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Abstract 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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2014, Vol. 31 
