The Research of Floor Water-irruption Numerical Simulation for Coal Mining above Confined Aquifer

With the increase of mining depth, the problem of instability in the floor with confined water has become the major factor that threaten the production safety of coal mine. Floor water invasion in coal mines is a complex problem, which is influenced by many factors. It is affected not only by the surrounding rock properties, strata combination and geological faults, but also by the aquifers, impermeable layer, head pressure, coal mining methods and so on, so it is difficult to accurately predict it. The paper has a conclusion on the mechanism of water inrush, analysis of factors affecting the water inrush. Then application of numerical calculation software FLAC3D simulates seam floors under underground pressure and water pressure, the effect on broken depth, damage range, failure property and process. Water burst conditions and position is predicted in the floor. The research shows that reducing mining room can effectively reduce deformation, failure and movement of roof, floor and surrounding rock. Confined water in the floor is the important forces of stripe failure floor aquifers. With the increment of the pressure of the artesian water, failure strength and range of floor will is enhanced by mining. With the coupling effect of mine pressure and hydraulic, the greatest change position of displacement and stress of floor strata is present to the nearby of goaf deep and coal wall of extracting coal face. Floor water invasion largely occurs in these road segments..