English：

Based on the engineering background of largescale mud inrush in the process of Paomashan No.2 tunnel crossing F21 active fault, the timespace effect in the process of mud inrush treatment, surrounding rock grouting reinforcement, and postconstruction excavation is systematically analyzed. The research indicates that the mylonite and fault gouge in the fault fracture zone have certain selfstability and relative water resistance. The consolidation anchorage system combined with tube bundle compaction grouting and rigid tube bundles significantly enhances the integrity of surrounding rock and shortens the excavation support time from 19h to 12~13h per cycle, which secures a critical window of opportunity for the rapid excavation of the tunnel and the formation of the arch effect. The study further reveals that the tunnel excavation and support process is significantly affected by the timespace effect, which is characterized by irreversible nonlinear evolution. The exposure of the surrounding rock of the tunnel face for 12~18h is the critical period of the initial support. The convergence of surrounding rock is positively correlated with the exposure time. The maximum cumulative settlement is 45mm, and the settlement rate does not exceed 004mm/d. In the construction, the early deformation of surrounding rock and the extrusion deformation of the tunnel face should be considered comprehensively, and the microbench method combined with strong support and early closure measures should be adopted to effectively control the deformation of the surrounding rock in the rear.