Abstract:
In order to study the influence of different mining-caving ratios on the stability of stope under fully-mechanized caving mining technology, the stress of top coal was studied by theoretical analysis and numerical simulation. Based on the theory of elastic foundation beam, the loading mechanism of top coal before caving was analyzed, and the loading condition and deflection analytical solution of top coal after coal mining were obtained. The numerical models of different mining-caving ratios were established, and the stress, displacement distribution and plastic zone distribution characteristics of fully-mechanized caving stope before and after caving under different mining-caving ratios were analyzed. The results show that the deflection of the working face is related to the width of the working face, the height of the coal mining and the load of the overlying rock before the coal caving after the coal mining. When the thickness of the coal seam is 4.5 m, the deflection of the working face can reach 1.55 m, which is similar to the numerical simulation results. With the increase of the proportion of coal mining thickness in coal seam mining, the stress concentration, displacement and plastic zone before coal caving increase slightly, but there is no significant change trend in the stope after coal caving. The low roof of the stope is mainly tensile failure, and the high roof is mainly shear failure. When the mining height accounts for a large proportion, it is more conducive to the caving of top coal.