Numerical analysis on water inrush catastrophe of concealed collapse column of floor under mining

Abstract

In order to study the characteristics and evolution for water inrush catastrophe of concealed collapse column of floor under mining, a concealed collapse column project was taken as the background. The process of water inrush catastrophe of concealed collapse column under different driving distances of working face was reproduced by considering fluid-solid coupling effect and dynamic change characteristics of surrounding rock permeability coefficient. On this basis, the influence of development height and water pressure of concealed collapse column on coal floor water inrush was studied. The research results show that: when the working face is excavated through the collapse column, the water-conducting fissure channel between the collapse column and the coal seam starts at the front of the top of the collapse column and ends at a position about 20 m from the coal seam floor to the center of the collapse column. With the excavation advancement of working face, the water inflow of coal floor is generally distributed in an “S” curve, which increases fastest when the working face is close to and passes through the collapse column, and gradually stabilizes after the working face is 35 m away from the center of collapse column. The closer the collapse column is to the coal bottom, the faster the time point at which water inflow of coal seam floor increases rapidly and the greater the range of its growth interval. At the same time, the amount of coal floor water inflow is exponentially decayed with the distance from collapse column top. When the driving distance of working face is same, the water inflow of coal floor has an exponentially increasing relationship with the water pressure of collapse column.

Keywords

• concealed collapse column
• water inrush catastrophe
• flac3d
• permeability coefficient
• water inflow