Affiliation:
1. Guizhou University
2. Guizhou Panjiang Coal & Electricity Group Technology Research Institute Co.，Guizhou
3. Bijie Zhongcheng Energy Co. LTD
Abstract
Abstract
Investigation of the dynamic mechanical properties of coal rock under complex stress conditions at depth. In this work, based on the improved Separate Hopkinson Pressure Bar Test System, 15 groups of coal samples were used to perform dynamic impact tests under different conditions. The changing rules of dynamic strength, crushing, fractal dimension and damage modes of coal under different stress conditions were analyzed. And 9 groups of coal specimens were selected for numerical simulation using ANSYS/LS-DYNA. The results show that: (1) The stress-strain curves of coal specimens under different strain rates, different circumferential pressures and axial pressures basically have the same trend of a bimodal phenomenon. (2) The peak dynamic stress of the coal specimens increased linearly with the increase of strain rate and confining pressure, and the ambient pressure limited the expansion of the internal cracks of the coal specimens under impact loading. And based on the experimental and simulation data, the maximum relative errors between the two are derived as (Group A: 2.9578%, Group B: 6.177%, Group C:6.382%) (3) The damage modes of the coal specimens under the three-dimensional dynamic-static combined loading were mainly "X" type and "conical" shear damage modes. The fractal dimension increases with the increase of strain rate, decreases with the increase of circumferential pressure, and first decreases and then increases with the increase of axial pressure.
Publisher
Research Square Platform LLC
Reference43 articles.
1. 1. Xie Heping, Gao Feng, Ju Yang༎ Research and developmentof rock mechanics in deep ground engineering [J] ༎ Chinese Journal of Rock Mechanics and Engineering, 2015, 34( 11) :2161 - 2178༎
2. 2. HE Man-chao. Present state and perspective of rock mechanics in deep mining engineering [C]// Proceedings of the 8th Rock Mechanics and Engineering Conference. Beijing: Science Press, 2004: 88–94.
3. 3. QIAN Qi-hu. The current development of nonlinear rock mechanics: The mechanics problems of deep rock mass [C]// Proceedings of the 8th Rock Mechanics and Engineering Conference. Beijing: Science Press, 2004: 10–17.
4. 4. Ray SK, Khan AM, Mohalik NK, Mishra D, Mandal S, Pandey JK, et al. Review ofpreventive and constructive measures for coal mine explosions: an Indianperspective. Int J Min Sci Technol 2022;32(3):471–85.
5. 5. Mohammad RK, Kerstin W. A review on split Hopkinson bar experiments on the dynamic characterisation of concrete. Constr Build Mater 2018;190:1264–83.