Experimental study on the external damage characteristics of rock blasting under confining pressure

Geostress has a significant impact on rock blasting performance. To investigate the external destruction features of rock blasting under geostress conditions, cement mortar specimens were employed as analog rock materials. Model experiments and numerical simulations of rock blasting were performed under different principal stress magnitudes and directions. This study focused on analyzing the fragmentation volume, fragmentation, crack quantity, and damage extent of rock blasting under in situ stress conditions and quantitatively assessed the damage parameters of geostress on the external effects of blasting. Numerical simulations were used simultaneously to validate the experimental results. Numerical simulation analyses of damage in trench blasting under different in situ stress directions revealed the following: (1) When the principal stress direction is fixed, as the principal stress value enlarges, the number of cracks decreases, and the blasting damage area and fragmentation volume also decrease; (2) when the equivalent load magnitude is constant, the blast damage area and destruction volume change little, but changes in the equivalent load direction cause blast cracks to shift and also guide the direction of blast damage; and (3) for complex deep environments, optimizing blast schemes by considering in situ stress direction can effectively enhance blast performance, providing a reference value for deep blast engineering.