Mechanism of Water Inrush of a Deep Mining Floor Based on Coupled Mining Pressure and Confined Pressure

Abstract

We studied the water inrush mechanism in deep mines using experiments to determine the full stress–strain permeability of different lithologies in deep coal seam floors. We also performed numerical simulations of rock floor failure and confined water uplift variation, fracture evolution, permeability variations of coal seam floor failure, and monitored confined water uplift. The results show that water inrush is related to the coupling of mining pressure and water pressure, which expand after unloading, similar to the way rocks soften in stress–strain permeability experiments after peak stress. This conclusion has been confirmed by field drilling, water injection tests, and numerical simulations. The water-bearing layer of the floor strata can be modified (strengthened) by grouting to reduce confined water flow. Technical measures can be taken to divert pressure from and reduce damage to the floor strata and thereby prevent water inrush through the coal floor.