Mechanism of rock burst in deep double pillar roadway

Abstract

According to the characteristics of deep double coal pillar working face in Hongqinghe Coal Mine, such as strong rock burst, large damage range and complex influencing factors, the methods of surface observation, coal stress monitoring and micro-seismic monitoring were used to analyze the buried depth, double width coal pillar reservation and mining influence that affect static load, as well as the structure of thick roof strata that affects dynamic load and the adjacent goaf with insufficient caving. In this paper, the evolution process of static load and dynamic load of rock burst was studied, and the mechanism of rock burst was revealed. The research showed that the new auxiliary static load of 3-1103 caused by deep double coal pillar consists of foundation load, mining stress and lateral stress of coal pillars. The superimposed static load reached 1.4-4.5 times of the vertical stress, and the static load reaches 24.9-80.1 MPa, which is close to or exceeds the critical load of rock burst of coal seam. The rock structure above the coal pillars was damaged to the depth of the coal pillars, releasing the bending and sinking process. The accumulated elastic energy caused the stress of the coal pillar to rise, and the stress of the coal and rock mass transferred to the deep part. The failure position was closer and closer to the 3-1103 working face, thus inducing the instability of the coal and rock mass with high stress concentration.

Keywords

• deep double pillar roadway
• rockburst
• dynamic and static load
• surrounding rock activity
• occurrence mechanism