Effect of intersection angle of structural planes on rockbursts under blasting-induced dynamic loads

This study investigates the influence of structural plane intersection angles on the rockburst behavior of deep tunnels under blasting-induced dynamic loads. A series of numerical simulations were conducted to reproduce impact-triggered rockburst events in pre-excavated caverns, considering five configurations of intersecting joints with inter-section angles of 0°, 45°, 90°, 135°, and 180°, respectively. To clarify the coupling mechanism between joint geometry, energy release behavior, stress redistribution, kinetic energy, and strain energy was analyzed. The results indicate that smaller intersection angles of structural planes lead to more concentrated blasting energy and a higher rockburst risk. Specifically, for angles ranging from 0° to 45°, the superposition effect of radial and tangential stresses is pronounced, accompanied by high kinetic energy peaks, dense fracture networks, and a high propensity for impact-induced damage. When the intersection angle increases to 135°–180°, the structural planes exert significant reflection and attenuation effects on stress waves, resulting in substantial reductions in the peak kinetic and strain energy of the surrounding rock and a lower degree of damage. Additionally, the evolution of the velocity field is closely correlated with fracture development: higher peak vibration velocities are associated with broader fracture propagation, whereas the formation of low-velocity, disordered zones indicate a tendency toward rock mass stabilization. These findings provide valuable insights into the dynamic response of jointed rock masses and offer theoretical support for optimizing blasting design and rockburst prevention in deep underground engineering.