Groundwater inrush within faults is an important issue in underground engineering. The process of water permeation through the soil-rock mixture has been numerically investigated. The simulated soil-rock mixture was presented with rock blocks, and filled with selected types of soil particles. The Euler-Euler method was employed with multiphase interaction. Meanwhile, the filling soil was assumed to be Bingham fluid with additional user-defined function. Then the detailed evolutions of water permeation through the soil-rock mixture were presented visually, including water distribution, water velocity field, permeation time, and penetration time. It is shown that water permeation changes with time and space in the soil-rock mixture, and the overall process of water permeation can be divided into three different stages. Moreover, major variables including water velocity, size of soil particles, and yield stress of soil were considered, which clearly influenced water permeation. Soil density showed little effect on water permeation, and the permeation time decreases with increasing water velocity. Water permeation through the soil-rock mixture is easier when the filling soil consists of smaller particles. The permeation rate of water obviously decreases with increasing yield stress. Meanwhile, different types of soils were considered with corrections on the dynamic viscosities. We found that sand and soil behave differently when water permeates through the soilrock mixture. Furthermore, selected results on water permeation were compared with the relevant studies, and reasonable agreements were reached. The presented stimulation results provide detailed information for further understanding on the mechanical mechanism of water permeation through the soil-rock mixture used in underground engineering.