| The technology of retaining laneways has been applied in some areas of China,but mainly concentrated in thin and medium thick coal seams.There are relatively few engineering practice activities for the fully mechanized top coal caving face of thick coal seams.Based on the actual geological conditions of the 42106 face of the Qinggangping Coal Mine,this paper uses theoretical analysis,laboratory research,numerical simulation and field tests to carry out a variety of research methods for the stability control of surrounding rock in the retaining tunnel along the fully mechanized caving face.Systematic research,the main research results are as follows:(1)the movement characteristics of the overburden along the roadway of the fully mechanized roadway are analyzed,and the stability control of the surrounding rock along the roadway is analyzed in mechanics,and the width and strength of the backfill along the roadway are preliminarily determined.(2)through the analysis of the mechanical model of the established supporting system along the roadway of the fully mechanized roadway,it can be seen that with the increase of the top coal rigidity,the roadside supporting system stiffness increases and the top coal transmission capacity increases.The effects of the thickness of top coal and the thickness of direct roof,the elastic modulus of top coal and the elastic modulus of direct roof on the stability of top coal in the filling area along the roadway in the fully-mechanized roadway are studied by numerical simulation.The top coal control schemes of high strength anchor cable support and roadway side backfill support roof coal are proposed.(3)through numerical simulation analysis,it can be seen that when the width of the backfill is more than 2.5m and the strength is greater than 7MPa,the amount of roof subsidence decreases not significantly and the filling cost increases.When the roadway width is 3m,the surrounding rock deformation is the smallest,but it cannot meet the normal production needs.The control effect of no coal discharge over 6m surrounding rocks at the end is no longer obvious,which will also cause the waste of coal resources.According to the actual situation of the working face,the roadway retention scheme was selected as the side fill with a width of 2.5m,a strength of 7MPa,a width of 4m and a length of 6m without coal at the end.(4)based on the different ratio of the filling material on slump test and mechanical performance test,determine the different age paste specimen strength change of main influence factors,and according to the practical geological conditions of 42106 working face,and selected the optimum formula of the filling material on for cement,fly ash,coal gangue aggregate=1:2:5,slurry concentration is 78%,early strength agent adding amount is 1.6%of the overall quality.(5)combined with green hills,ping coal mine geological conditions and production technology,the research achievements of this paper was applied to 42106 fully-mechanized face along the empty left lane,impact on the working face mining along the empty left lane during monitoring and analysis of the effect of surrounding rock control,monitoring results show that the deformation of roadway surrounding rock and filling body deformation are in reasonable range,the effect is good,for to verify the correctness and reliability of research results. |
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