Stress distribution and roadway layout under narrow coal pillars in close coal seam group

Abstract

Aiming at the stress distribution and roadway layout problems under the narrow coal pillars in close distance coal seam group, theoretical analysis, numerical simulation and field measurement are used to analyze the stress distribution characteristics of the coal strata under the narrow coal pillars. Studies have shown that, affected by the sequential mining of adjacent working faces, the overlying rock layer of the coal pillar revolves toward the back of the working face, which causes the peak support stress to shift to the side of the back mining face, and the supporting stress of the coal pillars is distributed asymmetrically; affected by the supporting stress, the stress distribution of the coal strata under the coal pillar shows asymmetry corresponding to the supporting stress, and the degree of asymmetry increases with the decrease of the coal pillar width. Combined with actual engineering cases, according to the distribution of the vertical stress and principal stress difference of the lower coal seam floor, and taking into account the influence of the asymmetric distribution of stress, the location of the mining roadway in the lower coal seam is finally determined.

Keywords

• close coal seam group
• narrow coal pillar
• stress distribution
• numerical simulation
• roadway layout