| China has rich coal reserves and more coal production,but most of the raw coal comes from underground mining.The coalfield complex geological conditions in China,about 27% of the coal reserves are seriously threatened by water,geological disasters occur frequently in mining poses a serious threat to the safety production of coal mine.Sihe coal mine 3 coal seam mining is threatened by water,the more obvious,subsided column,water conducting structure has become the constraints of Sihe Coal Mine No.3 coal mining safety production factors.Therefore,this paper through the collection,acquisition of Sihe mine before detailed hydrogeological drilling and geophysical data,combined with previous drilling,geophysical and chemical characteristics of water,karst development law research;through the study of Sihe coal mine collapse column development mechanism,the geological background,the distribution rule and characteristics,and on the basis of wells study on collapse column detection,summarization of geological characteristics of collapse column filling;using geophysical methods under various wells combined detection of Sihe Coal Mine w2301 West wells working face X2 collapse column is studied;the numerical simulation technology of coal seam X2 collapse column process was numerically simulated,analyze and evaluate the safety the risk of collapse column by X2 coal seam and after water inrush.The main research results are as follows:(1)The distribution of subsided columns in the west well area of Sihe mine is more closely related to the geological structure conditions,and the collapse column is distributed centrally along the fold crank and fault strike.The collapse column development zone mainly located in the fold direction and karst water in the strong runoff zone of the oblique cross position,with the distribution of concentrate in groups.(2)The Si Hexi minefield has explained 8 collapse columns through a three dimensional earthquake.In the west well area of Sihe coal mine,there are 4 oval columns,2 oval circles,2 irregular shapes,and the profile features are all funnel shaped.(3)Through various geophysical methods under well combined detection,the X2 karst collapse to No.3 coal roof 20~30m column,oval fall,long axis 75 m short axis 50 m,collapse column internal crushed rock,with rich water,rich water relatively in No.9 coal seam position,in the No.15 coal seam and the bottom part X2,the collapse column and Ordovician limestone hydraulic connection is weak or no hydraulic connection.(4)Through the numerical simulation technology,the supporting pressure of the face in front of the work face moves forward with the working surface before it uncovers the collapse column,forming the support pressure of the forward moving,and the vertical stress increases with the decrease of the coal pillar.In the process of advancing the collapse column,the degree of plastic breaking of the collapse column X2 is obviously larger than the plastic scope of the normal rock strata.The active fissure of the subsided column develops down the edge wall of the collapse column,the development depth is about 57 m,and the subsided column has a heave at the edge,the stress of the bottom plate is greatly released and the stress is reduced,which provides the condition for hydraulic upwelling,and it is likely to be connected with the lower orot water if the side wall of the subsided column continues to activate.The risk of water inrush is caused. |
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