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Abstract Pre-reinforcement technology of tunnel face bolt is studied through large-scale similarity model test. A series of forepoling pre-reinforcement model tests around the tunnel as auxiliary contrast analysis are conducted to confirm the characteristics and mechanism of tunnel face bolt. By analyzing the model test results and stress field characteristics，the conclusions can be drawn as follows：(1) It is verified that tunnel face bolt improves the stability of the surrounding rock，relying on longitudinal arching effect by means of load transferring and distributing. In addition，the extent of longitudinal pressure arch for the case of face bolt reinforced is less than that of the case of non-reinforced tunnel and small pipe reinforced；(2) The excellent control effects of surrounding rock stress in front of tunnel face in horizontal and vertical directions by tunnel face bolt are the basic premise of forming effective longitudinal bearing arch. So the longitudinal pressure arch possesses great ultimate bearing capacity. (3) The tunnel face bolt can effectively control the extrusion deformation of tunnel face. The study results have important engineering significance for the construction of tunnel with weak surrounding rock.
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Received: 17 March 2011
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2011, Vol. 30 
