研究目的:雁门关隧道处于恒山山脉，太古界变质岩地层，受多期构造运动影响，围岩稳定性差、大变形造成初期支护环纵向开裂，拱顶、拱脚喷混凝土剥落，钢架扭曲、折断，支护侵限甚至是二衬开裂等现象，给隧道建设带来极大的困难。通过隧道DK 121 +203-DK 121 + 175段典型大变形处理案例，分析其大变形的原因，提出合理的控制变形技术。
研究结论:(1)雁门关隧道变质岩地层虽属硬质岩，但复杂多变的地质条件加大了围岩变形破坏可能性; (2)根据现场施工及围岩量测情况采取信息化设计，对隧道各段采取针对性的措施，做到“岩变我变”，确保施工安全，有效的控制了工程成本;(3)采用快封闭、快支护、设置临时横撑、长锚杆、大管棚、分层加强初期支护以及早施工并适当加强二次衬砌等措施可以有效的控制并稳定隧道大变形;(4)本研究成果在构造复杂变质岩地层隧道设计、施工中有较广泛的应用价值。
Research purposes:Yanmenguan Tunnel lies in Archean metamorphic strata, mount Hengshan. Influenced by multistage tectonization，surrounding rock is unstable and serious deformation of this tunnel has caused cracks in primary support at the longitudinal direction. Spalling of concrete at vault and arch foot as well as steel framework contorting happened，which even went beyond the limit value and caused splitting of secondary lining, thus bringing great difficulties for tunnel construction. Combined with treatment of large deformation in DK 121 +203-DK 121 + 175 section of Yanmenguan tunnel，reasons caused large deformation of this tunnel were analyzed，and control technology on deformation was proposed in this article.
Research conclusions:(1)Although metamorphic strata are hard rocks，because of complicated geological condition， possibility of deformation and failure of surrounding rocks increases.(2)On the basis of field construction and measurement，information design is adopted in Yanmenguan tunnel construction to effectively control large deformation， thus assuring construction safety and controlling the engineering cost simultaneously.(3)Some technology are put forward such as tough supporting and rapid closing, setting temporary invert，grouting reinforcement with long rope bolt， using pipe roofs for clearance-intrusion treatment and reinforce secondary lining, etc. (4)The research results have extensive application values for tunnel design in complicated geological condition.
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