To investigate the influence of fissure angle on the dynamic tensile properties and failure behavior of coal with prefabricated parallel double fissures, dynamic splitting tests were conducted on coal samples containing prefabricated parallel double fissures using a split Hopkinson pressure bar (SHPB) test system. The dynamic failure process of coal was recorded simultaneously. The dynamic mechanical properties and crack evolution patterns of coal with different fissure angles (0°, 30°, 45°, 60°, 75°, and 90°) were analyzed, and the crack propagation fractal characteristics and energy evolution were discussed. The results show that: The peak load ranges from 1.17 to 2.03 kN, exhibiting an overall trend of first increasing, then decreasing, and subsequently increasing again with increasing fissure angles. All samples predominantly fail in tensile mode, with cracks developing along the loading direction. Initial cracks occur at the sample center (the area near the line connecting the two loading points), followed by anti-wing cracks at the prefabricated fissure and shear cracks at contact interfaces between samples and pressure bars. These cracks further propagate and coalesce to form fracture surfaces. The fractal dimension of crack propagation ranges from 1.76 to 1.83, showing an increasing trend during loading. The maximum fractal dimension at failure occurs at 75° fissure angle, while the minimum value appears at 60°. The evolution of absorbed energy followed “S”-shaped growth patterns, which can be divided into an initial stable phase, a rapid growth phase, and a slow growth phase.
Liu Bin
,
Li Yongnan
,
Zhang Tong
,
Wu Yang
,
Jin Mengqi
. Dynamic Splitting Behaviors and Crack Evolution of Coal with Prefabricated Parallel Double Fissures[J]. Chinese Journal of Underground Space and Engineering, 2025
, 21(S2)
: 606
-614
.
DOI: 10.20174/j.JUSE.2025.S2.09
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