Experimental and numerical study on the influence of blast loading on the stability of steeply inclined stope

Abstract

During the blasting process in underground mine stopes, the stability of deep stopes is a prerequisite for safe mining operations. In this study, a high-stress and blast vibration coupling physical similarity test model was developed. Stress sensors, static strain sensors, and dynamic strain sensors were employed to investigate the influence of high in situ stress and blast-induced vibration on stope stability. Furthermore, a continuum-discrete coupling numerical model was constructed to explore the microscopic mechanical behavior and damage effects of blast vibrations on the stope. The results indicate that the self-designed blasting source test method and particle vibration loading simulation method effectively replicate the blasting process within the stope. During blasting-induced mining, the roof and hanging wall of the stope first experience compressive stress, followed by tensile stress, with a peak deformation reaching (including the horizontal deformation of the hanging wall and the vertical deformation of the roof) up to 150 με. As the horizontal distance from the stope increases, the vertical stress distribution in the hanging wall exhibits a “low-high-low” pattern, with the stress concentration region located approximately 4 cm from the stope. Numerical simulations further revealed that the blasting-induced vibration effect significantly increased the deformation of the surrounding rock, leading to a denser distribution of microcracks. The maximum depths of microcracks reached 1.8 cm in the roof and 2.2 cm in the footwall. Although the vibration induced an instantaneous large deformation, the overall integrity of the surrounding rock remained well preserved. Therefore, the impact of blasting disturbances on the stability of the stope roof and the hanging and footwalls is considered to be within a controllable range The proposed research methods and findings provide a theoretical basis and technical support for optimizing blasting parameters and ensuring the safety of deep mine blasting through experimental and numerical analysis.