摘要
由于大体积混凝土侧墙降温过程快速收缩,且受先浇筑混凝土的约束,易产生贯通性裂缝的问题。针对该问题,以深圳地铁大运站为背景,分析车站侧墙在施工中温度场与应力场的分布规律,确定易开裂部位;提出预埋冷却管的控制措施,分析不同冷却管参数对温度应力的影响规律,确定合适的布置参数,并通过现场实测进行验证。结果表明:无冷却管时,侧墙上表面应力较大,且大于混凝土即时抗拉强度;采用冷却管能有效降低表面温度应力,其中冷却管材质、进水温度和管间距对温度应力的影响显著,管径与流量的影响较小;相较于无冷却管时混凝土的表面温度应力,钢质与PVC冷却管分别能降低35.0%和28.4%;合理布置冷却管后,内表温差与温度应力均满足标准,有效控制了侧墙大体积混凝土温度裂缝的产生。
Due to the rapid cooling shrinkage of the mass concrete side walls and the constraint of the concrete cast earlier,the problem of transverse cracks is prone to occur.In response to this issue,with the background of Shenzhen Metro Dayun Station,the distribution laws of temperature and stress fields in the station's side walls during construction were analyzed to identify the susceptible cracking locations.Control measures of embedding cooling pipes were proposed,analyzing the influence of different cooling pipe parameters on temperature stress,determining appropriate layout parameters,and verifying them through on-site measurements.The result show that without cooling pipes,the surface stress of the side walls is higher and exceeds the instantaneous tensile strength of concrete.Using cooling pipes can effectively reduce surface temperature stress,with the material,inlet water temperature,and spacing of the cooling pipes significantly affecting temperature stress,while the effects of pipe diameter and flow rate are relatively minor.Compared to the surface temperature stress of concrete without cooling pipes,steel and PVC cooling pipes can reduce it by 35.0%and 28.4%respectively.After reasonable arrangement of cooling pipes,both the inner surface temperature difference and temperature stress meet the standards,effectively controlling the generation of temperature cracks in the mass concrete of the side walls.
作者
杨飞
刘犇
张欣
丁岳森
王建佳
康瑞强
YANG Fei;LIU Ben;ZHANG Xin;DING Yuesen;WANG Jianjia;KANG Ruiqiang(China Railway Fifth Bureau Group South China Engineering Co.,Ltd.,Dongguan 523000,Guangdong,China;School of Civil Engineering,Central South University,Changsha 410075,Hunan,China)
出处
《水利水电技术(中英文)》
北大核心
2024年第S2期724-732,共9页
Water Resources and Hydropower Engineering
关键词
车站侧墙
大体积混凝土
冷却管参数
温度应力
station sidewall
mass concrete
cooling pipe parameters
temperature stress
