Deformation Law of Fractured Rock Mass in Coal Seam Roof under Repeated Mining
In order to understand the impact of repeated mining on the roof cracks of the overlying strata in 48703 working face of Ximing Coal Mine,FLAC3D numerical simulation software was used to simulate and analyze the repeated mining process of 48703 working face.As the coal seam mining progresses,the stress at the cut and front of the coal wall shows an increasing trend,while the rock mass in the upper part of the goaf is the opposite.The roof rock mass of the coal seam undergoes downward displacement in the vertical direction due to the redistribution of geostress,and the maximum displacement of the upper rock mass at the drilling position reaches 11.6 mm.After excavating 50 m,the stress simulation image shows a saddle shape with a low center and high ends.Overall,the deformation and failure of the roadway roof under repeated mining depend on the spatial distribution of the roof and floor crack zones.
repeated miningroof cracksnumerical simulationdeformation law
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