<p>Spalling failure is a prevalent form of tunnel damage and is pertinent to the safe operation of mines. The present study investigates the influence of excavation and impact conditions on the spalling failure of tunnel surrounding rock, utilizing a self-developed continuum-discontinuum method. This method incorporates a node separation technique and a fictitious crack model which is employed to simulate the progressive cracking process. In this study, five schemes with different initial stresses and impact loads were designed. Under the boundary conditions delineated in this study, the degree of cracking caused by the excavation unloading in the vicinity of the tunnel roof, floor, and side walls shows little variation, but the impact-induced cracking of the upper side of the tunnel demonstrates the most severe, attributable to the reflected impact waves generated by the tunnel roof. During the excavation stage, high in-situ stress intensifies the excavation unloading effect. The combined influence of gravity and excavation unloading causes more severe cracking in the tunnel roof, while suppressing cracking in the tunnel floor. During the impact stage, when the initial stress remains constant, the impact-induced cracking zone is observed to be larger and cracking becomes more complicated with an increase of the impact load. Lower in-situ stress results in less elastic strain energy stored in the surrounding rock, thereby diminishing its resistance capacity and triggering more severe fracturing. The tunnel structure obstructs the propagation of impact stress waves, thereby reducing the influence of impact load on the tunnel floor. The side of the tunnel facing away from the impact source experiences reduced impact disturbance, though this is not entirely eliminated. The research findings provide a theoretical foundation for preventing and controlling spalling failure of surrounding rock in deep tunnels.</p>