基于管冷系统的大体积混凝土水化热时变温度效应  

Time varying temperature effect of hydration heat of mass concrete based on pipe cooling system

作　　者：侯炜[1,2] 宋一凡[1,2] 马超 HOU Wei;SONG Yi-fan;MA Chao(Key Laboratory of Transport Industry of Bridge Detection Reinforcement Technology,Chang'an University,Xi'an 710064,Shaanxi,China;School of Highway,Chang'an University,Xi'an 710064,Shaanxi,China)

机构地区：[1]长安大学旧桥检测与加固技术交通运输行业重点实验室,陕西西安710064 [2]长安大学公路学院,陕西西安710064

出　　处：《长安大学学报（自然科学版）》2021年第4期65-77,共13页Journal of Chang’an University(Natural Science Edition)

基　　金：国家自然科学基金项目(51878057);陕西省自然科学基础研究计划项目(2021JM-174);中央高校基本科研业务费专项资金项目(300102210105)。

摘　　要：为研究大体积混凝土水化反应过程中的时变温度效应,以黄土地区亚洲第二高墩天宁沟特大桥为研究对象,建立主墩承台有限元模型,分析大体积混凝土承台水化热时变温度效应;通过数值模拟优化现场管冷系统,并布置温度传感器实测大体积混凝土承台内表时变温度场,验证所建立模型的准确性;在此基础上,分析混凝土入模温度、导热系数和表面对流系数对大体积混凝土承台内部绝热温升、表面温升和内表温差的影响。研究结果表明:有限元计算所得大体积混凝土承台内部绝热温升与实测结果基本吻合,但其出现时间较实测值滞后约60 h;受环境温度和保温措施的影响,大体积混凝土承台表面实测温度波动较大,内表温差也呈波动状态;混凝土入模温度与大体积混凝土承台内表最高温和内表温差线性相关,较低的混凝土入模温度能迅速降低混凝土最大绝热温升,绝热温升越大,混凝土入模温度对其内表最大温升和内表温差的影响越大;大体积混凝土承台最大绝热温升出现时间与混凝土导热系数对数相关,混凝土导热系数越大,其最大绝热温升越大;绝热温升受混凝土表面对流系数的影响较小,但混凝土结构进入降温阶段后,其表面对流系数越大,内部温度降低速率越快;混凝土表面温升受其表面对流系数的影响较大,混凝土表面对流系数越小,其表面最大温升越大,结构进入降温阶段后,混凝土表面温度降低速率越快。In order to study the time-varying temperature effect in the hydration process of mass concrete,Tianninggou Bridge in Loess Area,which is the second highest pier in Asia was taken as the research object,the finite element model of main pier bearing platform was established.The hydration heat and temperature effects of mass concrete bearing platform were analyzed.The accuracy of model was verified by measuring the temperature field on the inner and surface of mass concrete bearing platform with temperature sensors arranged on site.On this basis,the influences of concrete pouring temperature,thermal conductivity coefficient and surface convection coefficient on the internal adiabatic temperature rise,surface temperature rise and temperature difference between the inner and surface of mass concrete bearing platform were analyzed.The results show that the adiabatic temperature rise of mass concrete bearing platform calculated by the finite element method is consistent with the measured results,but its occurrence time is about 60 h later than the measured value.Due to the influence of environmental temperature and thermal insulation measures,the measured temperature on the surface of mass concrete bearing platform fluctuates greatly,and the temperature difference between the inner and surface of mass concrete bearing platform fluctuates.The concrete pouring temperature is linearly correlated with the maximum temperatures of inner and surface of mass concrete bearing platform,and temperature difference between the inner and surface of mass concrete bearing platform.The low concrete pouring temperature can quickly reduce the maximum adiabatic temperature rise in the mass concrete bearing platform.The greater the inner adiabatic temperature rise of concrete is,the greater the influences of concrete pouring temperature on the maximum temperature rises of inner and surface of concrete,and the temperature difference between the inner and surface of concrete.The occurrence time of the maximum adiabatic temperature rise insid

关 键 词：桥梁工程 大体积混凝土 水化热 温度效应 绝热温升 内表温差 

分 类 号：U445.57[建筑科学—桥梁与隧道工程]