## 5 Conclusions  
This study employed a true triaxial loading system and advanced monitoring tools to simulate and analyze a strain-mode rockburst in granite, exploring its evolution process, failure mechanisms, and monitoring approaches. The rockburst evolves through five stages, from stress accumulation to residual stress adjustment, marked by dynamic responses and energy release. Failure is characterized by a tension-shear coexistence mechanism, forming V-shaped craters through crack propagation and composite failure near free surfaces. Acoustic emission monitoring proved effective in identifying rockburst precursors, with AE signal patterns providing critical indicators for early warning systems. These findings enhance the understanding of strain-mode rockburst mechanisms and offer practical insights for deep rock engineering safety. The principal conclusions are as follows:  
1. **Experimental Method and Evolution Process of Strain-mode Rockburst. ** A true triaxial loading system was employed to simulate strain-mode rockbursts using granite samples due to their high compressive strength, elastic modulus, and uniform structure. This system replicates deep underground stress conditions, enabling precise analysis of directional splitting and failure. Advanced monitoring tools, including acoustic emission and high-speed imaging, ensured comprehensive observation of crack evolution and energy release during rockburst simulations. The evolution of strain-mode rockbursts progresses through five distinct stages: stress accumulation, crack initiation, critical instability, rockburst occurrence, and residual stress adjust  
Figure 6: The AE amplitude-frequency distribution (left) and AE counts–\(b\) value relationship (right). (**a**) The granite specimen AG2. (**b**) The granite specimen AG3. ment. Each stage exhibits increasingly intense dynamic responses, culminating in violent energy release and rock ejections. The transition from elastic deformation to dynamic failure highlights the critical role of crack propagation, stress concentration, and subsequent stress readjustment in the rockburst mechanism. This staged classification has been validated not only in laboratory settings but has also been consistently corroborated by numerous field cases [33; 34; 35], thereby underscoring the complexity and diversity of the strain-mode rockburst process. 2. **Failure Modes, Mechanisms, and Acoustic Emission Characteristics. ** The failure modes of strain-mode rockbursts in granite exhibit a tension-shear coexistence mechanism, driven by the interaction of vertical splitting cracks and diagonal shear fractures. Shear-tension composite failure near the free surface leads to violent rock fragment ejections, forming V-shaped rockburst craters. These craters reflect the brittle behavior of rocks under high-stress conditions and dynamic energy release, providing critical insights into the mechanics of failure in extreme stress environments. Furthermore, the AE signals were found to be highly effective for monitoring rock mass failure, with their activity effectively indicating rockburst stages. Low and sparse AE counts during a quiet period signal potential precursors, while a sudden surge in AE counts, coupled with a \"V-shaped\" trough in the AE b-value, serves as a critical indicator of an impending strain-mode rockburst. These observations underscore the significant potential of AE monitoring as a reliable and practical tool for developing early warning systems in rock engineering applications. Furthermore, the existing literature indicates that the strength of granite decreases under saturated conditions, which increases the likelihood of rockbursts [11; 36]. In our future research, we intend to develop multiphysics coupling models to accurately simulate the behavior of strain-mode rockbursts influenced by water. Conceptualization, Z.M. and F.M. ; writing--original draft preparation, C.H. ; writing--review and editing, Z.X. ; formal analysis, Z.M. All authors have read and agreed to the published version of the manuscript.