Numerical Simulation of Deformation and Failure Mechanism of Main Inclined Shaft in Yuxi Coal Mine, China

Disturbance stresses can cause deformation and damage to a tunnel’s rock, potentially threatening the mine’s safety. This paper investigates the effects of disturbance damage on the main inclined shaft due to the excavation of an electromechanical chamber in a deep inclined shaft at Yuxi Mine. Specifically, a numerical model was constructed using Midas GTX NX and Fast Lagrangian Analysis of Continua in Three Dimensions (FLAC3D) to match the actual engineering conditions, and to reveal the stresses and deformations in the surrounding rock of the main inclined shaft before and after the excavation of the main inclined shaft, the electromechanical chamber and the head chamber. The results revealed that the surrounding rock stress around the main inclined shaft is significantly influenced by excavation disturbance. The bottom bulge occurred due to the unstable vertical and shear stresses in the bottom coal bed moving into free space. After the excavation of the electromechanical chamber, the maximum displacement of the floor can be increased from 0.35468 m to 0.64301 m, nearly doubled, and a large area of surrounding rock deformation occurs in the inclined shaft falling roadway. Affected by excavation disturbance, the maximum deformation of floor can reach 1.06 m, with a wide fluctuation range. The main area of damage to the surrounding rock was identified, except for the main inclined shaft, which occurred near the intersection of the inclined shaft and the drop level location. This area is mainly affected by superimposed tensile stress damage, prone to large area floor heave and spalling. The research content is expected to provide certain theoretical support in taking measures to deal with the deformation and failure of the surrounding rock in a main inclined shaft.