大体积防辐射混凝土冬季施工温差控制

Temperature Difference Control of Radiation-shielding Mass Concrete Construction in Winter

以中国医学科学院肿瘤医院分院(廊坊院区)直线加速器室混凝土冬季施工为工程背景,对大体积防辐射混凝土冬季施工温差控制进行了研究。通过有限元数值模拟了混凝土温度场的分布规律,提出不同部位混凝土施工应采用不同的温差控制措施,并通过现场监测验证了温差控制措施的有效性。研究结果表明:环境温度和混凝土入模温度仅影响不同构件中混凝土的温度峰值和温升值,不会改变混凝土温度场的分布规律,即墙体、顶板和底板中混凝土的高、低温分布区域是一致的;混凝土浇筑时长影响入模温度,从而造成数值模拟结果与现场监测结果存在一定的差异,应对数值模拟结果进行修正。该研究采取的墙体双层模板、顶板蓄水养护、底板覆盖保温棉被的温差控制措施有效且稳定。

Taking the linac chambers of the cancer hospital branch of Chinese Academy of Medical Sciences(Langfang Campus)as an example,a study was conducted on the temperature difference control of radiation-shielding mass concrete constructed in winter.The distribution pattern of the concrete temperature field was finite element numerical simulation.It was proposed that different temperature difference control measures should be adopted in different parts of concrete construction.The effectiveness of the temperature difference control measures was verified by on-site monitoring.The research results show that the environment temperature and concrete molding temperature only affects the peak temperature and temperature rise of concrete in different components,and don't change the temperature distribution law of concrete temperature field.That is,the high and low temperature distribution areas of concrete of walls,top plates,and bottom plates are consistent;The duration of concrete pouring affects the molding temperature,resulting in a certain difference between the numerical simulation results and the on-site monitoring results.The numerical simulation results should be improved.The temperature difference control measures adopted in this study include double-layer formwork for the wall,water storage and maintenance on the top plate,and thermal insulation quilt covering the bottom plate,which are effective and stable.