Dynamic responses and damage mechanism of rock with discontinuity subjected to confining stresses and blasting loads.

• Dynamic finite element models were proposed to investigate the dynamic responses and damage mechanism of rock under blasting. • The propagation of blasting stress waves was analyzed together with the interaction of discontinuity orientation and confining stress magnitude. • The extension mechanism of the discontinuity was explored from the perspective of stress distribution and dynamic stress intensity factor (DSIF). • Rock discontinuity can weaken the crack-guiding effect of high confining stress, and high confining stress can suppress the development of radial cracks around borehole. The propagation of seismic waves induced by blasting changes significantly at rock discontinuities such as joints and faults, many studies have focused on the mechanism of wave propagation at joints. However, in deep rock masses, high in-situ stress is non-negligible, and the interaction between confining stress and discontinuity under blasting disturbance remains poorly understood. To explore the role of confining stress and discontinuity on the dynamic responses and damage mechanism of rock masses, this paper employed the dynamic finite element method and a series of numerical models were subsequently developed. The Riedel-Hiermaier-Thoma (RHT) model was used to simulate the blast-induced damage of rock. Under blasting disturbance, the propagation of stress waves and damage patterns within the rock at different discontinuity orientations and different confining stress magnitudes were presented. Around the discontinuity, the principal stress distribution and displacements were presented and the dynamic stress intensity factor (DSIF) of the discontinuity tip was obtained to analyze the extension mechanism of the discontinuity. Numerical results show that the discontinuity, the magnitude and direction of confining stress significantly contribute to the damage patterns of rock masses, and the guiding effect of high confining stress on cracking will be weakened due to the existence of discontinuity. [ABSTRACT FROM AUTHOR]