| Based on the study of the deep close distance medium-thickness coal seams in thethree level, No.1coal mine, Pingdingshan Coal Mining Group, the stress distributionlaw, the structure characteristics of overburden and strata pressure behavior law of thedeep close distance coal seams is discussed and a primary and exploratory study aboutrational position and supporting pattern of mining roadway by using theoretical analysis,field measurement, numerical simulation and industrial test is accomplished.The injury failure depth of roof in deep close distance lower coal seam by using thetheory of elastic-plastic and slip line is derived. Combining with strata pressure law,overburden is regarded as block-granular structure. It’s boundary condition is the upperof mining face. Stability Analysis for roof rock structure of lower coal seam by usingblock-granular structure as a model is completed. The mechanism of roof caving in thedeep close distance lower coal seam is described, which provides a theoretical basis fordesign of support load and surroundings rock control in lower coal face. The stratapressure behavior law of the E8-31080and E9-10-31040working face is obtained in thedeep close distance lower coal seams. Using the elastic-plastic finite element softwarePhase2of nonlinear two-dimensional, the law of stress distribution of the surroundingrock in close distance coal seams is simulated. According to mining roadway ofE9-10-31040working face, the law of non-uniform stress distribution of the floorcoal-rock under pillar load in the deep close distance upper coal seam is studied. Thecause of local overload and the final instability in support structure is revealed.Combining with above results, the rational position of mining roadway in the deep closedistance lower coal seam is explored. The plastic pillar width of E8coal seam iscalculated, meanwhile, combined support system with truss bolt has achieved goodeffect in industrial test. |
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