Influence of in-situ stress redistribution on proportional radii of blasting-induced cracking zones in tunnel excavation

Based on the study on the forming mechanism of blasting-induced crack under blasting stress wave, by adopting the Mohr-Coulomb criterion and the maximum stress criterion, the influence of in-situ stress redistribution on the proportional radius of the blasting-induced cracking zone (PRBICZ) in deep-buried tunnel excavation was explored. Results indicate that the in-situ stress redistribution has great influence on the PRBICZ, and that the in-situ stress redistribution in the rock mass can decrease the radial PRBICZ. Under compression and shear failure, the PRBICZ can be decreased more than 20%; under tension failure, the PRBICZ can be decreased more than 10%. Compression and shear failure of the rock mass is more likely to occur along the soft structure plane under blasting stress wave. The in-situ stress redistribution can reduce the blasting-induced cracking zone.