Analysis on Water Inrush Prevention Mechanism of Paste-Filled Floor above Confined Water

To study the influence of filling step and advancing distance on the deformation and failure of a working face floor, a mechanical model based on elastic foundation beam theory is established. The deflection and bending moment curves of the floor under different filling steps and advancing distance are obtained by Maple. Then, a fluid–solid coupling model of paste-filling mining on confined water is established by FLAC3D. The effects of different filling steps and advancing distance on the floor displacement, stress, and plastic zone of the floor are analyzed. The results show that there is a “concave” quadratic relationship between the filling step and the maximum displacement of the floor, and there is a “convex” quadratic relationship between the advancing distance and the maximum displacement of the floor. The maximum stress of the floor increases linearly with the increase in filling distance and tends to be stable with the increase in advancing distance. Moreover, the increase in filling steps will lead to the continuous increase in longitudinal failure. This study could guide paste-filling mining above confined water.