Stress Analysis and Spalling Failure Simulation on Surrounding Rock of Deep Arch Tunnel

To study the stress distribution characteristics of surrounding rock and spalling mechanism deep hard tunnels with different arch heights, complex variable function angle-preserving transformation method in elasticity theory were applied to analytic solution tangential during adjustment. In addition, true triaxial tests conducted on granite cube specimens (100 mm × 100 mm) containing holes three heights (including 25 semi-circular arch, 16.7 three-centered 12.5 arch) simulate process under initial ground stresses. The experimental results show that failure is 0.39–0.48 times uniaxial compressive strength (UCS) rock. location occurs at foot, where maximizes. When lateral pressure coefficient range 0.38–0.50, 3.2–3.5 UCS. debris hole wall are thin flake shapes. Symmetrical V-shaped or curved zones occurred sidewalls. resolution shows increasing burial depth, bearing performance tunnel optimal. maximum increases as height decreases increases, making it easier for occur foot arch.