Grouting diffusion and seepage field evolution in shaft surrounding rock by two-phase flow and sedimentation modeling

Grouting is a key way to prevent and control water inrush disasters in mines, which can actively modify the rock mass. However, achieving efficient transformation of the original rock seepage field to prevent water inrush is still a fundamental issue, especially since the evolution law of the rock seepage field under the two-phase action of water and grouting slurry is unclear. Therefore, a permeability evolution model for porous media considering two-phase seepage–deposition interactions was developed. Numerical simulations were conducted to analyze the temporal and spatial evolution of rock permeability and the regional seepage field during grouting in structurally influenced areas. The effects of grouting parameters on these processes were also investigated, and the performance of different grouting schemes was compared. The results indicate that rock permeability decreases nonlinearly over time, with a rapid initial decline followed by slower rates of change. Grouting can alter both the velocity and direction of groundwater flow. Increasing grouting pressure significantly reduces rock mass permeability, while low water–cement ratio slurry proves more effective for high-permeability rock masses, exerting a greater influence on the seepage field within the diffusion range. High-pressure grouting with medium-to-high water–cement ratio slurry in aquifers reduces the average seepage velocity by 37.92%, delivering the best overall performance despite stricter application requirements. Fault grouting emerges as the second most effective strategy, combining good performance with broader applicability. Surrounding rock grouting, however, has a more limited impact on the seepage field.