水化热引起的大体积混凝土墙应力与开裂分析

Analysis of hydration heat-induced stresses and cracks in massive concrete walls

应用基于Arrhenius理论的混凝土绝热温升和徐变模型 ,考虑温度对早期混凝土水化热化学反应速率和徐变特性的影响 ,研究了大体积混凝土墙的温度应力和温度开裂问题 ,并提出了求解非线性微分方程的半解析法 .研究中采用Bazant教授提出的裂缝带模型计算温度裂缝 ,采用半解析迭代法逐步加载计算温度、应力和裂缝的产生与扩展 .研究结果表明 ,浇筑温度极大地影响材料的热学力学性质和结构的温升、温度应力和开裂 .研究还揭示了不同养护条件对温度。

By use of the Arrhenius theory based concrete adiabatic temperature rise and creep models, and in consideration of the influences of temperature on hydration heat chemical reaction rate and creep property of concrete in the early age, an analysis is performed of the temperature induced stresses and cracks in massive concrete walls. In the analysis, a semi analytical method is proposed to solve nonlinear differential equations, and Bazant's crack band model is used to calculate the temperature induced cracks. The cracks are divided into equal strips, and the semi analytical iteration method with stepwise loading is developed to calculate the relationships between temperature, stresses, and propagation of cracks. The results show that the cast temperature of concrete is of great effects on the thermodynamic property of materials and on temperature rise and temperature induced stresses and cracking of concrete structures. Besides, the influences of different curing conditions on temperature, stresses, and cracking of concrete are also revealed.