某轨道交通地下车站叠合墙结构的裂缝控制技术研究

The Research on the Crack Control Technology of Composite Wall Structure of an Underground Metro Station

针对某地铁车站叠合内衬墙,属于薄壁超长结构,受底板及地连墙混凝土的强约束等特点,水化温升、温降速率较大,且降温过程中极易引起混凝土开裂,从而导致墙体结构抗渗性能降低。通过双掺矿物掺合料与温控防渗抗裂剂,配制出具有较低水化放热速率,微膨胀的高抗裂内衬墙C35混凝土,通过热物理学、力学及体积稳定性表征抗裂性能,同时结合有限元仿真计算与实体结构的监测分析,拆模后表面未发现裂缝,该研究为同类工程的裂缝控制提供宝贵经验。

In view of over-length and thin-walled structure of composite wall of a metro station, the problem of concrete cracks is easy to occur during the temperature decline process due to the factors such as strong constrains of baseplate and underground diaphragm wall, high hydration temperature rise, rapid temperature drop rate. What＇s worse, the cracks will lead to the reduction of wall structure＇s anti-permeability. By using mineral admixture and anti-cracking agent,the C35 concrete with low exothermic rate and s micro expansion ability was obtained in this research.The thermophysics, the mechanics and the volume stability are measured to character the anti-cracking ability. At the same time, the finite element simulation and actual engineering structure monitoring are combined to analyze the result. There is no crack found after dismantle on the wall surface, which provides valuable experience for the similar engineering.