Research on Influence of Different Factors on Coal Wall Instability During Mining Process of Working Faces

In order to explore the influence of different factors on coal wall instability during working face mining, taking the 11051 working face upper layer of Zhaogu No.1 Mine as the engineering background, the influences of mining height, coal seam internal friction angle, and anchor rod support on coal wall stability are analyzed through FLAC^3D simulation. The research shows that with the increase of mining height, the vertical stress concentration zone in front of the coal wall gradually shifts downwards and forwards, and the area expands, when the mining height increases from 3.5 m to 4 m, the failure degree of plastic zone significantly exacerbates, among them, the proportion of shear failure is significant increased. The tensile deformation amount of the upper part of the coal wall increases from 18.2 cm to 35.6 cm, and the risk of wall caving is increased; When the internal friction angle of the coal seam increases from 20° to 40°, the maximum value of vertical stress is improved from 80.0 MPa to 104.8 MPa, the concentration zone shifts upward, the range of plastic zone is reduced from 26 m to 6 m, the horizontal deformation amount of the coal wall is significantly reduced, and the stability is enhanced; The influence of anchor rod support on vertical stress is extremely small, but it can control the range of plastic zone within about 2 m in front of the coal wall. The maximum horizontal deformation is reduced by 239 mm, effectively reducing the risk of wall caving. After on-site application, the frequency of wall caving is reduced by over 50%, achieving the effect of effectively reducing the wall caving risk.