Effects of the borehole drainage for roof aquifer on local stress in underground mining
Geomechanics and Engineering, 24(5):479 - 490, 2021.
Summary
Draining groundwater through boreholes can reduce the danger of water entering an underground coal mine, but it also changes stresses in the surrounding strata. This study examines that interaction using theoretical analysis and numerical simulations informed by drainage above the 1303 mining face at Longyun Coal Mine. As water levels fall, three stress regions develop outward from a borehole: a relaxed inner region, an elevated-stress region, and an outer region where stresses recover toward their original state. The peak stress moves outward as the drainage influence expands, then stabilizes when that influence reaches its maximum extent. An advancing mining face can bring its abutment pressure into the same area, increasing stress concentration through superposition. The results identify a mechanical consequence of groundwater control that should be considered when planning the arrangement of drainage boreholes.