地铁盾构管片预埋槽道防腐技术研究

Study on Anticorrosion Technology of Embedded-channel in Shield Segment of Metro

地铁盾构管片预埋槽道因处在隧道封闭潮湿的环境中,加之有些地区因地材和水质原因,混凝土具有的一定强碱性,这对预埋槽道的防腐技术提出了一个更高的要求。但是国内至今也没有关于地铁盾构管片预埋槽道的国家技术标准,已使用或者正使用预埋槽道的地铁隧道工程中,设计对预埋槽道的绝缘、防腐能力要求过于笼统模糊,使其无法进行定量检测,从而难以保证其绝缘和防腐质量。通过工程实践以及理论研究,对地铁盾构管片预埋槽道的绝缘层、防腐层提出具体的技术指标和应用环境,以便指导预埋槽道的设计、制造和检测,并为建立国家规范提供技术支持。研究结论:在考虑地铁隧道杂散电流的情况下,预埋槽道绝缘封闭层应通过试验检测其绝缘性、阻燃性、软化点等9个指标来确定其性能,且采用绝缘层封闭层+铝锌多元合金共渗防腐是可行的。在不考虑地铁盾构隧道杂散电流的情况下,采用镍锌合金共渗防腐是可行的。

There has been an increasing demand for the anti-corrosion ability of the embed-channel in shield segment because tunnel is located in such a closed wet environment that the concrete has certain strong alkaline due to the influence of local materials and groundwater. But there has been no national technical standard for embed-channel. The current anti-corrosion and insulation requirements in design are too ambiguous to conduct quantitative test, and thus it is difficult to evaluate the quality of embed-channel coating. Based on practices and theoretical researches,technical indicators and specific application conditions of the insulation layer and anti-corrosion layer are defined to guide the design,manufacturing and testing of embed-channel,and to provide technical support for the establishment of national technical specifications. The research concludes that nine indicators such as insulation,flame retardancy and softening point should be used to evaluate the performances of the insulation layer of the embedded channel,and the combination of insulation layer,sealing layer and aluminum-zinc alloy is applicable for anticorrosion. And it is feasible to adopt nickel-zinc alloy corrosion protection irrespective of the stray current in shield tunnel.