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工程实践表明,CRTSⅡ型无砟轨道CA砂浆在施工早期阶段具有较高的开裂风险,为揭示CA砂浆开裂的规律,采用有限元模拟的手段对CRTSⅡ型无砟轨道CA砂浆的早期收缩开裂风险进行了模拟计算。结果表明:CRTSⅡ型无砟轨道CA砂浆两侧边的开裂风险远高于板中部分,侧边部位CA砂浆早期收缩应力随着龄期发展不断增大,第6d后开裂风险因子首次突破临界值1;氢氧化钙类膨胀剂可以有效延迟CA砂浆开裂的时间;CRTSⅡ型无砟轨道侧边CA砂浆28d干燥收缩率小于120×10-6时,在整个观测期内无开裂风险。研究结果可为我国CRTSⅡ型无砟轨道CA砂浆裂缝的预防与控制提供参考。
The engineering practice shows that the CRTS Ⅱ ballastless track CA mortar has a high risk of cracking in the early stage of construction. To reveal the rule of CA mortar cracking, the risk of early shrinkage and cracking of CRTS Ⅱ ballastless track CA mortar is studied by finite element simulation The simulation calculation. The results show that the risk of cracking on both sides of CA mortar of CRTS Ⅱ ballastless track is much higher than that of the middle part of the mortar. The early shrinkage stress of CA mortar on the side edge increases with the development of age. After 6 days, the cracking risk factor of CR mortar breaks through the critical value 1; Calcium hydroxide expansive agent can effectively delay the cracking time of CA mortar; when the dry shrinkage rate of CA mortar on the side of CRTS Ⅱ type ballastless track 28d is less than 120 × 10-6, there is no risk of cracking during the whole observation period. The results can provide reference for the prevention and control of cracks in CA mortar of CRTS Ⅱ ballastless track in China.