Numerical Study on the Mechanism of Coal and Gas Outburst in the Coal Seam Thickening Area during Mining
Most coal and gas outbursts occur in the coal thickness variation zone. However, it is difficult to illustrate the mechanism of outbursts in coal thickening areas by physical simulation experiments. In this study, a coupled multi-field model, established by considering the stress–strain field, gas t...
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MDPI AG
2023-04-01
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| author | Zhengshuai Liu Longyong Shu Zhonggang Huo Yongpeng Fan |
| author_facet | Zhengshuai Liu Longyong Shu Zhonggang Huo Yongpeng Fan |
| author_sort | Zhengshuai Liu |
| collection | DOAJ |
| description | Most coal and gas outbursts occur in the coal thickness variation zone. However, it is difficult to illustrate the mechanism of outbursts in coal thickening areas by physical simulation experiments. In this study, a coupled multi-field model, established by considering the stress–strain field, gas transport field and damage field, was used to investigate the evolution of stress, gas pressure and plastic failure zones under different variation gradients and amplitudes of coal thickness. The simulation results show that the stress peak at the coal thickening transition zone caused by mining is higher than that at the constant thickness coal seam. The stress peak at the coal thickening transition zone decreases from 18.8 MPa to 16.9 MPa with the increase in the transition zone from 0 m to 10 m under the constant coal thickness variation from 3 m to 7 m; while it increases from 16.2 MPa to 19.3 MPa with the increase in the transition zone from 2 m to 10 m under the constant coal thickness variation gradient of 45°. Similarly, the plastic deformation volume of the coal seam between the driving face and the coal thickening interface increases with the increase in the coal thickness variation gradient and amplitude. In addition, the gas pressure in the fracture declines slower in the coal thickness variation zone affected by the higher coal thickness variation gradients or amplitudes. The mechanism for outbursts occurring in the increasing coal thickness area was further discussed, and combined with the simulation results for the energy principle of outbursts. Compared with the constant thickness coal seam, the elastic energy increases from 1.85 MJ to 1.94 MJ, and the free gas expansion energy increases from 24.19 MJ to 50.57 MJ when the coal thickness varies from 3 m to 13 m within a 10 m transition zone. The variation of coal thickness causes higher stress, higher gas pressure and low coal strength, which triggers outbursts more easily. The research could provide the theoretical support to prevent and control outbursts in coal seam thickening areas during mining. |
| first_indexed | 2024-03-11T05:38:10Z |
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| id | doaj.art-d1430252acfd4a8e9783e7a571a22638 |
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| issn | 1996-1073 |
| language | English |
| last_indexed | 2024-03-11T05:38:10Z |
| publishDate | 2023-04-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Energies |
| spelling | doaj.art-d1430252acfd4a8e9783e7a571a226382023-11-17T16:39:57ZengMDPI AGEnergies1996-10732023-04-01167328810.3390/en16073288Numerical Study on the Mechanism of Coal and Gas Outburst in the Coal Seam Thickening Area during MiningZhengshuai Liu0Longyong Shu1Zhonggang Huo2Yongpeng Fan3Chinese Institute of Coal Science, Beijing 100013, ChinaChina Coal Research Institute, Beijing 100013, ChinaChina Coal Research Institute, Beijing 100013, ChinaChina Coal Research Institute, Beijing 100013, ChinaMost coal and gas outbursts occur in the coal thickness variation zone. However, it is difficult to illustrate the mechanism of outbursts in coal thickening areas by physical simulation experiments. In this study, a coupled multi-field model, established by considering the stress–strain field, gas transport field and damage field, was used to investigate the evolution of stress, gas pressure and plastic failure zones under different variation gradients and amplitudes of coal thickness. The simulation results show that the stress peak at the coal thickening transition zone caused by mining is higher than that at the constant thickness coal seam. The stress peak at the coal thickening transition zone decreases from 18.8 MPa to 16.9 MPa with the increase in the transition zone from 0 m to 10 m under the constant coal thickness variation from 3 m to 7 m; while it increases from 16.2 MPa to 19.3 MPa with the increase in the transition zone from 2 m to 10 m under the constant coal thickness variation gradient of 45°. Similarly, the plastic deformation volume of the coal seam between the driving face and the coal thickening interface increases with the increase in the coal thickness variation gradient and amplitude. In addition, the gas pressure in the fracture declines slower in the coal thickness variation zone affected by the higher coal thickness variation gradients or amplitudes. The mechanism for outbursts occurring in the increasing coal thickness area was further discussed, and combined with the simulation results for the energy principle of outbursts. Compared with the constant thickness coal seam, the elastic energy increases from 1.85 MJ to 1.94 MJ, and the free gas expansion energy increases from 24.19 MJ to 50.57 MJ when the coal thickness varies from 3 m to 13 m within a 10 m transition zone. The variation of coal thickness causes higher stress, higher gas pressure and low coal strength, which triggers outbursts more easily. The research could provide the theoretical support to prevent and control outbursts in coal seam thickening areas during mining.https://www.mdpi.com/1996-1073/16/7/3288coal and gas outburstcoal thickness variationmining stressgas pressureoutburst energy |
| spellingShingle | Zhengshuai Liu Longyong Shu Zhonggang Huo Yongpeng Fan Numerical Study on the Mechanism of Coal and Gas Outburst in the Coal Seam Thickening Area during Mining Energies coal and gas outburst coal thickness variation mining stress gas pressure outburst energy |
| title | Numerical Study on the Mechanism of Coal and Gas Outburst in the Coal Seam Thickening Area during Mining |
| title_full | Numerical Study on the Mechanism of Coal and Gas Outburst in the Coal Seam Thickening Area during Mining |
| title_fullStr | Numerical Study on the Mechanism of Coal and Gas Outburst in the Coal Seam Thickening Area during Mining |
| title_full_unstemmed | Numerical Study on the Mechanism of Coal and Gas Outburst in the Coal Seam Thickening Area during Mining |
| title_short | Numerical Study on the Mechanism of Coal and Gas Outburst in the Coal Seam Thickening Area during Mining |
| title_sort | numerical study on the mechanism of coal and gas outburst in the coal seam thickening area during mining |
| topic | coal and gas outburst coal thickness variation mining stress gas pressure outburst energy |
| url | https://www.mdpi.com/1996-1073/16/7/3288 |
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