Abstract: The aim of this research is to comprehensively understand the dislocation law of creep movement of active faults. The west branch of Longpan-Qiaohou fault zone (F10-1) in Xianglushan tunnel of the Central Yunnan Water Diversion Project is taken as research background. A generalized geological model is established to investigate the dislocation law of F10-1 in the whole service period according to geological condition, rock parameters and mechanical performances. The dislocation deformation characteristics and displacement gradients are analyzed, and the stability of the tunnel is discussed in consideration of width of fracture zone and dip angle of fault. Results reveal that the dislocation patterns of the fault zone are similar, showing a sloping type. Strong dislocation disk presents a translational displacement mode, with displacement mainly occuring in the fractured area of weak rock formation. The displacement of fracture zone increases with the increasing of the service life and the fracture zone width as well as the decreasing of fault’s dip angle. According to the displacement of interface between upper influence zone and fracture zone, a large deformation in the left shoulder socket of the tunnel (except for 30° and 50°) is found. The maximum deformation is located on the left side of the tunnel. The displacement gradient presents a single peak at the fracture zone; the peak of displacement gradient increases with the growth of service life and fault dip, while reduces with the expansion of fracture zone width. The research results offer strong support for the safety construction of Central Yunnan Water Diversion Project.

Key words: tunnel, creep characteristics, dislocation mode, numerical analysis, displacement gradient, influence factor