Failure Characteristics of Floor Mining-Induced Damage Under Deep Different Dip Angles of Coal Seam

To research the failure characteristic of coal seam floor with a certain dip angle and the monitoring and prediction of water inrush. Taking the coal mining face in Xinhong 3(#)Mine as the study object, a water inrush model of water floor under pressure of six different angles in coal layers was established. Using FLAC(3D) numerical simulation as a method of making a comprehensive comparative study about the depth and range of the mining failure depth of different angle in coal layers. The study results showed that the damage from of the floor in deep area after mining was quite different from the one in the shallow area. The plastic failure depth of floor increases with the increase of working face width, the vertical stress of the bottom plate of the working face is increasing gradually; the plastic failure depth of floor increased to the maximum and then decreased with the increase of coal seam dip angle. It will reach the maximum failure depth at 30 degrees, and is easy to occur shear failure. The maximum failure depth is up to 28.77m, which is very close to field monitoring result, it can provide the basis for preventing water inrush of mine caused by deep mining floor.