Physical model test and numerical simulation study of cumulative damage to deep tunnel surrounding rock under cyclic blasting load

Cyclic blasting excavation of a deep tunnel frequently disturbs the surrounding rock, and cumulative damage effect will occur in cases multiple blasts are applied. To study the damage evolution trend of tunnel surrounding rock under multiple cyclic blasting load, a self-made physical model test system was used to test cyclic blasting excavation of a tunnel under high in-situ stress. Meanwhile, according to the characteristic that the damage of rock under frequent disturbance will appear cumulative superposition, an improved Bingham creep damage constitutive model was established. The constitutive model was applied to the numerical simulation of tunnel cyclic blasting excavation, and the numerical simulation reproduced the physical model test to study the rock damage evolution laws. The results from the physical model test and the numerical simulation revealed that the process of damage evolution of rock in in-situ stress state under the impact of multiple blasting disturbances had a non-linear cumulative characteristic. In addition, the results also shed light on the relationship between the damage zone expansion and the number of cyclic blast. This paper can provide a reference for studies of the damage evolution in deep rock under blasting impact.