Abstract:

Surrounding rock conditions change frequently in the fault zone, rational supporting methods for preventing collapse and large deformation according to surrounding rocks are construction key. The internal force of support structure of tunnel located in fault zone of Guanjiao tunnel is calculated. The calculation results show that tunneling in water and anhydrous conditions, the lower the grade of surrounding rock is, the bigger the difference of internal force of support structure is. The surrounding rock of fault zone of Guanjiao tunnel is summarized as Grade Ⅳ1, Grade Ⅳ2, Grade Ⅴ1 and Grade Ⅴ2, and related insitu surrounding rock deciding standard is proposed, on basis of characteristics of surrounding rock, influencing level of fault zone and water condition. The construction method of bench excavation and bench excavation with core soil are adopted after consideration.

Key words: fault zone, underground water, subclassification of surrounding rock, Guanjiao tunnel