江阴靖江长江隧道工作井侧墙抗裂防渗研究与应用

为解决工作井侧墙混凝土收缩开裂及侧墙顶部与环框梁结合部位不密实而引起的渗漏问题，首先，采用考虑材料、结构、环境、施工等多因素耦合机制模型，JP2]量化评估混凝土开裂风险，提出抗裂性控制指标； 然后，通过综合运用黏度调控、水化历程与膨胀历程双重调控技术，实现了工作井侧墙中低胶材混凝土自密实性能与抗裂性能协同； 最后，结合入模温度控制、冷却水管、控制布料间距与浇筑速率以及保温保湿养护等工艺措施，提出了超长大体积、分步浇筑的工作井侧墙抗裂防渗成套技术方案。工程应用结果表明，工作井侧墙与环框梁结合密实，单边最大长度为53.6 m、一次性浇筑累计长度达120 m、厚1.5 m的工作井侧墙未出现裂缝及渗漏。

Research and Application of Anticracking and Seepage PreventionApproaches for a Working Shaft Sidewall Concrete in Yangtze River Tunnel in Jiangyin,Jingjiang, China

A multifield coupling mechanism model that simultaneously considers materials, structure, environment, and construction factors is adopted to quantitatively evaluate the cracking risks of sidewall concrete and prevent leakages caused by the shrinkage cracking of working shaft sidewall concrete and the uncompacted combination between sidewalls and a ring frame beam. Then, anticracking control indices are proposed. second, Investigations reveal that the self compacting and anticracking performances of sidewall concrete with medium and low cementitious materials are well realized by adopting control technologies of viscosity and double regulation on hydration and expansion history of the concrete. Finally, the construction measures, including controlling mold temperature using a cooling water pipe, optimizing the pouring spacing and rate, insulation and moisture curing, a complete technical scheme of anticracking and seepage prevention of the working shaft sidewall concrete with large volume, and stepwise casting, are proposed. the engineering application results show that: The sidewall concrete is tightly connected with a ring frame beam, no crack and leakage appears in the working shaft sidewall with a maximum length of 53.6 m, and the cumulative one time pouring length and thickness of 120 and 1.5 m, respectively.