穿湖隧道超大尺度混凝土施工期的温度效应  

Temperature effects of super-large concrete on the construction of a tunnel through a lake

作　　者：姚潇南 张孟喜[1] 刘冰 YAO Xiaonan;ZHANG Mengxi;LIU Bing(School of Mechanics and Engineering Sciences,Shanghai University,Shanghai 200444,China;China Railway 20th Bureau First Engineering Co.,Ltd.,Suzhou 215151,Jiangsu,China)

机构地区：[1]上海大学力学与工程科学学院,上海200444 [2]中铁二十局第一工程有限公司,江苏苏州215151

出　　处：《上海大学学报（自然科学版）》2024年第2期308-317,共10页Journal of Shanghai University:Natural Science Edition

基　　金：中铁二十局集团有限公司技术开发课题资助项目(YF1901SD03B)。

摘　　要：穿湖隧道对混凝土的防渗要求很高,而混凝土的温度效应与其开裂息息相关.采用高性能双光栅温度-应变式传感器对隧道浇筑过程中混凝土的温度以及应变进行监测,分析了其变化规律.对混凝土浇筑完成后的现场情况进行了调研,发现侧墙存在裂缝且引起了渗漏.依据现场施工情况,运用有限元法对浇筑的隧道进行模拟,将数值模拟结果与现场监测数据进行对比,验证了数值模拟结果的准确性,并对影响混凝土内外温差的因素进行了参数分析.研究结果表明:混凝土入模温度越高,其内外温差就越大;入模温度升高10℃,内外温差增加1.46℃;在夏季施工时,应注意对混凝土原料进行降温处理,保证混凝土入模温度小于30℃;环境温度下降越多,混凝土内外温差就越大;环境温度下降20℃,内外温差增加6.38℃;当环境温度降低时,应注意采取保温措施;当养护过程中需要进行保温时,建议采用木模板进行养护,但拆模时间不宜早于6 d,否则会导致混凝土表面温度迅速下降,内外温差急剧增大.A tunnel constructed through a lake has high requirements for the anti-seepage properties of the concrete used,and the temperature effects of the concrete are closely related to concrete cracking.A high-performance dual-grating temperature-strain sensor was used to monitor the temperature and strain of the concrete during the concrete pouring process,and the variation law of concrete temperature and strain were analyzed.The site conditions following concrete pouring were investigated.It was found that cracks appeared in the side walls and caused leakage.Based on on-site constructions conditions,the finite element method was used to simulate the poured concrete,where the results of a numerical simulation were compared with on-site monitoring data to verify the accuracy of the numerical simulation results.In addition,the parameters that affected the temperature difference between the inner and outer walls of the concrete were analyzed.Results showed that the higher the temperature of the concrete when first introduced into the mold,the greater was the temperature difference between the completed inner and outer concrete walls.The temperature of the mold when the concrete was introduced increased by 10℃,and the temperature difference between the completed inner and outer concrete walls increased by 1.46℃.During construction in summer,the concrete raw materials should be cooled to ensure that the temperature of the concrete when introduced into the mold was less than 30℃.The greater the decrease in ambient temperature,the greater was the temperature difference between the inner and outer concrete walls.When the ambient temperature decreased by 20℃,the temperature difference between the inner and outer walls increased by 6.38℃.When the ambient temperature decreased,thermal insulation measures must be taken.Specifically,wooden formwork was recommended for maintenance when thermal insulation was required.However,the demolding time should not be less than 6 d;otherwise,the temperature of the concrete surface wo

关 键 词：穿湖隧道 超大尺度混凝土 温度效应 入模温度 环境温度 模板 

分 类 号：U454[建筑科学—桥梁与隧道工程]