承台大体积混凝土水化热分析及温控措施

大体积混凝土会产生大量的水化热导致结构裂缝的出现,对结构的耐久性和承载力产生不利影响,因此需要采取控制措施,减少混凝土内部的梯度温度,控制大体积混凝土结构在施工过程中裂缝的产生。论文采取混凝土内部布置管冷的措施来降低承台大体积混凝土结构在施工过程中产生的水化热,控制混凝土温度裂缝。利用Midas/Civil有限元软件的水化热计算模块进行水阳江特大桥承台大体积混凝土结构的数值模拟,通过无管冷和有管冷的对比分析,确定布置管冷的必要性。研究进水温度、水流量等参数对承台大体积混凝土结构的水化热影响,确定管冷合理的参数取值。分析浇注温度对承台施工过程中温度效应的影响,确定合适的浇筑温度。通过优化分析得到浇筑温度为15℃、进水温度10℃和管冷水流量为2 m~3/h时,其冷却的效果较好并满足规范要求。通过合理的管冷布置和必要的温控措施,能够有效地降低施工中内部温度并且符合工程的实际要求。

The Hydration Heat Analysis of Massive Concrete of Pile Cap and Temperature Control Measures

Mass concrete will produce a large amount of hydration heat, resulting in cracks in the structure, which has an adverse effect on the durability and bearing capacity of the structure. Therefore, measures must be taken to reduce the gradient temperature inside the concrete and prevent cracks in the mass concrete structure of pipe cape in the construction process. In order to reduce the hydration heat generated by the mass concrete structure of the pipe cap and prevent temperature cracks, the measures of concrete interior arrangement and pipe cooling are adopted in this paper. Through the numerical simulation of mass concrete of Shuiyang River Bridge by using hydration heat calculation function of finite element software Midas/Civil, comparative analysis of pipe cooling and no pipe cooling is made to ensure the necessity of arrangement of pipe cooling. The influence of water temperature and water flow rate on the hydration heat of mass concrete structure is analyzed, and the reasonable parameters of pipe cooling are determined. The influence of pouring temperature on hydration heat of pile cap is analyzed, and the suitable pouring temperature is determined. Through the optimization analysis, the cooling effect is better and meets the requirements of the standard when temperature of concrete during construction is 15℃Cand inlet temperature is 10℃ and the pipe cold water flow rate is 2m3/h. With the reasonable design of pipe cooling and necessary temperature control measures, it can play a good cooling effect during the construction process and meet the actual requirements of the engineering.