stress response and the development mechanism of the departure seam.The superposition of temperature gradient and SCC shrinkage further aggravates the shear stress concentration,resulting in the critical shrinkage for the occurrence of the departure joints to be reduced to about 3.9×10^(-4).The study reveals the coupling mechanism between the track slab and SCC interlayer failure evolution,and proposes that the SCC shrinkage can be effectively controlled by reducing the amount of cementitious materials,introducing expansion agents and optimizing the maintenance conditions to slow down the interlayer stress accumulation and improve the structural durability and service safety.
作者
赵欣
尹子熙
汪优
ZHAO Xin;YIN Zixi;WANG You(Hunan Communication Polytechnic,Changsha 410132,China;School of Civil Engineering,Central South University,Changsha 410075,China)
出处
《交通科技与经济》
2026年第2期62-69,共8页
Technology & Economy in Areas of Communications
基金
国家自然科学基金资助项目(51778633)。
