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| MICRO-CT EXPERIMENTAL STUDY OF CRACK EVOLUTION OF LIGNITE UNDER DIFFERENT TEMPERATURES |
| (Institute of Mining Technology,Taiyuan University of Technology,Taiyuan,Shanxi 030024,China) |
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Abstract The crack evolution of lignite from 20 ℃ to 600 ℃ is studied by using micro-CT system intuitively. The extension and evolution of original cracks and new microcracks are discussed in detail. The study results show as follows:(1) From 20 ℃ to 100 ℃,thermal cracking degree of lignite is moderate and just a few new microcracks initiate. (2) From 100 ℃ to 300 ℃,thermal cracking is acute;many new microcracks initiate and original cracks extend quickly. The original and new cracks spread,overlap and connect with each other and finally form a crack network. (3) From 300 ℃ to 500 ℃,the extension of microcrack is very slowly. (4) From 500 ℃ to 600 ℃,some microcracks have trend of closure. With the increase in temperature,the microcracks initiate in soft coal along the bedding of coal seam and are arrested to hard coal;some cracks perpendicular to bedding direction will split on the edge of hard coal layer and then extend along the bedding of coal seam. The extension rate of cracks parallel to bedding direction is greater than that perpendicular to bedding direction.
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Received: 30 April 2010
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LI Botao1, 2, 3, TAN Yuxuan1, LIN Haifei4, 5*, WEI Jianping1, 2, 3, ZHANG Hongtu1, 2, 3, LI Shugang4, 5, WEI Zongyong4, 5, WANG Pei4, LUO Rongwei4, LIU Yanwei1, 2, 3. Mechanical properties and mesoscopic damage evolution of coal under liquid-nitrogen freezing at different initial temperatures[J]. , 2026, 45(6): 1757-1772. |
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