Combined pressure relief technology of coal pillar slotting and roof blast cutting in gob-side roadway
There are problems such as high stress concentration,large deformation,and difficulty in support in the goaf under the hard roof.Taking the 21105 working face of Hulusu Coal Mine as the engineering background,the breaking law of the overlying roof during the mining period of the working face under the hard roof was analyzed,the deformation mechanism of the surrounding rock of the goaf was studied,and a joint pressure relief roadway deformation control method of"roof blast cutting+ coal pillar ultra-high pressure hydraulic slotting"was proposed for the gob-side roadway.The stress distribution law of the surrounding rock of the goaf roadway before and after pressure relief was simulated using FLAC3D software.After adopting the combined pressure relief measures in the 21105 working face air return way,the peak stress at the deep base point of the gob-side coal pillar decreased by 36.1%,and the peak stress at the shallow base point decreased by 19.1%.The daily average energy of microseisms in the experimental area decreased by 67.0%,and the total energy of daily microseisms decreased by 35.7%.After adopting the pressure relief measures,the roof-to-floor convergence of gob-side roadway decreased by 60.1%,and the side-wall convergence decreased by 41.6%,the roadway deformation was effectively controlled.The experimental results show that,the combined pressure relief technology can effectively reduce the coal pillar stress,alleviate the roadway deformation,and provide a new deformation control method for gob-side roadway under hard roof.
hard roofgob-side roadwaydeformation controlhydraulic slottingroof blasting
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