摘要
该文依托广西龙门大桥锚碇填芯超大体积海工混凝土结构(58606 m^(3)),对连续浇筑期混凝土的温度梯度演化规律开展在线监测和真实温度场、应力分析,对混凝土结构的温控防裂具有重要意义。该文首先研发了温度梯度在线监测系统,可实现在线实时采集混凝土温度梯度变化数据,反馈实际温度与允许阈值间偏差功能,可为及时预警和精准温控提供依据;其次通过构建真实温度场并计算温度应力,揭示了在连续浇筑条件下超大混凝土结构的真实温度梯度演化规律,提出了温度开裂控制梯度指标。工程实践表明:温度梯度在线监测系统能保证现场精准动态温控方案较好地实施,从而有效控制开裂风险。研究成果可供同类工程温控防裂设计和施工参考。
[Objective]Bridge anchorage core concrete,a typical mass-filling marine concrete structure,faces challenges in temperature change control and crack prevention due to its special shape,continuous casting,and complicated boundary.[Methods]Based on the mass-filling concrete of the Guangxi Longmen Bridge anchorage basement(58606 m^(3)),this paper conducts an online monitoring and analysis of the real thermal field and stress distribution according to the evolution mechanism of the concrete temperature gradient during the pouring period.This work includes developing a temperature gradient digital monitoring system to provide feedback on the deviation from the actual value and provide a basis for timely warning and dynamically adjusted accurate temperature control,proposing the cracking control gradient index as the space and time gradient indices(a dimensionless index),and reconstructing the temperature field to the evolution of the real thermal field base on the temperature measurements in concrete,which is of great importance for the cracking control of the concrete structure.[Results]The main study results are as followed:(1)A major challenge in concrete cracking control was investigated according to complex structural properties,the continuous casting method,high temperature,high humidity,strong wind,and a high salt mist environment.(2)The monitoring data of the temperature gradient digital monitoring system indicated a certain difference in the temperature development in the center concrete and the area near the surface.The temperature in the concrete central area underwent a rapid increase and tended to be stable,stabilised temperature range of 53.60—54.50℃,and the temperature increase reached 88.16%—99.34%of the adiabatic temperature increase.The temperature near the concrete surface underwent a rapid increase and a slight decrease,peaking at 52.90℃.(3)The threshold values of the space gradient and time gradient indices were defined as-3.00—3.00℃/m and 0.002 h-1·m-1,respectively.The temperature gra
作者
安瑞楠
林鹏
陈道想
安邦
卢冠楠
林之涛
AN Ruinan;LIN Peng;CHEN Daoxiang;AN Bang;LU Guannan;LIN Zhitao(Department of Hydraulic Engineering,Tsinghua University,Beijing 100084,China;Road&Bridge International Co.,Ltd.,Beijing 100027,China;Rocket Force Academy,Beijing 100011,China;TSCON(Wuhan)Technology Co.,Ltd.,Wuhan 430074,China)
出处
《清华大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2023年第7期1050-1059,共10页
Journal of Tsinghua University(Science and Technology)
基金
中交路桥建设有限公司项目(LJLJHN-PJ2020005219-062622141)
中国长江三峡集团公司科研项目(WDD/0578)
下凯富峡水电站施工关键技术研究科技成果咨询服务项目。
关键词
超大体积混凝土
温度梯度
在线监测
连续浇筑
真实温度场
super mass concrete
temperature gradient
online monitoring
continuous casting
real thermal field
