Study On Reasonable Retainment Of Fault Waterproof Pillar Based On Hydro-fracturing Method

The coal is one of our country’s main energie, however, as the depth of mine is increasing continuall, the water disaster are threatening Coal Resources more seriousl, and the water disaster has became a serious problem which influence coal mine safety production. The most coal mining water inrush have relationship with fault, leaving fault waterproof pillar is the important measure of preventing water-burst. So, the study of leaving fault waterproof pillar is significative. In this paper, the tensile strength of coal seam of Dong Shan coal mine was measured with the method of hydro-fracturing, it provides scientific basis for the leaving fault waterproof pillar. The main endeavor and contributions of the dissertation are as follows:(1)、This paper describes mechanism of water-inrush through fault,"activation" is the necessary conditions for fault when it became water inrush channel, but no sufficient condition. Fault crack opening and connected is the sufficient condition for fault when it became water inrush channel.(2)、This paper summarizes mechanism of the method of hydro-fracturing and analysis characteristics of the hydraulic fracturing of coal seam, through the laboratory test and, it is reasonable that the tensile strength of coal seam was measured with the method of hydro-fracturing.(3)、This paper study tectonic position of Dong Shan coal mine, it is obtained that fault is the main channel of water inrush. Some measures was implemented,such as, Grouting transform technique、surveying water technique and leaving waterproof pilla, and the technique of leaving waterproof pillar has been more applied.(4)、The tensile strength of coal seam which in the71505face、the51519face and750conveyance road of Dong Shan coal mine was measured with the method of hydro-fracturing.(5)、In this paper, based on comprehensive consideration of the influence of tensile strength of coal seam、ground pressure、tectonic stress and water pressure on waterproof pillar, the dimensions of waterproof pillar was determined. The parameter reduced the width of waterproof pillar, recoverable reserves of coal was increased significantly. It has wide application prospect.(6)、Two-dimensional numerical model was established by means of ANSYS, in the process of excavating of hanging wall and footwall of the fault, the stress--strain laws in the fault nearby was simulated, it was further verified that excavating of hanging wall was more to activate the fault than footwall. it has important values for determining the dimensions of waterproof pillar of fault. Practice proves that strength parameter of coal layer obtained by methods of normal position of hydro-fracturing conforms to reality, the equipment is simple, measurement data is direct and is typical, so it has strong usability, the measurement period is short, this method has broad development perspective and application scope in aspect of water disaster in coal mine, it has important meanings to scientifically set water-proof pillar of fault.