Perpustakaan Digital ITB

Because gas boreholes are easy to damage by integrated coal mining and gas exploration, based on the practice of relieving pressure in deep thin coal seams in the Huainan mining area, a multidimensional coupling numerical simulation method was used to reveal the space-time evolution characteristics and influence factors of fracture deformation of gob-side gas boreholes. Results indicate that the danger zone for borehole fractures is primarily between 5 and 12m above the roof of the roadway. +e final-hole position has little effect on the stability of boreholes, and migrating the open-hole position to the entity coal side and roadway roof side can improve the stability of the borehole. +e initial failure of the borehole occurs at a distance of 10m behind the coal face. +e failure of the borehole is largely stable at a distance of 100 to 120m behind the coal face. With the increase in mining height, which leads to an increase in the movement of strata and an increase in pressure relief range, the shear stability of the borehole is reduced, and the extrusion stability of the borehole is improved. A hard roof condition promotes borehole shear stability, while a weak roof condition promotes borehole extrusion stability. +is change can decrease the maintenance difficulty associated with “minor supports” in boreholes to a certain extent by reinforcing the support strength of “primary supports” in roadway retaining walls. +e simulation results are consistent with observed results for the 11 test boreholes, and the accuracy of the numerical simulation is verified.