摘要
[目的]目前,对于装配叠合整体式地下车站防水关键技术研究较少,探究装配叠合整体式地下车站预应力叠合板开裂风险,有助于提升浇筑质量,有助于装配叠合整体式地下车站技术推广应用。[方法]主要采用“水化-温度-湿度-约束”多耦合机制抗裂评估方法,对车站预应力叠合板的预制构件及后浇混凝土开裂风险进行评估。介绍了混凝土构件开裂风险评估方法和计算模型,并采用该方法进行了混凝土预制构件和后浇混凝土开裂风险评估。[结果及结论](1)预制顶板构件生产过程中,应加强表面早期保湿养护,蒸气养护时应控制降温速率不大于2.2℃/h。(2)后浇筑顶板采用基准混凝土施工,一次性浇筑长度由18 m增大到24 m时,靠近侧墙附近中心最大开裂风险从0.98增大到1.21。顶板变截面较厚的地方温升较大,应力较大;而较薄的地方温升较小,应力较小,分布呈齿状。(3)后浇筑顶板采用抗裂混凝土施工,一次性浇筑18~24 m时,最大开裂风险均降至0.7以下。建议整体装配式车站现浇顶板采用抗裂混凝土施工,可降低开裂风险。
[Objective]Current research on the key water⁃proofing technologies for prefabricated composite underground stations is limited.Investigating the cracking risk of prestressed composite slabs in such stations can enhance casting quality and promote the application of prefabricated composite underground station technologies.[Method]The anti⁃cracking assessment method with′hydration⁃temperature⁃humidity⁃constraint′multi⁃coupling mechanism is primarily adopted to assess the cracking risk of both prefabricated components and post⁃poured concrete in station prestressed composite slabs.[Result&Conclusion]1)During the production of prefabricated roof slab compo⁃nents,it is crucial to enhance early surface moisture curing,and the cooling rate during steam curing should be controlled to not exceed 2.2℃/h.2)For post⁃poured roof slabs using standard concrete,when the length of a single pour is increased from 18 m to 24 m,the maximum cracking risk near the center close to the sidewalls rises from 0.98 to 1.21.Thicker sections of the roof slab experience greater temperature rises and stress,while thinner sections have lower temperature rises and stress,resulting in a serrated distribution.3)When using anti⁃crack concrete for post⁃poured roof slabs with pour lengths between 18 m and 24 m,the maximum cracking risk is reduced to be⁃low 0.7.It is recommended that cast⁃in⁃place roof slabs of prefabricated composite stations use anti⁃crack concrete to min⁃imize cracking risk.
作者
刘毅
莫振泽
胡正波
彭宇一
卫佳莺
张祖雪
LIU Yi;MO Zhengze;HU Zhengbo;PENG Yuyi;WEI Jiaying;ZHANG Zuxue(Wuxi Metro Construction Co.,Ltd.,214023,Wuxi,Chi⁃na;Wuxi Metro Group Co.,Ltd.,214023,Wuxi,China;China Railway Fourth Survey and Design Institute Group Co.,Ltd.,430063,Wuhan,China)
出处
《城市轨道交通研究》
北大核心
2024年第S2期83-88,93,共7页
Urban Mass Transit
关键词
地铁车站
装配叠合整体式
预制板
后浇混凝土
开裂风险
metro station
prefabricated composite
precast slab
post⁃poured concrete
cracking risk
作者简介
通信作者:刘毅,高级工程师,746151309@qq.com
