| Huabei coal field is a main production base, which is affected by limestone karst and confined water, several times of serious water inrush accident has happended, causing great economic loss and casualty. Liangbei Coal Mine loacates at Yu County in Xuchang City, it has stop production several times since it went into production due to water inrush, and has seriously affected normal production. Due to deep mining depth and effective drainage measures, the effect of limestone aquifer in the Taiyuan Formation, which closes to coal seam floor, to coal mining is not significant, howere limestone aquifer of cambrian period becomes the main water-filled soure.Based on geological conditions of Liangbei Coal Mine, main effect factors of water inrush were analyzed and the main water-filled source was determined; then mechanical models of floor stress were builded by using the half space theory of the elasticity, calculation formulas of stress state of any point in the floor were deduced by using elastic theory, stress distribution curves of floor were drawn by means of calculation software Matlab, and floor failure depth during first weighting and periodic weighting according to Mohr-Coulomb failure criterion; Finally, with numerical simulation software FLAC3 D effects of different factors, such as face advanced distance, depth and height of coal seam and faults and its location, to stress distribution and failure depth were studied. Based on the above conclusions, combined with practical geological and hydrogeology conditions of coal face 11141, grouting transform of coal seam floor for water gushing control are put forward. The study conclusions provide theoretical foundation for safety production in coal mining above aquifer. |
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