Research on the stability evaluation of the through shaft between the return airway and the air shaft

In order to explore the wellbore stability in the process of roadway penetration, based on the -290 return air roadway (north section) of Nantun Coal Mine penetrating Baimahe wind well, the mechanical properties of the penetration stratum and overlying strata were obtained through indoor mechanical tests. The displacement, stress and strain changes in different directions of the wellbore after penetration and the roadway support effect in the penetration area were simulated by ANSYS numerical simulation software, and the wellbore stability was analyzed by displacement method. The research results indicate that the conglomerate at the junction is of medium to high strength, the mudstone is of medium strength, and the overlying sandstone is of high strength. There is a risk of plastic failure on the east side of the inner edge of the wellbore through the area, while the west, north, and south sides of the inner edge of the wellbore are stable. The use of anchor mesh+U-shaped steel beam composite support in the through area has a significant effect. The research results provide good reference value for the stability evaluation of coal mine shafts and tunnels.