提高侵蚀环境下山岭隧道衬砌混凝土耐久性施工对策研究

Research on the Construction Solutions to Increase the lining Concrete Durability of Mountains Tunnel under Aggressive environments

  • 摘要: 通过调查发现,我国既有山岭隧道结构耐久性普遍不足,许多隧道运营后不久衬砌结构就出现了开裂、渗漏水、溶蚀结晶、甚至出现拱顶掉块,造成隧道结构耐久性不足,其原因有设计原因也有施工方面的原因。文章针对既有隧道的病害表现,分析了隧道衬砌耐久性不足在施工方面的原因,并提出了解决新建隧道衬砌混凝土耐久性的主要施工对策:采用多元复合胶凝材料及合适的混凝土搅拌工艺;采用低水胶比、低用水量和高性能减水剂;采用先进的灌筑和振捣工艺、合理的养护技术及拆模和养护时间等。

     

    Abstract: Through the survey it is found that there is serious shortage of durability in existing mountain tunnel structures, and defects including cracking,leak, crystal dissolution and even concrete spalling of the arch in many tunnels’ second linings soon after the operation of these tunnels in China. Insufficiency of duability results from not only the design but also the construction. According to the representation of existing tunnels’ diseases, this paper analyses the construction reasons which result in the insufficient durability of the tunnels’ second linings, and proposes construction strategies to solve thelack of the second lining concrete durability of newly-built tunnel structure concrete. The specific measures are using multiple composite cementitious materials, adopting proper concrete mixing process, using low water-cement ratio, adopting small water usage and effective superplasticizer, using advanced pouring and vibrating technology, taking reasonable maintaining technology and forming removal and curing time. These measures may provide some references for new tunnels’ construction.

     

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