Real-Time AE − DIC Analysis and DEM Modeling of Structure-Controlled Rockburst Evolution in Hard Rock Tunnels

Structure-controlled rockbursts frequently occur in deep hard-rock tunnels and pose a serious hazard to construction safety. To elucidate the governing mechanisms, we conducted physical model tests using a self-developed deep hard-rock analog material and performed real-time characterization of multi-scale mechanical responses via coupled acoustic emission–digital image correlation (AE–DIC). We further implemented, through the FISH scripting language, discrete element method (DEM) procedures for stereographic projection of principal-stress orientations, together with numerical evaluation of the local energy release rate (LERR) and the failure approaching index (FAI), enabling an integrated experimental–numerical analysis. Across structural-plane configurations, we observe pronounced strain-field localization, redistribution of principal-stress orientations, spatiotemporal crack-opening evolution, energy dissipation, and macro–micro damage accumulation, accompanied by quantitative assessment of rockburst intensity and formation processes. A tension–shear-coupled concentration of principal-stress difference develops near structural planes, producing strong localization in both the strain field and LERR. Structural-plane geometry significantly influences the spatiotemporal distribution and opening amplitude of cracks. Frequency-domain analysis of AE waveforms using the fast Fourier transform (FFT) yields amplitude and dominant-frequency indicators, which capture the transition from microcrack initiation to macroscopic failure and the associated failure modes of structure-controlled rockbursts. Spatial patterns of FAI indicate that structural planes can both initiate rockbursts and act as boundaries that constrain their further propagation. Using AE amplitude and energy, strain energy, and the strain-energy attenuation coefficient, we quantify the triggering criteria, rockburst intensity, and the energy-damping effect of structural planes. DEM-based stereographic projection captures the reorientation of principal stresses (azimuth and plunge) within crack-initiation zones at structural-plane tips. Interchange of \ (₂\) and \ (₃\), horizontalization of \ (₃\), and a sustained increase in principal-stress difference jointly induce incompatible deformation, constrain the rupture-path orientation, and ultimately trigger structure-controlled rockbursts. These findings provide a theoretical basis for predicting and mitigating structure-controlled rockburst hazards in deep underground engineering.