Investigating the factors influencing vertical stress ahead of the undercutting line in block caving

In block caving mines, stress evolution induced by undercutting poses a significant threat to the integrity of extraction structures. Focusing on the Pulang Copper Mine, this research analyzes the controlling factors behind the vertical stress concentration ahead of the undercutting line. Numerical and field data revealed that the undercutting span, burial depth, and internal friction angle of the rock mass were the dominant influencing factors. Specifically, vertical stress intensifies with larger spans and greater depths. Conversely, the extent of the failure zone ahead of the face increases with burial depth but decreases with a higher internal friction angle. This study provides both a mechanistic understanding and a practical basis for optimizing undercutting parameters under similar conditions.