Deformation mechanism and rock burst prevention technology of service roadway under residual coal pillar

Abstract

In view of stress concentration, roadway deformation, rock burst and difficult support in the mining of the underlying coal seam under the residual coal pillar, we uses theoretical analysis and numerical simulation to analyze the stress distribution law of 8# and 9# coal seams and the stability of roadway under the disturbance of residual coal pillar in overlying 5# coal seam in a mine of Hebei. The research shows that the stress of the residual coal pillar after bearing the load presents the shape of “double peak”, “saddle”, “trapezoid” and “single peak” from the middle according to the width of the coal pillar. The stress concentration is higher in the irregular part of coal pillar, which has a great influence on the disturbance range of floor coal seam. The peak stress of the residual coal pillar is 52 MPa, and the stress transmitted to the underlying coal seam reaches 44 MPa, which is 2.2 times of the original stress. After the excavation of the service roadway, the stress is 37 MPa, which is 1.8 times of the original stress. Finally, the roadway under the residual coal pillar is controlled by strengthening support and relieving pressure of surrounding rock, so as to ensure the safety and stability of the service roadway.

Keywords

• residual coal pillar
• floor stress
• rock burst prevention technology
• disturbance effect
• numerical simulation