索塔承台大体积混凝土温度控制研究  

Study on temperature control of mass concrete for tower pile cap

作　　者：贺云 贺金龙 余棚 张本蛟 傅旭东[1] HE Yun;HE Jinlong;YU Peng;ZHANG Benjiao;FU Xudong(School of Civil Engineering Wuhan University,Wuhan 430072,China;CCCC-SHEC First Highway Engineering Co.,Ltd,Wuhan 430055,China;China Gezhouba Group Co.,Ltd,Wuhan 430032,China)

机构地区：[1]武汉大学土木建筑工程学院,湖北武汉430072 [2]中交二公局第一工程有限公司,湖北武汉430055 [3]中国葛洲坝集团股份有限公司,湖北武汉430032

出　　处：《铁道科学与工程学报》2020年第2期372-378,共7页Journal of Railway Science and Engineering

基　　金：国家自然科学基金资助项目(51378403,51978540)

摘　　要：由于索塔承台混凝土体积大,水化热高,导致内部温度、内表温差过大,很容易产生温度裂缝,因此有必要对其进行温度控制。采用线单元解耦算法对榕江大桥索塔承台混凝土不同浇筑方案进行数值模拟,分析浇筑厚度、冷却水及冷却水温度对混凝土温度、应力的影响,从而选择合适的浇筑及温控方案,并将现场实测数据与计算数据进行对比。研究结果表明:混凝土内部温度通常在浇筑后第3~4 d达到峰值,降温速率小于升温速率;通冷却水可降低最高温度3℃~4℃,且可增加混凝土降温速率;但降低冷却水温度对混凝土内部温度影响有限,且会增大混凝土内部应力;根据数值计算结果,承台采用分3层浇筑、冷却水温度为25℃的施工方案;实测承台第1浇筑层内部温度最大为65.8℃,内表温差最大为24.3℃,内部温度、内表温差和应力均未超过规范允许值,温控方案合理。研究成果对索塔承台大体积混凝土的浇筑及温控具有一定参考价值。The large volume and high hydration heat of the concrete of the tower pile cap can cause not only extreme internal temperature but also extreme difference between internal temperature and surface temperature, which would easily induce temperature cracks. Hence it is necessary to control its temperature. The linear element decoupling algorithm was used to simulate the different pouring schemes of the tower pile cap concrete of Rongjiang bridge, and the influence of pouring thickness, cooling water and cooling water temperature on the concrete temperature and stress were analyzed so that the appropriate pouring and temperature control scheme was selected. The field measured data were compared with the calculated data. The following conclusions are obtained: the internal temperature of concrete usually reaches its peak on the 3 rd to 4 th day after pouring, and the cooling rate is lower than the heating rate. The cooling water can reduce the maximum temperature by 3 ℃~4 ℃ and increase the cooling rate of concrete. However, reducing the cooling water temperature has limited influence on the internal temperature and increases the internal stress of concrete. Based on the numerical results, the construction scheme with three pouring layers and 25 ℃ cooling water was adopted in the pile cap. The maximum internal temperature of the first pouring layer of pile cap is 65.8 ℃, the maximum temperature difference between the inner and surface temperature is 24.3 ℃. The internal temperature, the temperature difference and the stress do not exceed the standard allowable values, so the temperature control scheme is reasonable. The research results have certain reference value for the pouring and temperature control of mass concrete in the tower pile cap.

关 键 词：索塔承台 大体积混凝土 冷却水 温度控制 数值模拟 

分 类 号：U445[建筑科学—桥梁与隧道工程]