Study on stress change law of coal body permeability improvement by mechanical reaming

Mechanical reaming, as a new type of coal seam pressure relief and permeability enhancement measure, can be widely applied to low permeability gas coal seams. In order to investigate the stress evolution law of mechanical reaming, the stress distribution characteristics of mechanical reaming were revealed through theoretical analysis; taking 2616 coal seam of Juji Coal Mine as the research background, the stress evolution law of coal seam during the reaming process was analyzed by ABAQUS numerical simulation software. The results show that: there is a dynamic evolution of the stress field of the coal body around the hole after mechanical reaming, which is distributed in a circular pattern from inside to outside, in the order of fracture zone, plastic zone, elastic zone and original stress zone; the stress disturbance range and stress concentration in the hole-making stage during mechanical reaming are significantly larger than those in the drilling stage.