Effect of Borehole Pressure Relief on Rockburst: Insights from Borehole Cooperative Deformation Mechanism

To study how borehole pressure relief (BPR) prevents rockburst in the surrounding rocks, granite specimens with different borehole configurations were tested using true triaxial single-side unloading tests. The prevention mechanism of BPR and the effect of the number of boreholes on rockburst intensity were analyzed on mechanical behavior and energy evolution. The results show that rockburst intensity decreases as the number of boreholes increases, indicated by a reduction in both the kinetic energy of ejected fragments and the rockburst pit area. The deformation of borehole also increases simultaneously, with high-amplitude acoustic emission (AE) signals occurring earlier. Additionally, this study proposes a mechanism of cooperative borehole deformation, which quantitatively analyzes the influence range of BPR, highlights the differences between single and multiple borehole effects, and provides a scientific basis for optimizing the design and layout of boreholes.