Investigation on fracturing mechanisms of granite under combined multi-hole blasting and confining pressure

• Published in: Computers and geotechnics 2025-03, Vol.179, p.106955, Article 106955
• Main Authors: He, Chenglong, Mao, Xiang, Chen, Dayong, Liu, Yaqing
• Format: Article
• Language: English
• Subjects: Confining pressure; Fractal dimension; Numerical simulation; Rock blasting; Rock fracturing
• ISSN: 0266-352X
• DOI: 10.1016/j.compgeo.2024.106955

The difficulty caused by geo-stress is inevitable when it comes to deep rock excavation. The research study the effect of different cut blasting methods (three-hole cut and four-hole cut) on rock blasting result under confining pressure through numerical simulation and model experiment. Firstly, a series of blasting tests were conducted on one- to four-hole granite specimens with size of 360 × 360 × 100 mm. Then, an experimentally validated Riedel-Hiermaier-Thomal (RHT) model in LS-DYNA is employed to simulate rock blasting under different c pressure coefficient k (k = ph/pv, ph and pv are the horizontal pressure and vertical pressure, respectively). Finally, the mechanism of multi-hole rock blasting is more clearly explained through the fractal dimension and hoop tensile stress of numerical result. The numerical results reveals that the confining pressure generally inhibits the propagation of explosion-induced cracks, but it facilitates the crack coalescence between the boreholes in the direction of the maximum principal stress in the four-hole cut. Importantly, choosing the four-hole cut method can acquire a superior rock-breaking effect than the three-hole cut when the buried depth is over 370 m. This research can provide specific references for selecting the cut blasting method for deep rock excavation at different underground depths.