Effects of gas diffusion from fractures to coal matrix on the evolution of coal strains: Experimental observations
文献类型：期刊论文
| 作者 | Wang, Chunguang2,3,4; Liu, Jishan1,5; Feng, Jili3; Wei, Mingyao4; Wang, Changsheng2; Jiang, Yujing2 |
| 刊名 | INTERNATIONAL JOURNAL OF COAL GEOLOGY
 |
| 出版日期 | 2016 |
| 卷号 | 162页码:74-84 |
| 关键词 | Gas diffusion Effective stress Coal strain Pore pressure |
| ISSN号 | 0166-5162 |
| DOI | 10.1016/j.coal.2016.05.012 |
| 英文摘要 | In this study, we investigate coal matrix swelling during the process of gas diffusion from cleats and its impact on the evolution of strain. We inject helium into both jacketed and unjacketed coal samples within a pressurized core holder. In the unjacketed experiment, the coal sample was exposed to hydrostatic gas pressure. In the jacketed experiment, the coal sample was constrained by fixed displacement at the two ends and by constant confining pressure laterally. In both experiments, strains were measured continuously both parallel/perpendicular to the bedding plane of the coal as internal pressure of helium is increased. For the unjacketed test the initial rapid compactive deformation of the sample rebounds to dilative at long term attributed to the gas diffusion-induced swelling of the coal matrix. For the jacketed test both axial and circumferential coal strains are first dilative due to the decrease in effective stress with subsequent changes of coal strain induced by the gas diffusion closely associated with the specific boundary conditions. For a constant stress boundary, the circumferential strain first remains unchanged for some time and then gradually increases to steady state. Such a phenomenon suggests that when gas diffuses from the cleat to the matrix, the coal matrix-cleat system probably undergoes a transition from local swelling to macroswelling. In contrast, for a fixed displacement boundary, the axial strain first decreases and then reaches a steady state. It also indicates that the swelling of the matrix not only decreases the aperture of the fracture, but also expands the circumferential profile of the coal sample due to the Poisson effect. In addition, helium diffusion in the matrix is estimated by using the bidisperse diffusion model. The calculated effective diffusivity increases with pore pressure. This suggested that the gas diffusion coefficient is a pore pressure-dependent parameter. These results demonstrate that gas diffusion from the cleat to the matrix can cause the swelling of the coal matrix, change the aperture of the cleat, and in turn impact the evolution of the coal permeability. (C) 2016 Elsevier B.V. All rights reserved. |
| WOS研究方向 | Energy & Fuels ; Geology |
| 语种 | 英语 |
| WOS记录号 | WOS:000380079200008 |
| 出版者 | ELSEVIER SCIENCE BV |
| 源URL | [http://119.78.100.198/handle/2S6PX9GI/3874]  |
| 专题 | 岩土力学所知识全产出_期刊论文 国家重点实验室知识产出_期刊论文 |
| 作者单位 | 1.Univ Western Australia, Sch Mech & Chem Engn ; 2.Shandong Univ Sci & Technol, State Key Lab Min Disaster Prevent & Control; 3.China Univ Min & Technol Beijing, State Key Lab Geomech & Deep Underground Engn ; 4.Chinese Acad Sci, Inst Rock & Soil Mech ; 5.Northeastern Univ |
| 推荐引用方式 GB/T 7714 | Wang, Chunguang,Liu, Jishan,Feng, Jili,et al. Effects of gas diffusion from fractures to coal matrix on the evolution of coal strains: Experimental observations[J]. INTERNATIONAL JOURNAL OF COAL GEOLOGY,2016,162:74-84. |
| APA | Wang, Chunguang,Liu, Jishan,Feng, Jili,Wei, Mingyao,Wang, Changsheng,&Jiang, Yujing.(2016).Effects of gas diffusion from fractures to coal matrix on the evolution of coal strains: Experimental observations.INTERNATIONAL JOURNAL OF COAL GEOLOGY,162,74-84. |
| MLA | Wang, Chunguang,et al."Effects of gas diffusion from fractures to coal matrix on the evolution of coal strains: Experimental observations".INTERNATIONAL JOURNAL OF COAL GEOLOGY 162(2016):74-84. |
入库方式： OAI收割
来源：武汉岩土力学研究所
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