# Simulation Tests on Granite Pillar Rockburst
## 5 Conclusions  
In this study, uniaxial compression rockburst tests were carried out on rock specimens containing a double rectangular cavern structure. By analyzing and discussing the real-time video, acoustic emission, bursting crater, debris, and other information obtained during the test, the main conclusions are as follows:  
1. The test simulated the underground mine pillars rockburst phenomenon. The real engineering structure was scaled down to 1/1000 and processed into a model specimen with a double rectangular chamber. The simulation test results and the real rockburst  
Figure 16: Stress concentration factor around the rectangular cavern with the different span–height ratio.  
Figure 15: Mapping the relationship between the rectangular stope and the unit circle (The letters A, B, C, D, E and F represent six points in different directions of the rectangle, and \(A^{\prime},B^{\prime},C^{\prime},D^{\prime},E^{\prime}\) and F\({}^{\prime}\) represent A, B, C, D, E and F mapping points in the circle).  
phenomenon were in agreement, demonstrating the validity of the experimental model and experimental methodology.
2. The rockburst of the ore pillars is divided into four stages, the calm period, the small particle ejection period, the block spalling period, and the full collapse period, and the displacement field monitored by DIC corresponds to the above four stages. Starting from the small particle ejection phase, the rock fissures gradually developed into macrorupture zones through the processes of sprouting, extending, and penetrating inward, and finally formed the rockburst crater contour, which demonstrated the reliability of the simulation experiments.
3. The event rate and energy rate of the acoustic emission test repeatedly increased and then decreased, exhibiting a multi-peak state. The cumulative number of acoustic emission events and the cumulative energy displayed stepwise growth. The test's acoustic emission event rate and energy rate are relatively low in stage I, gradually increase from stage II to stage IV, and reach their maximum values in stage V.
4. Large debris fragments greater than 5 mm make up the majority of rockburst debris, and the debris's morphology primarily resembles a thin plate, which is comparable to the shape features of engineering rockburst debris. The gradation of the rockburst debris is uniform, and the average value of the fractal dimension is 2.02. Burst crater damage is mainly in the middle pillar and the pillar above the part, the middle pillar after the destruction of the obvious deep \"V\" shape.  
X.X.: conceptualization, methodology, writing--original draft, investigation, and data curation; K.Z.: supervision, conceptualization, and writing--review and editing; P.Z.: resources and data curation; L.X.: conceptualization and methodology; D.L.: investigation and formal analysis; C.G.: resources, data curation, and writing--review and editing; Y.C.: software and visualization. All authors have read and agreed to the published version of the manuscript.  
The authors gratefully acknowledge financial support from the National Natural Science Foundation of China (52164004, 52104086), the key research and development program of Jiangxi Province, China (20212 BBG71009), the Science and technology project of Jiangxi Provincial Department of Education, China (GJ)2203604, GJJ2200824), and the post-doctoral research program of Jiangxi Province, China (2020 KY39). We thank the anonymous reviewers for their comments on our paper.  
Not applicable.  
Some or all data or models that support the findings of this study are available from the corresponding author upon reasonable request.  
The authors declare no conflicts of interest.