Stability Control Technology for Surrounding Rock During Vertical Shaft Construction Process in Deep Coal Mines

The deep vertical shaft of Changcheng No. 2 Mine is impacted by high ground stress, mudstone creep, and hydrothermal coupling, which makes the surrounding rock prone to instability and difficult to control with the traditional support. Based on rock mass mechanics and multi-field coupling theory, FLAC^3D numerical simulation is adopted to analyze the stress distribution, plastic zone evolution, and deformation laws of the surrounding rock of the wellbore. The results indicate that the asymmetric stress concentration around the wellbore is significant, the maximum thickness of the plastic zone is 6.1 m and radial convergence under the traditional support is about 58.7 mm. Thus, a three-level support system of "zoning control-active bearing-multi-layer coordination" is constructed to optimize the collaborative bearing mechanism between shallow anchor rods, middle anchor cables, and deep lining. The on-site applications show that the radial convergence of the wellbore is controlled within 35 mm, and the prestress loss of anchor cables is <10%, effectively improving the support stability. This research provides a technical path and parameterization scheme for the stability control of surrounding rock in deep vertical shafts, which has guiding significance for the safe construction of deep resource development.