Cracking formation and evolution in surrounding rock of a deep fractured rock mass roadway: A study of the 790-m level segment engineering at the Jinchuan Mine, China

Deep roadways within fractured rock mass present substantial challenges for mining and construction due to the risk of large deformations. This study focuses on investigating the formation and evolution of cracking zones in the surrounding rock, specifically analyzing the 790-m level segment within the Jinchuan Mine No. 2 Mining area. Our comprehensive approach integrates field investigations, laboratory tests, in-situ monitoring, and numerical simulations. The findings highlight the vulnerability of surface surrounding rock in the σ3 direction, leading to spalling and failure after excavation, while shallow surrounding rock acts as a natural barrier against deeper crack propagation. Over time, the elliptical cracking zone, aligned with the σ1 direction, expands, which progressively degrades the internal rock mass, ultimately resulting in support failure due to instability and increasing deformation pressures. To mitigate these challenges, strategies were proposed to minimize the initial cracking zone and halt its growth. The insights and guidance provided herein are invaluable for enhancing project safety and efficiency in designing and constructing roadways in similar geological settings. © 2024 Elsevier B.V.