Numerical Simulation Study and Engineering Validation based on Coal Seam Roadway Excavation

In order to effectively prevent and control the gas disaster during the mining of deep coal rock bodies and improve the extraction efficiency, this paper carries out the research on the coal microstructure, gas seepage and the characteristic parameters of the coal rock bodies by means of scanning electron microscopy and low-temperature liquid nitrogen adsorption test, and adopts a combination of numerical simulation and on-site engineering validation to study the stress distribution around the surrounding rock after excavation, the range of fracture zone and plastic zone generated by the coal rock around the drill hole to optimise the design parameters of gas extraction in the mining area, by using FLAC 3D and COMSOL Multiphysics. The stress distribution around the surrounding rock after excavation, and the range of fracture and plasticity zones generated in the coal rock around the drill holes, in order to optimise the design parameters of gas extraction in the mine. The study shows that: with the increasing of lateral pressure coefficient, the stress concentration phenomenon in the roadway evolves into vertical symmetrical distribution, the working face of the test mine coal seam crushing area ranges from 0 to 5m, the coal seam plastic area ranges from 12 to 16 m, the stress concentration area ranges from 8 to 24 m, and the original stress area is after 24 m, and the depth of drilling hole reaches the peak of the stress at 16 m, and the drill cuttings method is adopted on the site to verify the simulation results, and then it is decided to determine the reasonable sealing depth of 2#coal seam in the test mine. After verifying the simulation results by drilling chip volume method on site, it is determined that the reasonable sealing depth of the test mine 2# seam is 16 m.