Acoustic Emission Characteristics of Gas-Containing Coal during Loading Dilation Process
Raw coal was used as the study object in this paper to identify the evolution characteristics of acoustic emission (AE) during the dilation process of gas-containing coal. The coal specimens were stored in gas seal devices filled with gas at different pressures (0, 0.5, 1.0, and 1.5 MPa) for 24 h...
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Eastern Macedonia and Thrace Institute of Technology
2015-12-01
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| Series: | Journal of Engineering Science and Technology Review |
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| Online Access: | http://www.jestr.org/downloads/Volume8Issue5/fulltext85132015.pdf |
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| author | Z. Q. Yin G. X. Xie L. Wang Z. X. Hu Y. Zou |
| author_facet | Z. Q. Yin G. X. Xie L. Wang Z. X. Hu Y. Zou |
| author_sort | Z. Q. Yin |
| collection | DOAJ |
| description | Raw coal was used as the study object in this paper to identify the evolution characteristics of acoustic emission (AE)
during the dilation process of gas-containing coal. The coal specimens were stored in gas seal devices filled with gas at
different pressures (0, 0.5, 1.0, and 1.5 MPa) for 24 h prior to testing. Then, the specimens were tested in a rock-testing
machine, and the deformation and crack fracture patterns were recorded by using strain gauges and an AE system. The
axial and volumetric strains–stress curves were analyzed in relation to the AE and the failure mode. Results show that as
gas pressure increases, the uniaxial compression strength and elasticity modulus of gas-containing coal decreases,
whereas the Poisson’s ratio increases. In all the coal specimens, the dilation initiation stress decreases, and the dilation
degree increases. During the dilation process, before the loaded coal specimens reach peak stress, and as the load
increases, the changes in the specimens and in the AE energy parameter of specimens can be divided into four phases:
crack closure deformation, elastic deformation, stable crack propagation, and unstable crack propagation (dilation
process). Across the four phases, the AE energy increases evidently during crack closure and elastic deformation but
decreases during stable crack propagation. As the gas pressure increases, the AE signal frequency increases from 4.5 KHz
to 8.1 KHz during the dilation process. Thus, the gas presence in coal specimens exerts a significant influence on the
closure of sample cracks and dilation damage. |
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| institution | Directory Open Access Journal |
| issn | 1791-2377 1791-2377 |
| language | English |
| last_indexed | 2024-12-11T13:18:21Z |
| publishDate | 2015-12-01 |
| publisher | Eastern Macedonia and Thrace Institute of Technology |
| record_format | Article |
| series | Journal of Engineering Science and Technology Review |
| spelling | doaj.art-610371d70fb64b89b2ff21541a6fa3b02022-12-22T01:05:57ZengEastern Macedonia and Thrace Institute of TechnologyJournal of Engineering Science and Technology Review1791-23771791-23772015-12-018595101Acoustic Emission Characteristics of Gas-Containing Coal during Loading Dilation ProcessZ. Q. Yin0G. X. Xie1L. Wang2Z. X. Hu3Y. Zou4he Provincial Key Laboratory of mining effects & disasters preventing under deep mining in Anhui, Anhui University of Science and Technology, Huainan, 232001-China / Sch. of Mineral & Safety, Anhui University of Science and Technology, Huainan, 232001, China he Provincial Key Laboratory of mining effects & disasters preventing under deep mining in Anhui, Anhui University of Science and Technology, Huainan, 232001-China / Sch. of Mineral & Safety, Anhui University of Science and Technology, Huainan, 232001, China he Provincial Key Laboratory of mining effects & disasters preventing under deep mining in Anhui, Anhui University of Science and Technology, Huainan, 232001-China / Sch. of Mineral & Safety, Anhui University of Science and Technology, Huainan, 232001, China he Provincial Key Laboratory of mining effects & disasters preventing under deep mining in Anhui, Anhui University of Science and Technology, Huainan, 232001-China / Sch. of Mineral & Safety, Anhui University of Science and Technology, Huainan, 232001, China Lab. for Rock Mechanics (LMR), École polytechnique fédérale de Lausanne (EPFL), Lausanne, CH 1015, SwitzerlandRaw coal was used as the study object in this paper to identify the evolution characteristics of acoustic emission (AE) during the dilation process of gas-containing coal. The coal specimens were stored in gas seal devices filled with gas at different pressures (0, 0.5, 1.0, and 1.5 MPa) for 24 h prior to testing. Then, the specimens were tested in a rock-testing machine, and the deformation and crack fracture patterns were recorded by using strain gauges and an AE system. The axial and volumetric strains–stress curves were analyzed in relation to the AE and the failure mode. Results show that as gas pressure increases, the uniaxial compression strength and elasticity modulus of gas-containing coal decreases, whereas the Poisson’s ratio increases. In all the coal specimens, the dilation initiation stress decreases, and the dilation degree increases. During the dilation process, before the loaded coal specimens reach peak stress, and as the load increases, the changes in the specimens and in the AE energy parameter of specimens can be divided into four phases: crack closure deformation, elastic deformation, stable crack propagation, and unstable crack propagation (dilation process). Across the four phases, the AE energy increases evidently during crack closure and elastic deformation but decreases during stable crack propagation. As the gas pressure increases, the AE signal frequency increases from 4.5 KHz to 8.1 KHz during the dilation process. Thus, the gas presence in coal specimens exerts a significant influence on the closure of sample cracks and dilation damage.http://www.jestr.org/downloads/Volume8Issue5/fulltext85132015.pdfDilation initiation stress; Gas-containing coal; Acoustic emission; Energy; Signal frequency ____________ |
| spellingShingle | Z. Q. Yin G. X. Xie L. Wang Z. X. Hu Y. Zou Acoustic Emission Characteristics of Gas-Containing Coal during Loading Dilation Process Journal of Engineering Science and Technology Review Dilation initiation stress; Gas-containing coal; Acoustic emission; Energy; Signal frequency ____________ |
| title | Acoustic Emission Characteristics of Gas-Containing Coal during Loading Dilation Process |
| title_full | Acoustic Emission Characteristics of Gas-Containing Coal during Loading Dilation Process |
| title_fullStr | Acoustic Emission Characteristics of Gas-Containing Coal during Loading Dilation Process |
| title_full_unstemmed | Acoustic Emission Characteristics of Gas-Containing Coal during Loading Dilation Process |
| title_short | Acoustic Emission Characteristics of Gas-Containing Coal during Loading Dilation Process |
| title_sort | acoustic emission characteristics of gas containing coal during loading dilation process |
| topic | Dilation initiation stress; Gas-containing coal; Acoustic emission; Energy; Signal frequency ____________ |
| url | http://www.jestr.org/downloads/Volume8Issue5/fulltext85132015.pdf |
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