| Autor: |
Ji, Dongliang, Zhao, Hongbao, Vanapalli, Sai K. |
| Předmět: |
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| Zdroj: |
Natural Resources Research; Apr2023, Vol. 32 Issue 2, p619-647, 29p |
| Abstrakt: |
Information of rock strength under dynamic loading conditions is required in many engineering applications. In this study, a specially designed impact loading device was developed for studying the dynamic characteristics of coal samples. Nuclear magnetic resonance measurements were carried out to evaluate the microcracking in samples using different impact energies with various constraints. The results suggest that the change in constraints plays a crucial role in influencing the strength and deformation properties of the samples. Samples without constraint were more damaged. Under the unilateral constraint condition, the cumulative damage of the samples was greatly reduced with increasing pre-stress. The samples were least damaged under the biaxial constraint condition, when the ratio of pre-stress was 1:1. However, the samples suffered significant damage if pre-stress in one direction remained unchanged and if the pre-stress in the other direction increased gradually, especially during the initial period. Additionally, a constitutive model was developed to reproduce the damage evolution and quantitative characterization, which showed good consistency with the experimental results. More importantly, the intrinsic mechanism of energy dissipation for coal samples undergoing deformation was also explained by mechanical analysis. The results provided a rational basis for understanding coal failures under various pre-stressed conditions. [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
| Externí odkaz: |
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