Study On Spalling Mechanism And Application Of Coal Wall With Large Mining Height

Large mining height technique is the important development directions of the thick coal seam mining process, with the increase of the mining height, the stability of working face coal wall decreased rapidly, the rib spalling of coal wall is seriously.The stability of large mining height influence safety and high efficiency production, the spalling mechanism of coal wall and evaluation of the stability are important research task of large mining height.This dissertation encircle the problem of the rib spalling of large mining height, analysis of the failure mode coal wall of large mining and the influence factors of the stability of coal wall. The production technology factors influence degree of working face coal wall is analyzed by the FLAC3D. The results is showed that, the maximum vertical displacement of coal wall take place in distance from the roof 0.5h-0.5 (h is mining height), the mining height and support strength are influence the stability of the coal wall of large mining larger; the coal wall of large mining height destroying forms from shear failure to tensile failure, the stability of working face coal wall decreased rapidly, because exists the superposition area of the shear failure and tensile failure. Four influence factors such as support strength, mining strength, mining height and side wall protection height are chosen on the basis of the analysis on the rib spalling of coal wall and the analysis on the numerical simulation. The stability factors changed from qualitative to quantitative by the semantic description, and the model of in large mining height long wall face is set up by the AHP. The evaluation model is used in 12011 working face in Henan zhaogu No.1 mine; the result of evaluation was basically identical with the result field measurement.The analysis on the coal wall stability of large mining height changed from qualitative to quantitative.by establishment of the model of stability evaluation. The application results show that the model has certain practical value and reference value for the stability evaluation of coal wall and explore a new method.