Dynamic Mechanical and Microstructural Properties of Outburst-Prone Coal Based on Compressive SHPB Tests

Zhenhua Yang, Chaojun Fan, Tianwei Lan, Sheng Li, Guifeng Wang, Mingkun Luo and Hongwei Zhang
Additional contact information
Zhenhua Yang: College of Mining, Liaoning Technical University, Fuxin 123000, China
Chaojun Fan: College of Mining, Liaoning Technical University, Fuxin 123000, China
Tianwei Lan: College of Mining, Liaoning Technical University, Fuxin 123000, China
Sheng Li: College of Mining, Liaoning Technical University, Fuxin 123000, China
Guifeng Wang: State Key Laboratory of Coal Resources and Safe Mining, School of Mines, China University of Mining and Technology, Xuzhou 221116, China
Mingkun Luo: College of Mining, Liaoning Technical University, Fuxin 123000, China
Hongwei Zhang: College of Mining, Liaoning Technical University, Fuxin 123000, China

Energies, 2019, vol. 12, issue 22, 1-16

Abstract: Understanding the dynamic mechanical behaviors and microstructural properties of outburst-prone coal is significant for preventing coal and gas outbursts during underground mining. In this paper, the split Hopkinson pressure bar (SHPB) tests were completed to study the strength and micro-structures of outburst-prone coal subjected to compressive impact loading. Two suites of coals—outburst-prone and outburst-resistant—were selected as the experimental specimens. The characteristics of dynamic strength, failure processes, fragment distribution, and microstructure evolution were analyzed based on the obtained stress-strain curves, failed fragments, and scanning electron microscopy (SEM) and nuclear magnetic resonance (NMR) images. Results showed that the dynamic compressive strength inclined linearly with the applied strain rate approximately. The obtained dynamic stress-strain responses could be represented by a typical curve with stages of compression, linear elasticity, microcrack evolution, unstable crack propagation, and rapid rapture. When the loading rate was relatively low, fragments fell in tension. With an increase in loading rates, the fragments fell predominantly in shear. The equivalent particle size of coal fragments decreased with the applied strain rate. The Uniaxial compressive strength (UCS) of outburst-prone coal was smaller than that of resistant coal, resulting in its smaller equivalent particle size of coal fragments. Moreover, the impact loading accelerated the propagation of fractures within the specimen, which enhanced the connectivity within the porous coal. The outburst-prone coal with behaviors of low strength and sudden increase of permeability could easily initiate gas outbursts.

Keywords: outburst-prone coal; split Hopkinson pressure bar; dynamic strength; fragment distribution; microstructural characteristics (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2019
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

Downloads: (external link)
https://www.mdpi.com/1996-1073/12/22/4236/pdf (application/pdf)
https://www.mdpi.com/1996-1073/12/22/4236/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jeners:v:12:y:2019:i:22:p:4236-:d:284265

Access Statistics for this article

Energies is currently edited by Ms. Agatha Cao

More articles in Energies from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().