Study On Floor Deformation And Evaluation Of Coal 11 Water Inrush Risk In Sangshuping Coal Mine

Mine water inru sh has been one of the main factors affecting coal mining safety and efficiency in China,with complex mechanism and many factors.Coal seam 11 is close to the Ordovician formation karst fissure aquifer at the bottom,and the great spatial variation in the thickness and composition of the aquifuge.11 coal mining is vulnerable to mine water inrush.Based on the geology data in the region and mine,numerical modeling,AHP(analytic hierarchy process)and vulnerability index were applied in this paper to study the law of coal floor deformation and water inrush risk in Sangshuping coal mine.And the results are as follows:(1)Based on the results of numerical modeling,when coal was mined out,the stress of the floor rock beneath goaf reduced.And the stress concentration behind the cutout and in front of the working face was concentrated.As coal mining continued,the stress reduction area expanded along the coal mining direction and vertical direction.Simultaneously,the displacement of floor rock layer increased and cracks increased.When the mining distance increased to a certain value,the stress of floor rock in the old goaf decreased.Also the displacement of floor rock decreased.Cracks in floor rock reduced.Based on the relationship between the depth of floor failure and geological factor,the thickness of the coal mining was the main factor affecting floor failure depth.(2)The analysis of aquifer,aquifer,structure and mining activities in mine water inrush accident was done.And according to the results of structural fractal research,the fold fractal dimension value of the study area is 0-1.14,with an average of 0.39;the fractal dimension value of 11 coal faults is 0-1.02,with an average of 0.114.The floor failure,depth of the 11 coal is 12-32m,with an average of 22m.(3)The weight of the factors affecting 11 coal floor water inrush was determined by the analytic hierarchy process(AHP).The aquifuge thickness was 0.2424;the aquifer water pressure was 0.208933;the floor failure depth was 0.1628;the aquifer units-inflow was 0.114998;the fault fractal dimension was 0.110325;the aquifer permeability coefficient was 0.063268;the mudstone rate was 0.0606;and the fold fractal dimension was 0.036775.(4)Based on the normalized maps and weights of various water inrush factors,the vulnerability index model of 11 coal floor water inrush was established.The risk of floor water inrush was divided into 5 classes:relatively safe area,9.64%,safer area,21.01%,transition area,25.33%,danger area,19.54%,and danger zone,24.49%.