Experimental Study On Water Inrush Mechanism Of Fault From Coal Seam Floor In Zhaogu No.2 Mine

Water inrush in coal mine is the main disaster which influences our country's safe product. Fault water inrush in floor is the main form of water inrush in coal mine. The main reason which causes floor water inrush is that mining makes floor fault activated and formed a channel to guide water which connects mining space and aquiclude. This thesis used theoretical analysis, analog simulation and numerical simulation, regarded floor fault of Zhaogu No.2 mine as research target, studied the main factors of floor fault inrush and activated water inrush law of floor fault and got the research conclusion below:(1)The mutual affect of water source, water pressure, aquiclude and geological structure and other factors that influence water inrush and fault was analyzed. Results shows: Fault and water inrush factors mutually promote in the process of water inrush. The existence of fault aggravates the effect of water inrush influencing factors in the process of water inrush. Water inrush influencing factors promote the activation of fault to some extent.(2)From the view of mining stress and hydraulic fracturing to carry out mechanical analysis, criteria formula of fault activation in the affect of mining stress was derived. Curve relationship between critical water pressure which caused by fracture damage extend in the process of hydraulic fracturing and vertical stress, lateral pressure coefficient, pressure-shear coefficient and fracture dip angle.(3)Analog simulation was adopted and activated law and characteristics of floor fault in the influence of mining was studied. Experimental results show: with the influence of mining, the process of floor fault activation can be divided into stationary phrase, initial phrase, activated phrase. Fracture which is at the surrounding of fault and work face floor plastic damage zone get connected at initial phrase, which is the omen information of fault complete activation. At the activated phrase, fault slides and damages and the face of fault is opening, therefore, guide water channel formed and water inrush accident occurs.(4)Numerical simulation was used to research the influence of floor fault to floor water inrush. The simulation results show: plastic damage zone near the fault becomes large gradually with the forward of work face to fault. When the plastic damage zone which is under goaf connects damage zone near fault, water inrush channel forms and water inrush happens.