Abstract:In order to study the evolution of the collapse range of surrounding rock during tunnel excavation and reduce the adverse impact of collapse on tunnel engineering, this paper explores the damage pattern of top surrounding rock during tunnel excavation under the nonlinear Mohr-Coulomb strength criterion combined with the limit analysis upper limit theorem, constructs the collapse mechanism of deeply buried tunnel in three-dimensional state, and studies the evolution of tunnel collapse range based on deterministic analysis and probabilistic analysis, respectively. The evolution of tunnel collapse range is studied based on deterministic and probabilistic analysis. The results show that: the tunnel collapse radius and collapse height are positively correlated with the axial tensile strength, and negatively correlated with the weight and pore water pressure coefficient, while the tunnel collapse radius increases and the collapse height decreases with the increase of the initial cohesion; by comparing the collapse range under 68% and 95% probability conditions, the collapse radius and collapse height increase with the increase of the nonlinear coefficient, and the shape of the collapse body gradually changes from cone to cylinder. It can be seen that there is a correlation between tunnel collapse and geotechnical parameters, and the results of the study can provide a reference for tunnel disaster prevention and control.