Meikuang Anquan (Jul 2023)
Research on law of shock bump activity in irregular face and control of inducing rock burst risk
Abstract
Aiming at the problem of frequent shock bump during the mining of irregular faces, this paper takes 21306 working face of a mine in Shaanxi as the engineering background and adopts methods such as theoretical analysis, numerical simulation and field practice. The fracture characteristics of the overlying strata on the 21306 working face and the stress distribution characteristics of the surrounding rock during mining are analyzed, the law of mining shock bump activity at irregular faces is studied, and the risk control plan for shock bump induced by reducing load and releasing energy is optimized. Research indicates: the 35 m section coal pillar can restrict the coordinated movement of the overlying strata of the two working faces. During the mining of the 21306 working face, the overlying strata structure is an “O-X” fractured structure, forming a symmetrical long-armT-shaped structure with the adjacent goaf; during the mining period of the working face, the leading area of the working face advancement process and the influence range of the stress on the side of the transportation roadway continue to expand, and the stress concentration in the section coal pillar area is the largest. The vertical stress reaches the maximum at 480 m, which has reached 54.67 MPa, which is about 1.41 times the vertical stress before the mining; as the working face advances to form a “knife-shaped” irregular structure, the stress concentration in the corner area of the working face is significantly higher, and the impact of the working face on the transportation roadway is reduced after the working face is reduced; during the mining of the working face, the shock bump source events are mainly distributed in front of the mining work, and the strong shock bump are mainly concentrated in the mining shrinkage area and square area of the working face, strong shock bump mainly occur within the range of 50 m in front of the work face and 22-74 m above the floor. The source of strong shock bump induced force is mainly caused by the breakage of key layers in some areas; the optimization scheme of mine shock risk control with load reduction and energy release is implemented, which effectively reduces the occurrence frequency of strong shock bump and guarantees the safety of late mining of the working face.
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