Abstract: There exists a great risk of geological disasters such as the jamming induced by large deformation and collapse of surrounding rock when an opened TBM passes through fault fracture zones.Taking the Xianglushan tunnel in the Central Yunnan Water Diversion Project as an example, the mechanical response of surrounding rock, the reaction change of TBM structure and the stress state of support system in the excavation process are analyzed by three-dimensional numerical simulation.The results show that:(1) during tunnel excavation, the fault zone increases the rock deformation within a certain influential range, and the plastic zone tends to develop along the soft-hard interface between the fault zone and the intact stratum;(2) in the fault zone, the convergence deformation of surrounding rock and the plastic zone range at the arch bottom are greater than those in intact rock zone, so the TBM faces the risk ofdowndip of headcutter and floor heave;(3) the opened TBM jamming risk in the fault zone is mainly headcutter jamming;(4) the long-term stability of tunnel surrounding rock in fault zone cannot be insured only by the initial support, so it is urgentto construct secondary lining in time to share surrounding rock pressure.