关垭子隧道软弱围岩大变形机理分析

摘要

关垭子隧道穿越极高地应力状态软岩，施工过程中发生了大变形。在工程地质勘查、现场调研、岩石力学试验及监控量测的基础上，通过分析隧道变形特征，从隧道埋深、施工方法、围岩岩性、地应力及地下水等方面研究该隧道大变形的发生机理。研究结果表明：该隧道大变形以围岩塑性变形为主，膨胀变形影响较小，并对类似隧道的设计施工进行了展望。%Guanyazi tunnel passes through soft rock of extremely high ground stress and experiences large deformation during construction. On the basis of engineering geology investigation, on-site survey, rock mechanics experiments and monitoring measurement, this paper studies the large deformation mechanism of the tunnel by analyzing tunnel deformation characteristics in terms of construction method, surrounding rock lithology, ground stress and groundwater. The results show that the tunnel large deformation is dominated by plastic deformation with a little swelling deformation. Future design and construction of similar tunnels are also envisaged.