Monitoring and numerical simulation of water inrush pathway caused by coal mining above karstic confined aquifer with high water pressure

Mining-induced floor failure and formation of water conducted pathway is the necessary conditions for water inrush in coal mine, which are the basis for monitoring and predicting water inrush. In order to study the formation and evolution of floor failure and water conducted pathway caused by coal mining above karstic confined aquifer with high pressure in Xinyi coalmine, Henan province, China, field monitoring and numerical simulation methods are introduced in this paper. Subsequently, the variations of electrical resistivity, stress and pore water pressure of floor during mining process are analyzed. The result shows that the floor failure caused by coal mining under karstic confined aquifer with high pressure is influenced significantly by advanced supporting stress of coal mining and the failure depth of floor of panel 11011 is about 25 m, which is greater than general empirical value. Based on fluid-solid coupling theory, the established numerical simulation model of mining-induced floor failure can reflect the influencing factors of floor failure more accurately and objectively; and the maximum failure depth is up to 23.75 m, which is very close to field monitoring result. The variations of electrical resistivity, stress and pore water pressure can better reflect the whole process of mining-induced floor failure formation, water inrush pathway evolution and water filling. The conclusion indicates that the above-mentioned parameters can be used as the precursor information for monitoring and short-term predicting the water inrush hazards in coalmines.