摘要
石家庄复兴大街白佛隧道为明挖隧道,共需浇筑混凝土15万m3。为解决冬季-15℃~0℃环境下大体积混凝土施工质量问题,采用理论分析结合现场测试的手段,对不同混凝土入模温度和各种保温措施进行对比分析,提出适用于白佛隧道冬季混凝土施工的保温技术。研究结果表明,当热水温度在40℃~60℃时,白佛隧道冬期C45混凝土出机温度在11.7℃~14.6℃之间,入模温度在7.4℃~9.7℃之间;对隧道底板、侧墙和顶板分别采用聚氨酯+电热毯+棉被、热风机和电热毯+聚氨酯+棉被方式进行保温处理后,混凝土内部与表面的温度均随着时间的延长呈先增大后减小的趋势,同时内部与表面混凝土温度均大于0℃、混凝土表面未出现裂缝。在第7 d时,隧道底板、侧墙和顶板的混凝土抗压强度分别为36.3,36.1,35.7 MPa。
The Baifo Tunnel on Shijiazhuangs Fuxing Street is an open-cut tunnel project requiring 150000 m3 concrete.In order to address the quality issues associated with large-volume concrete construction in the winter environment ranging from 0 to-15℃,a combination of theoretical analysis and on-site testing was employed to compare and analyze the impact of concrete placement temperature and different insulation measures.A thermal insulation technique suitable for winter concrete construction in the Baifo Tunnel was proposed.The research results indicate that for C45 concrete used in the Baifo Tunnel during winter,the temperature upon discharge from the mixer ranged from 11.7℃to 14.6℃with the temperature fluctuation during concrete placement between 7.4℃and 9.7℃.The tunnel floor,side walls,and ceiling were respectively treated using a combination of“polyurethane+electric heating blanket+quilt”,“hot air blower”,and“electric heating blanket+polyurethane+quilt”,and the measured temperature of the concrete interior and surface showed an initial increase followed by a decrease over time.Both the interior and surface temperatures remained above 0℃,and no cracks were observed on the concrete surface.Additionally,on the 7th day,the compressive strength of the concrete in the tunnel floor,sidewalls,and roof reached 36.3 MPa,36.1 MPa,and 35.7 MPa respectively.
作者
李敏方
王伟
崔之靖
陈武
徐鹏
LI Minfang;WANG Wei;CUI Zhijing;CHEN Wu;XU Peng(China Communications Construction Co.,Ltd.,Beijing 100088,China;China First Highway Engineering Co.,Ltd.,Beijing 100024,China;Shijiazhuang Tiedao University,Shijiazhuang 050043,China)
出处
《铁道勘察》
2024年第3期156-161,共6页
Railway Investigation and Surveying
基金
国家自然科学基金项目(52108331)
河北省高等学校科学技术研究项目(ZD2021096)。
关键词
明挖隧道
市政隧道
混凝土
冬季施工
保温技术
抗压强度
open-cut tunnel
municipal-service tunnel
concrete
construction in winter
insulation technology
compressive strength
