Research on the Floor Rockburst of Panel Entry under the Mining Influence: A Case Study

Abstract

AbstractThe stability of the entries of longwall panels is the key to ensure efficient and safe production of coal mines. In order to solve the common problems of floor heave of panel entry in western China, based on a case study, this paper studies the rockburst instability mechanism of entry floor-induced mining by considering the results from a laboratory test, numerical simulations, and field practice. After testing, the coal and rock of the entry are hard and brittle. In particular under the action of impact dynamic load, its dynamic strength is higher and has a positive correlation with the impact pressure, which provides a mechanical premise for subsequent rockburst. Numerical simulation results show that with the mining of the panel, the vertical stress and the maximum principal stress of the floor are mainly concentrated in the coal pillar along the entry, and the area and degree of concentration continue to increase. The horizontal stress is mainly concentrated in the entry floor, which is distributed in the advanced range of the panel. The deformation rate of the entry roof and the ribs is stable, while the floor shows a “mutation” characteristic of not deforming when the panel is far away and suddenly rising when it is closer to the panel. The range of the plastic zone of the roof and floor remains unchanged, the ribs are further deepened, and the mechanical properties of the coal and rock mass are further weakened. The results of this study contribute to providing a reference for the control of surrounding rock of panel entry under similar geological and geotechnical circumstances.