Fracture evolution and fracture mechanism of tunnel surrounding rock: A case study based on laboratory tests and theoretical analysis

To explore the fracture characteristics and fracture mechanism of the surrounding rock of straight-walled arched tunnels, this study first carried out biaxial compression tests on rock samples and analyzed the disaster evolution characteristics under loading. Then, a stress distribution function was established using a complex function, and the distribution characteristics of the surrounding rock stress field were determined. Finally, combining the stress field with results obtained by computational tomography and acoustic emission measurements, the dynamic evolution of the main fracture mechanism of the tunnel surrounding rock was comprehensively analyzed, and the fracture mechanism of the surrounding rock of the straight-walled arched tunnel was elucidated. The research results strengthen the understanding of rock fracture evolution during tunnel construction and operation and provide a basis for tunnel construction and surrounding rock stability analysis.