Acoustic Emission and Failure Modes for Coal-Rock Structure under Different Loading Rates
Coal bump refers to a sudden catastrophic failure of coal seam and usually causes serious damages to underground mining facilities and staff. Considering the combined coal-rock structure for coal bumps, failure process and acoustic emission (AE) characteristics of combined coal-sandstone samples und...
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| Format: | Article |
| Language: | English |
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Wiley
2018-01-01
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| Series: | Advances in Civil Engineering |
| Online Access: | http://dx.doi.org/10.1155/2018/9391780 |
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| author | Ning Wang Yingqian Xu Dengyuan Zhu Nan Wang Benfu Yu |
| author_facet | Ning Wang Yingqian Xu Dengyuan Zhu Nan Wang Benfu Yu |
| author_sort | Ning Wang |
| collection | DOAJ |
| description | Coal bump refers to a sudden catastrophic failure of coal seam and usually causes serious damages to underground mining facilities and staff. Considering the combined coal-rock structure for coal bumps, failure process and acoustic emission (AE) characteristics of combined coal-sandstone samples under different loading rates were studied by uniaxial compression tests, and three basic failure modes and bump proneness for coal-rock structure were obtained. The following conclusions are drawn: (1) when loading rate was relatively low, plastic deformation of coal mass fully developed, while surface cracks of coal mass was not apparent and slip along the transfixion crack occurred in the postpeak stage; (2) with the increase in loading rate, surface tensile cracks developed into splitting cracks at the end of the prepeak stage and throughout the postpeak stage, and brittle failure finally happened due to the release of nonlinear step-shaped energy or one-time strain energy release of upper rock mass, resulting in the damage of internal bearing structure and weakening of bearing capacity; (3) the deformation and failure process of combined samples showed obvious phases, and corresponding AE energy release rate could be divided into periodic linear growth and transient growth, while the cumulative energy of AE events has multiple peak points and transient growth with the increase of loading rate; (4) it was demonstrated that two distinct frequency bands existed in AE events, which were about 50 kHz and 150 kHz, and the distribution of AE events near 50 kHz was larger and stronger, representing the main frequency range of cracks in coal mass. According to the damage characteristics and AE parameters for combined samples, an brittle model for coal-rock structure with mutation characteristics was proposed, and three basic failure modes for the combined structure with the increase of loading rate were progressive shear failure, splitting failure, and structural failure, respectively. |
| format | Article |
| id | doaj-art-2786115556454cc8ad281561755aa805 |
| institution | Kabale University |
| issn | 1687-8086 1687-8094 |
| language | English |
| publishDate | 2018-01-01 |
| publisher | Wiley |
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| series | Advances in Civil Engineering |
| spelling | doaj-art-2786115556454cc8ad281561755aa8052025-02-03T06:11:26ZengWileyAdvances in Civil Engineering1687-80861687-80942018-01-01201810.1155/2018/93917809391780Acoustic Emission and Failure Modes for Coal-Rock Structure under Different Loading RatesNing Wang0Yingqian Xu1Dengyuan Zhu2Nan Wang3Benfu Yu4School of Civil Engineering and Architecture, Linyi University, Linyi 276005, ChinaDepartment of Solid Mechanics, Kazan (Volga Region) Federal University, Kazan 420008, RussiaSchool of Civil Engineering and Architecture, Linyi University, Linyi 276005, ChinaSchool of Civil Engineering and Architecture, Linyi University, Linyi 276005, ChinaSchool of Civil Engineering and Architecture, Linyi University, Linyi 276005, ChinaCoal bump refers to a sudden catastrophic failure of coal seam and usually causes serious damages to underground mining facilities and staff. Considering the combined coal-rock structure for coal bumps, failure process and acoustic emission (AE) characteristics of combined coal-sandstone samples under different loading rates were studied by uniaxial compression tests, and three basic failure modes and bump proneness for coal-rock structure were obtained. The following conclusions are drawn: (1) when loading rate was relatively low, plastic deformation of coal mass fully developed, while surface cracks of coal mass was not apparent and slip along the transfixion crack occurred in the postpeak stage; (2) with the increase in loading rate, surface tensile cracks developed into splitting cracks at the end of the prepeak stage and throughout the postpeak stage, and brittle failure finally happened due to the release of nonlinear step-shaped energy or one-time strain energy release of upper rock mass, resulting in the damage of internal bearing structure and weakening of bearing capacity; (3) the deformation and failure process of combined samples showed obvious phases, and corresponding AE energy release rate could be divided into periodic linear growth and transient growth, while the cumulative energy of AE events has multiple peak points and transient growth with the increase of loading rate; (4) it was demonstrated that two distinct frequency bands existed in AE events, which were about 50 kHz and 150 kHz, and the distribution of AE events near 50 kHz was larger and stronger, representing the main frequency range of cracks in coal mass. According to the damage characteristics and AE parameters for combined samples, an brittle model for coal-rock structure with mutation characteristics was proposed, and three basic failure modes for the combined structure with the increase of loading rate were progressive shear failure, splitting failure, and structural failure, respectively.http://dx.doi.org/10.1155/2018/9391780 |
| spellingShingle | Ning Wang Yingqian Xu Dengyuan Zhu Nan Wang Benfu Yu Acoustic Emission and Failure Modes for Coal-Rock Structure under Different Loading Rates Advances in Civil Engineering |
| title | Acoustic Emission and Failure Modes for Coal-Rock Structure under Different Loading Rates |
| title_full | Acoustic Emission and Failure Modes for Coal-Rock Structure under Different Loading Rates |
| title_fullStr | Acoustic Emission and Failure Modes for Coal-Rock Structure under Different Loading Rates |
| title_full_unstemmed | Acoustic Emission and Failure Modes for Coal-Rock Structure under Different Loading Rates |
| title_short | Acoustic Emission and Failure Modes for Coal-Rock Structure under Different Loading Rates |
| title_sort | acoustic emission and failure modes for coal rock structure under different loading rates |
| url | http://dx.doi.org/10.1155/2018/9391780 |
| work_keys_str_mv | AT ningwang acousticemissionandfailuremodesforcoalrockstructureunderdifferentloadingrates AT yingqianxu acousticemissionandfailuremodesforcoalrockstructureunderdifferentloadingrates AT dengyuanzhu acousticemissionandfailuremodesforcoalrockstructureunderdifferentloadingrates AT nanwang acousticemissionandfailuremodesforcoalrockstructureunderdifferentloadingrates AT benfuyu acousticemissionandfailuremodesforcoalrockstructureunderdifferentloadingrates |