Analysis of the effects of blast-induced damage zone with attenuating disturbance factor on the ground support interaction

The rock mass properties are typically influenced by the excavation technique and the changes in the state of stress due to the rock excavation. The amount and extent of damage introduced in the rock mass depends on the excavation technique and practice quality. The influence of blasting in the rock mass near the tunnel periphery is far more significant due to the energy of waves and redistribution of stresses and the severity of the damage diminishes as the radial distance from the tunnel opening increases. Therefore, it is important to consider the effect of the damaged zone when analysing the stresses and deformations around a tunnel. This study aimed at providing a new numerical solution for the determination of the ground response (reaction) curve with the consideration of the non-uniform damage zone around the tunnel periphery. A deep circular tunnel subjected to hydrostatic stress condition and excavated in rock materials obeying the Hoek-Brown failure criterion is considered. A solution for the determination of stresses, strains, and deformations around the circular deep tunnel is presented in order to correctly assess the attenuation of damaged rock as the distance from the tunnel perimeter increases considering the loads applied to the supporting structure.