车站底板大体积混凝土浇筑的温度效应

Temperature effect of mass concrete pouring on station floor

为了对地铁车站底板大体积混凝土浇筑后的温度效应进行研究,依托成都地铁19号线华兴街车站的大体积混凝土底板浇筑工程,采用现场监测与数值计算分析方法,探讨水化反应引起的混凝土干缩和自收缩特性.利用有限元分析软件,采用分层分段的方式施加温度场,模拟混凝土底板应变的变化特征,分析引起大体积混凝土底板变形的主要因素,并结合地铁车站施工特点和工期,提出合理化的控制措施.研究结果表明:大体积混凝土底板各层温度和应变存在较大的差异;龄期为0~3.0 d时,底板变形的主要影响因素为混凝土剧烈水化反应后的干缩和自收缩;龄期为4.0~10.0 d时,主要影响因素为混凝土内部散热不均产生的温度效应和温差效应.

To investigate the temperature effect of the mass concrete on the subway station bottom slab after pouring, based on the mass concrete bottom slab pouring project of Huaxing Street Station of Chengdu Metro Line 19, the dry shrinkage and self-shrinkage characteristics of concrete caused by hydration heat reaction were discussed by field monitoring and numerical analysis method. Using the finite element analysis software, the temperature field was applied to simulate the strain variation characteristics of the concrete bottom plate by stratification and subsection. The main factors on the deformation of mass concrete bottom plate were analyzed, and the reasonable control measures were proposed based on the construction characteristics and construction period of the subway station. The results show that there are great differences in temperature and strain of each layer of mass concrete floor. When the pouring days are 0-3.0 d, the main influencing factors on floor deformation are the dry shrinkage and the self-shrinkage of concrete after intense hydration reaction. When the pouring days are 4.0-10.0 d, the main influencing factors are the temperature and the temperature difference effect caused by the uneven heat dissipation of concrete.