Experimental Study on the Dynamic Characteristics of Fractured Coal Under Cumulative Impact
The dynamic characteristics of fractured coal under cumulative impact are an important basis for evaluating the safety and stability of mining engineering. In order to study the dynamic mechanical properties of fractured coal under cumulative impact, the split-Hopkinson pressure bar (SHPB) device is...
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| Main Authors: | , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-06-01
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| Series: | Applied Sciences |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2076-3417/15/12/6469 |
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| Summary: | The dynamic characteristics of fractured coal under cumulative impact are an important basis for evaluating the safety and stability of mining engineering. In order to study the dynamic mechanical properties of fractured coal under cumulative impact, the split-Hopkinson pressure bar (SHPB) device is used to conduct dynamic impact tests on fractured coal under cumulative impact. The wave velocity variation, dynamic compressive strength, fractal characteristics of fragmentation and energy dissipation properties of fractured coal samples under different impact times are analyzed. The results indicate that as the number of cumulative impacts increases, the decreasing trend of wave velocity of the coal samples conforms to the linear change relationship, and the rate of reduction varies with fracture inclination angles, demonstrating an inclination-dependent behavior. The dynamic compressive strength and energy dissipation rate of coal samples continuously decrease with the increase in cumulative impact times. The dynamic strength of the samples decreases approximately 25–40% after five time impacts. Coal samples with a fracture inclination angle of 30° show the largest decrease in dynamic compressive strength and are most prone to failure. As the number of cumulative impacts increases, the fractal dimension of the coal samples gradually increases, and the fragmentation mode transitions from large-size block failure to fine-grain pulverization. The failure mechanism converts from tensile failure to a mixed tensile–shear failure mode. The research findings provide a scientific basis for studying the mechanism of dynamic disasters in fractured coal samples under disturbance impact. |
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| ISSN: | 2076-3417 |