Abstract
Purpose. To investigate the stress-strain state of the coal-rock mass surrounding a gob-side development roadway and to justify its support parameters under the mining conditions of the Karaganda Coal Basin. Methods. The study was based on geomechanical modeling of the coal-rock mass surrounding a roadway driven adjacent to the goaf of a previously extracted longwall panel and separated from it by a limited-width coal pillar. The simulations were performed in ANSYS using the finite element method in 2D. The computational model incorporated the goaf, protective coal pillar, stratified structure of the surrounding rocks, mining depth, physical and mechanical rock properties, loading conditions, and roadway support parameters. The stress-strain state and strength factor were additionally assessed in Rocscience RS2 for a ventilation roadway driven along the boundary of the goaf. Findings. The width and strength of the coal pillar were found to affect stress redistribution around the gob-side roadway significantly. A limited-width pillar shifted the peak maximum stress 5-10 m deeper into the intact coal mass and reduced its magnitude by approximately 1.6 times compared with the pillarless configuration. Stresses directly above the roadway decreased by a factor of 1.2-1.3. Increasing the pillar strength or its width to 20 m reduced the maximum stresses in the rock mass by almost twofold. The RS2 simulations showed that increasing the mining depth from 450 to 700 m increased the maximum principal stresses by a factor of 1.7-1.9 and the roadway contour displacements by a factor of 1.2-1.35. Originality. Relationships governing stress redistribution and the formation of reduced-stability zones around gob-side development roadways were established as functions of coal pillar parameters, mining depth, and roadway support conditions. Practical implications. The results provide a geomechanical basis for selecting support schemes for gob-side roadways located within zones of elevated rock pressure.