内外温控条件对超厚防辐射混凝土墙体的温度应力影响研究  

Temperature stress of super thick concrete wall with different external temperature control conditions

作　　者：李潘武[1] 梁肖倩 门凡 金昕 LI Panwu;LIANG Xiaoqian;MEN Fan;JIN Xin(School of Civil Engineering,Chang′an University,Xi′an 710061,China;The Fifth Engineering Company of CCCC Second Harbor Engineering Co.,Ltd.,Wuhan 430000,China)

机构地区：[1]长安大学建筑工程学院,陕西西安710061 [2]中交二航局五分公司,湖北武汉430000

出　　处：《混凝土》2021年第12期147-152,共6页Concrete

基　　金：国家自然科学基金(51579013)。

摘　　要：为了在施工前预测超厚混凝土墙体温度场及应力场从而采取相应的施工措施来预防墙体热裂的问题,以某医用直线加速器的超厚防辐射混凝土结构为工程背景,从内外温控条件入手,使用有限元的方法探讨不同温控条件对超厚混凝土墙体温度应力的影响,以指导实际施工。内部温控应用冷却水管,外部温控以拆模时间与模板种类作以讨论。结果表明,冷却水管可显著降低墙体内部温升,相比无冷管工况,管冷作用下墙体内部温峰出现时间提前至58 h左右,温度峰值降低了18%,约57℃,内外温差控制在17℃以内,表面最大应力减少50%左右。拆模时间关系着降温速率及里表温差,3、5、7、10 d拆模的墙体内部中心平均降温速率分别为3.85、3.14、2.05、1.96℃/d,可适当延长拆模时间,在温峰后3 d左右为宜并辅以保温养护使其降温速率控制在1.5℃/d。模板种类对其温度历程有显著影响,使用木模板的安全系数为1.52,而钢模板仅为1.12,因此对于较厚墙体宜使用保温性能好的模板。Taking the ultra thick radiation proof concrete structure of a medical linear accelerator as the engineering background,starting from the temperature conditions to discuss the influence on the temperature stress of ultra thick concrete wall by using the finite element method,so as to guide the actual construction.The water pipe is used for internal temperature control,and the form removal time and form type are discussed for external temperature control.The results show that the water pipe can significantly reduce the internal temperature rise of the wall.Compared with the non-cooling pipe condition,the internal temperature peak of the wall under pipe cooling is advanced to about 58 h,and the temperature peak is reduced by 18%,about 57℃,the temperature difference between inside and outside is controlled within 17℃,and the maximum stress is reduced by 50%.The average cooling rate of the inner center of the wall in 3,5,7 and10 d is 3.85,3.14,2.05 and 1.96℃/d.The time of formwork removal can be appropriately extended,and it is appropriate to keep the cooling rate at 1.5℃/d about 3 days after the temperature peak.The type of formwork has a significant influence on its temperature history.The safety factor of using wooden formwork is 1.52,while that of steel formwork is only 1.12.Therefore,it is advisable to use templates with good thermal insulation properties for thicker walls.

关 键 词：超厚防辐射混凝土 冷却水管 拆模时间 模板种类 温度应力 

分 类 号：TU528.01[建筑科学—建筑技术科学]