Water inrush hazard, which is the most frequent geo-hazard encountered by underground engineering, particularly when passing through water-rich geological formations. Understanding the incubation, evolution, and occurrence of water inrush, as well as the reinforcement approach in tunnels, is crucial for disaster mitigation and risk control. To this end, we systematically put forward our solutions to this problem by giving full play to the advantages of discontinuous deformation analysis (DDA). The practical application of our numerical solutions, starting from the hydro-weakening origins, progressing to the water and rock inflow, and culminating in the grouting process for disaster mitigation, demonstrates that our work provides a comprehensive understanding of the evolution mechanism of water inrush disasters.