| Currently, coal resources has entered deep mining stage, unlike the situation shallow mining, deep coal mining increased dramatically due to stress, complex geological conditions and other reasons, resulting in frequent occurrence of composite roof accidents.Kouzi east 11-2 coal mine area depth of 950 meters uphill pedestrian roadway above the rock due to geological deposits, there are many layered soft rock, typical of the composite roof. The deep mine intense pressure behavior for the effective control of 11 coal roadway stability, improve the supporting effect.The need for analysis and research of 11 coal roof rock structure and lithology, to determine the 11 coal distribution roof damage and the law of development of the location and value of the separation may occur.Based on the tunnel roof at different locations coring get different rock mechanics laboratory parameters, the roadway into a different roof positions such as coal, shale, sandstone, were established ANSYS FEM model calculation and analysis.Determining the difference between the value and the structure of the surface separation method to tensile stress values, to analyze changes in the value of roof separation, and roadway construction surface tensile stress distribution structure through displacement between adjacent surfaces. By changing the different conditions, such as the supporting force, roof lithology, roadway for lithology, two for roadway shape were simulated and analyzed on the roadway roof separation rule and the position of key stratum, the causes of roof movement law and separation. Video images based on the different position of the roadway borehole drilling, crushing of rock structural plane analysis, to verify the feasibility of the numerical simulation method.In this paper, according to the results of numerical simulation obtained the following conclusions:(1)Whether the roadway into the coal seam or seam roof, the key structural surface layer are different degrees of separation, the tensile stress in the structure plane is in the form of stress and arch in the numerical value, in the case of bolt anchor support, relatively wide range of tensile stress, there is a tendency for further separation of the roof;(2)The results of numerical calculation show that the different conditions, the normal tensile stress distribution of the structure surface is basically the same, the maximum tensile stress is in the range of 0.55 to 0.8 times of the width of the roadway;(3)The roadway bolt anchor supporting parameters affect the position of key stratum and interlayer separation stability, anchor cable pretension force to influence the separation layer is the most significant;(4)Roof layer composition on key positions and unstable trends, key roof layer mainly from the rock tunnel roof height, bed thickness and rock mechanical properties determined;(5)Compound roof weak interlayer although far away from the roadway, but poor stability, easy to produce separation is the weakest part of the roof, to strengthen support;(6)The structure of the surface layer of separation between the roof instability generated mainly from the critical level of development began, reasonable support(main anchor cable support) should focus on strengthening the key support level, the key to maintaining a stable layer;(7)Deep tunnel roof surface layer structure separated from the main key to the tensile stress caused by the structure of midface law should focus on strengthening the critical layer sandwich structure surface and weak central support, maintain stable interlayer separation. |
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