Abstract
Blasting excavation of deep tunnels is a typical dynamic process subjected to in-situ stress redistribution and blast loading. This study establishes a numerical model for millisecond blasting in the DEM method for two-dimensional circular tunnel excavation. The process of millisecond blasting in a circular tunnel is depicted as a sequence of delayed multiple blastings (multiple dynamic loading-unloadings and static adjustment processes) executed on distinct blasting surfaces that are concentric with the tunnel. After calibration and verification, the dynamic stress evolution process of surrounding rock and the resulting damage to surrounding rock are investigated.
https://ror.org/00p4k0j84 
