大体积混凝土施工过程温度应力场监测及有限元分析

Monitoring of temperature stress fields in large-volume concrete during construction and the finite elements analysis

大体积混凝土由于水泥水化发热导致混凝土在施工及养护过程中出现升温和降温过程,并在混凝土表面和内部产生温度差,受到边界条件的约束在混凝土的表面和内部产生温度应力.大体积混凝土施工中控制温度的本质就是控制温差引起的温度应力.根据某工程的特殊情况,设计了温度测点和温控方案,并对混凝土水化放热公式系数m进行修正,建立了有限元分析模型,分析过程中考虑了混凝土的力学性能随龄期的非线性增长.通过分析,预测了大体积混凝土的温度变化过程及应力分布情况,并与实测数据对比,吻合较好.其成果可为其他类似工程提供参考.

During large-volume concrete pouring and maintenance, temperature would rise and decrease due to hydration, which can cause temperature difference between the inside and surface, and result in stress on account of the boundary constraint . Thus, in large-volume concrete construction, temperature control is crucial to control the temperature stress. According to a specific case, a plan of temperature control and layout of temperature sensor were designed. Then, the coefficient m in concrete hydration exothermic formula was amended. A finite element analysis model was set up, in which the nonlinear increment of concrete＇s mechanical properties with time was taken into account. By finite element analysis, the temperature changing process of large-volume concrete and the distributing features of stress were forecast, which agreed with the measurements. The results brought forward can provide reference for other similar projects.