Analyzing the Deformation and Damage Characteristics of Roadway Perimeter Rock and Support Optimization in Yongchang Lead-Zinc Mine

Herein, the 200 m middle section of the largest roadway in Pit 860 of the Mengnuo mining area, situated in the Yongchang Lead-Zinc Mine in Baoshan, Yunnan Province, was utilized as the research object. The researchers conducted an on-site investigation of the surrounding rock deformation and damage and the current state of support and utilized a three-dimensional finite-difference numerical simulation software, FLAC3D, to simulate the inversion of the roadway's surrounding rock deformation characteristics after excavation (i.e., the original use of the support method), the instability characteristics of the surrounding rock under the original support, and the support provided by the anchor spraying network. Based on the original support method, four optimized support schemes are proposed to address the asymmetric deformation of the surrounding rock and the apparent bottom bulge of the roadway: (1) anchor spraying net (long and short anchors + locking foot anchors), (2) anchor spraying net + concrete bottom beam, (3) anchor spraying net + unloading groove, and (4) anchor spraying net + antibottom arch. The study compares and analyzes the effect of the different schemes in controlling the surrounding rock, and the results indicate the following: Scheme 4, which entails excavating the antibottom arch at the bottom of the roadway, is the most optimal solution for controlling the surrounding rock in the various areas of the roadway. The results confirm that Scheme 4 exerts the most optimal effect. The final optimized support scheme for the railway is determined, providing reference significance for the deep mining domain and similar geological conditions.