Investigation on the influence of intersecting structural planes and their positions on rockburst in deep tunnels under blasting loads

Abstract

Rockburst frequently occurs in deep underground engineering and is strongly influenced by structural planes in surrounding rock. To investigate the role of intersecting structural planes in tunnel rockburst under blasting disturbance, numerical simulations were conducted using the discrete element method in PFC2D. Different in situ stress levels (25–55 MPa) and structural plane intersection angles (30°–150°) were considered to analyze the evolution of tunnel failure patterns, radial stress, kinetic energy of ejected rock blocks, and strain energy of surrounding rock. Weak interlayers were incorporated into the PFC2D model to represent the weakened mechanical characteristics of structural planes in fractured rock masses. The results show that the position of structural planes significantly affects the intensity and location of tunnel rockburst. When structural planes are located on the right side of the tunnel, the surrounding rock directly bears blasting-induced stress waves, resulting in higher radial stress, greater kinetic energy release, and more severe rockburst damage. Under high in situ stress conditions, structural planes become dominant weak zones that promote stress concentration and large-scale structurally controlled rockbursts. These findings improve the understanding of energy evolution mechanisms of rockburst in jointed rock masses and provide guidance for rockburst prediction and prevention in deep tunnel engineering.