Phase field model of tunnel excavation damage zone

Excavation damage zone (EDZ) is an important index to evaluate the damage and failure of surrounding rock. Based on the rock phase field model considering rock nonlinear fracture criteria, the concept of excavation damage zone model is defined, the zoning criterion of excavation damage zone model is proposed. The topological region centered on the contour boundary of the tunnel is defined as damage phase field. The tunnel excavation damage zone based on the modified phase field model, and the inflection point of damage phase field gradient change is taken as the criterion of EDZ. By comparing and analyzing the site monitoring and numerical simulation results of Mine-by tunnel excavation damage zone at −420 m URL, the error is about 0.5%, which verifies the validity of the tunnel EDZ phase field model. The distribution characteristics of EDZ of tunnels with different section shapes are analyzed, the main damage characteristics and key reinforcement areas of tunnels with different shapes are expounded, and the rationality of phase field model of excavation damage zone is further explained.