摘要
渠江风洞子航运工程泄洪冲沙闸底板需浇筑超4万m3混凝土,因此减小大体积混凝土结构开裂风险成为该工程品控的重要一环。通过前期调研和现场试验得到混凝土材料的热工参数、物理性能及边界条件,使用有限元软件计算泄洪闸冲沙底板在采用不同控裂措施下的温度场,分析结构内部应力情况,并引入抗裂安全系数指标,评价底板结构在不同工况下的开裂风险。结果表明:在泄洪冲沙闸底板合理位置进行分缝浇筑能显著减小底板结构的开裂风险,使各结构层抗裂安全系数均高于临界值;采用低热水泥施工也能对底板结构的开裂风险产生较大的增益效果,各结构层自、外约束抗裂安全系数最大分别可提升65.2%、25.9%。为降低底板大体积混凝土结构整体开裂风险,提出在施工技术条件允许的情况下应合理采用分缝措施;在经济条件允许的前提下,采用低热水泥也应作为控裂措施之一。
More than 40000 m3 concrete needs to be poured at the bottom slab of the floodgate of the Fengdongzi navigation project of the Qujiang River,so reducing the cracking risk of the mass concrete structure becomes an important part of the quality control of the project.The thermal parameters,physical properties and boundary conditions of concrete materials are obtained through preliminary investigation and field tests.The finite element software is used to calculate the temperature field of the floodgate under different crack control measures,analyze the internal stress of the structure,and introduce the safety factor of crack resistance index to evaluate the cracking risk of the floodgate under different working conditions.The results show that setting construction joints at the reasonable position of the bottom slab of the floodgate can significantly reduce the cracking risk of the bottom slab structure,and the safety factor of crack resistance of each structural layer is higher than the critical value.Using low-heat cement can also have a great gain effect on the cracking risk of the bottom slab structure,the maximum safety factor of self restraint and external restraint crack resistance of each structural layer can be increased by 65.2%and 25.9%respectively.In order to reduce the whole cracking risk of the mass concrete structure of the bottom slab,it is proposed that construction joints should be reasonably set if the construction technical conditions permit.If economic conditions permit,low-heat cement is also used as one of the crack control measures for pouring concrete.
作者
张启航
曹恒
彭茂军
邓春林
黎鹏平
于方
ZHANG Qihang;CAO Heng;PENG Maojun;DENG Chunlin;LI Pengping;YU Fang(CCCC Fourth Harbor Engineering Research Institute Co.,Ltd.,Guangzhou 510230,China;The Fourth Engineering Company of CCCC Fourth Harbor Engineering Co.,Ltd.,Chengdu 610000,China)
出处
《建筑结构》
北大核心
2023年第S01期2280-2286,共7页
Building Structure
关键词
大体积混凝土结构
有限元
低热水泥
浇筑长度
抗裂安全系数
mass concrete structure
finite element
low heat cement
pouring length
safety factor of crack resistance
