.png){kind=icon}
.png){kind=icon}
Return
Fractal Characterization and Fracture Mechanism of Multi-Face Unloading Rockburst in Deep Hard Rock
.png){kind=icon}
OA
AI
B
K
P
D
Y
H
DOI：10.3390/fractalfract10080522.png)
.png){kind=icon}
Original request for help.png){kind=icon}
Share.png){kind=icon}
Save
Abstract
En 中文
Rockburst in deep hard rock is strongly affected by excavation-induced unloading and the formation of free surfaces. Previous true-triaxial studies have mainly focused on rockburst behavior under single-face unloading; whereas, the progressive variations in strength response and fracture mechanism under multi-face unloading remain insufficiently understood. In this study, true triaxial single-face unloading tests were performed, and the micro-fracturing mechanism was revealed using SEM. In addition, the multi-face unloading discrete element models were established using PFC3D, and the failure behavior and fractal characterization of deep hard rock under different unloading faces were systematically investigated. The results demonstrated that crack propagation is controlled by local stress concentration, mineral resistance, and rapid elastic energy release. With increasing unloading face number, the failure pattern changes from boundary-localized spalling to multidirectional crack coalescence and global fragmentation. The peak stress decreases from 197 MPa to 143 MPa, while the axial strain decreases from 1.86 × 10−2 to 0.78 × 10−2, indicating that rockburst instability occurs at lower axial stress and strain levels. Furthermore, the evolution characteristics of crack network were quantitatively characterized using fractal theory, and the fractal dimension increased from 1.664 to 1.828, reflecting greater spatial occupation, connectivity, and geometric complexity.
Keywords:
deep hard rock
multi-face unloading
SEM
PFC3D
fractal theory
Journal
IF:
3.3
Papers:
4.2K
Citations:
7.6K
Organization
Cited Papers