Numerical Calculation and Stability of the Yield and Enhanced Support Technology for Shaft

This work study the auxiliary shaft in Jinchuan No. 3 mining area. A numerical calculation method is adopted in this study to optimize retention space to yield for the support of the shaft and to analyze the stability of the surrounding rock mass to solve the large deformation problem occurring in shaft excavation. Firstly, three different sections are investigated, including the shaft wellhead section, main body and cross-cut under the shaft. Support and reinforcement solutions based on the retention space to yield support technology of shaft are proposed twice to resolve the corresponding problems appearing during construction. The relationship between the thickness of the lining and the convergence of the lining, the thickness of the plastic zone and the maximum principal stress of the lining is then identified through a planar model analysis on the shaft cross-section with the depth of 250 m, 400 m, 500 m, and 650 m. Lastly, a three-dimensional numerical simulation and safety evaluation of the first support design (50 mm bolt–shotcrete mesh + 450 mm plain concrete), as well as a stability analysis on the adjusted support solution (50 mm bolt–shotcrete mesh + 750 mm plain concrete) for a stratum of poor conditions are carried out using software FLAC^3D.