Mechanism and Prevention of Rock Burst Induced by Multi-key Layer Fracture of High Stress Coal Pillar

Aiming at the technical problem of preventing and controlling the large section coal pillar rock burst of high-strength mining under the control condition of overlying multi-key strata, the mechanism and prevention and control methods of coal pillar rock burst in the return air roadway section of 31102 working face of a mine were studied by means of numerical simulation, key strata analysis and micro seismic monitoring. The results show that the maximum stress concentration factor of coal pillar is 3.02 under the action of high static stress in the return air roadway section; there are many key strata above the working face, and a large number of micro seismic events occur when the key strata break, and act on the coal pillar in the form of additional dynamic stress. When the sum of forces is greater than the strength of the coal pillar, the coal pillar will be impacted. The preventive measures of “pre-pressure relief of large diameter boreholes + on-site pressure relief of secondary oblique boreholes” are proposed. The field measured data show that the scheme is effective and reliable.