Abstract: Blasting excavation disturbance is an important influence factor to the inoculation and evolution of deep tunnel damaged zone. According to the drilling and blasting excavation process of the tunnel, the disturbance effects induced by blast load and transient unloading of excavation load are analyzed; and based on the LS-DYNA dynamic finite element program, the numerical simulation method of blasting excavation disturbance is proposed that using nodes reaction to simulate the constraint of the awaiting excavation tunnel rock, controlling the change process of nodes reaction to simulate transient unloading of excavation load, and using blasting loading change curve to simulate the effect of explosion. After that, the blasting excavation induced damage of tunnel rock mass is analyzed by the method. The results show that the surrounding rock damage zone is mainly caused by the in-situ stress redistribution and increased by blasting load; the surrounding rock damage zone is maximum when the transient unloading of excavation load is taken into account; and in-situ stress is higher, the damage caused by transient unloading of excavation load is more remarkable

Key words: tunnel, blasting, damage, transient unloading, numerical simulation