大体积混凝土承台温度应变观测与分析

Temperature Strain Observation and Analysis of Large Volume Concrete Bearing Platform

随着我国大型桥梁工程的建设,大体积混凝土施工技术逐步应用与成熟。为了探究特大桥承台施工过程中由于水泥水化热反应引起的结构变形特征,对现场温度与应变监测数据进行交互分析,研究结果表明:大体积混凝土结构内外温度变化存在同步性和差异性,施工早期结构呈指数形式升温;混凝土水化热引起的温度变化是结构产生微应变的主导原因,结构表面产生显著拉应变,是引发混凝土开裂的主要因素,降低施工过程中混凝土内外温差是避免结构表面开裂,控制结构稳定性保证耐久性的有效途径。

With the construction of large bridges in China,the construction technology of large volume concrete is gradually applied and matured.In order to explore the structural deformation characteristics caused by the thermal reaction of cement hydration during the construction of the bearing platform of a large bridge,the field temperature and strain monitoring data were analyzed interactively,the research results show that:the internal and external temperature changes of the mass concrete structure are synchronous and different,and the early construction structure is in the form of exponential temperature rise.The temperature change caused by the hydration heat of concrete is the leading cause of micro-strain of the structure,and the significant tensile strain on the surface of the structure is the main factor causing concrete cracking.