The Technology And Engineering Countermeasures Of Safety Mining Under Water-inrush Threat Conditions

The hydrogeology conditions of North China Coalfield are complex.With the miningdepth increasing, a lot of mine in varying degrees are under the threat of sudden flooding.The theory and technology research of mine safety mining under flood threat has alsobeen the hot spots of research. This paper studies hydrogeological conditions in the miningarea, water-inrush risk analysis, deformation and dynamic response characteristics duringthe mining process by combining numerical simulation and theoretical analysis methods.Taking No.3mining region of Danhou coal mine in Yu County of Hebei Province asengineering background, based on two-dimensional seismic data and geological data, theaquifers are defined by the analysis of the hydrogeological conditions. In order to showthe relative relations of the aquifers impermeable stratum and coal seams in space visually,,based on the geological logging data, the3D visual hydrogeology model of No.3miningregion is obtained by using SURPAC. The impermeable layer thickness contour mapsnearby5&1coal seams working areas and impermeable layer ranges were given bystatistical analysis and calculation, the area and volume of the flow field were determined,and the rational mining sequence was proposed. In combination with the hydrological andgeological analysis and the3D visualization model, the numerical calculation model ofmining area is built through the MIDAS/GTS-FLAC3Dcoupled modeling technology. Forthe5&1coal seams1to be mine in mining region, considering the influence of aquifers,the nonlinear mechanical response characteristics and variation of fluid are studied underdifferent mining sequences, through the fluid-solid coupling calculation. After Referenceto the water-inrush history in the mining area, the causes of water-bursting in tunnelconstruction period are studied under the influences of the fault structure and the confinedwater. Through the change of bearing water pressure, thickness of impermeable layer, faultthrow and dip angle of fault factors, numerical simulation analysis is carried out indifferent conditions. The fundamental mechanism which every factors induce water-inrushby is revealed, and the widths of security coal pillar are briefly delineated under differentconditions. Finally, by using the AHP method, the factors which can induce water-inrush in No.3mining region are analyzed in weight, and the engineering countermeasures areput forward after water-inrush risk evaluation.The study on water-inrush analysis and prediction, which can provide theoreticalbasis and technical support for mining safely of the mining region and the safeguard ofhigh efficiency mining,undoubtedly has important realistic meaning and practical value.