This study focuses on assessing the stability of a water-saturated fault fracture zone in anticipation of tunneling activities, specifically examining the Bifeng Temple Tunnel as part of the high-speed rail link between Fuzhou and Xiamen. The research integrates the stress-seepage interaction within the rock mass to simulate the behavior of permeability, flow rate, and water pressure during tunnel excavation in the presence of water-rich faults, utilizing the COMSOL Multiphysics software. The study further evaluates how changes in the proximity of the tunnel to the fault zone impact seepage characteristics. Findings reveal that the end effect leads to a high permeability zone at the tunnel's forefront. Notably, when the tunnel-fault distance (d) is between 1 to 5 m, there is a significant increase in seepage parameters k and v, coupled with a swift decrease in water pressure (p) within the fault, suggesting a heightened risk of water inrush incidents. As the excavation face nears the fault, the seepage indicators at monitoring point A surpass those at B, signifying the tunnel face as a pivotal juncture for non-Darcy and turbulent flows. These insights offer a scientific foundation for the development of strategic precautions in tunnel engineering within water-bearing fault zones.