Research On Regularities Of Water Flowing Fractured Zone Development In Slicing Excavation Of Thick Coal Seam In Barapukuria

The research on the development height and law of the water flowing fracture zone is the key point of mining under the water body,this paper is aimed at mining the thick coal seam under the super water-rich loose water-bearing sand layer of Upper Dupi Tila(UDT)formation of Barapukuria Coal Mine,the development law of water flowing fractured zone in layered mining of thick seam under UDT aquifer is systematically analyzed by means of numerical calculation,field detection and theoretical analysis.Based on the analysis of the geological and mining conditions in the Barapukuria Coal Mine,AHP method was used to evaluate the influencing factors of safe mining under UDT aquifer,and it was determined that geological structure,mining width,position and thickness of aquifuge were the main factors affecting the safe mining of thick coal seam under UDT aquifer.Through key stratun theory was calculated the structural stability of the rock beam,the mining thickness of first-layer is not more than 3.2m.Applied to FLAC3D numerical calculations method simulate and analyze the development law of water flowing fracture zone in layered mining of thic k coal seam.,the numerical simulation experiment results shows that the key structure is not unstable due to the height limit of first layer.second slice mining makes the key structure unstable,and the overlying rock ailure height increased significantly.On the moment,second layering to arranged coordinate slicing staggered distance made the first slice coal pillar in the upper stratified section loses its supporting force,the overlying strata in the upper stratified section becomes a whole subsidence movement.The height of water flowing fracture zone in the second and third layer mining area was detected by surface detection borehole.The detection results show that the height of the third slice water flowing fracture zone is 232.02m compared with the second slice(215.94m)that increase of only 7.4%.The conductivity of water fracture is enhanced from top to bottom.According to the result of detection and analysis of simulation results,first and second layered water flowing fractured zone height and mining thickness is linear relationship,while third layered into power function relationship,build the Barapukuria mining thick coal seam layering mining height of water flowing fracture zone predict model,provide the thick coal seam layering mining safety pillar under water-bodies determination method.Relevant researches have provide a reference for the formulation of the safe thick coal seam mining scheme under the UDT aquifer of Barapukuria Coal Mine.