Dynamic Evolution of Coal Pore-Fracture Structure and Its Fractal Characteristics under the Action of Salty Solution
The instability and failure of coal pillars is one of the important factors leading to the catastrophic consequences of coal mine goaf collapse. Coal mine water has the characteristics of high salinity. Long-term mine water erosion can easily deform the coal pillar structure, eventually leading to i...
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| פורמט: | Article |
| שפה: | English |
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MDPI AG
2023-12-01
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| סדרה: | Mathematics |
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| גישה מקוונת: | https://www.mdpi.com/2227-7390/12/1/72 |
| _version_ | 1827384688138780672 |
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| author | Min Wang Yakun Tian Zhijun Zhang Qifeng Guo Lingling Wu |
| author_facet | Min Wang Yakun Tian Zhijun Zhang Qifeng Guo Lingling Wu |
| author_sort | Min Wang |
| collection | DOAJ |
| description | The instability and failure of coal pillars is one of the important factors leading to the catastrophic consequences of coal mine goaf collapse. Coal mine water has the characteristics of high salinity. Long-term mine water erosion can easily deform the coal pillar structure, eventually leading to instability and damage. This study carried out tests on coal samples soaked in salt solutions with different concentrations, and the nuclear magnetic resonance (NMR) method was used to obtain the dynamic evolution of the pore-fracture structure of coal. On the basis of fractal theory, the changes in fractal dimension of pore structure during the soaking process were discussed. The damage variable based on the pore fractal dimension was defined and the evolution relationship between the damage variable and immersion time was characterized. The findings demonstrated that the porosity change rate has an exponentially increasing relationship with the immersion time, and with the increasement of concentration of salt solution, the porosity change rate also shows increasing trends. The number of seepage pores and total pores increased with the immersion time. While, with the extension of soaking time, the number of adsorption pores first increased and then decreased. The connectivity between pores was enhanced. The relationship between the fractal dimension and the immersion time is linearly decreasing. The damage variable showed an increasing trend with the immersion time. As the concentration of salt solution increased, the damage of coal increased. The research results are of great significance for rationally evaluating the stability of coal pillars and ensuring the safe operation of underground engineering. |
| first_indexed | 2024-03-08T15:02:57Z |
| format | Article |
| id | doaj.art-f802c82bc0464d4fa581bfab42933267 |
| institution | Directory Open Access Journal |
| issn | 2227-7390 |
| language | English |
| last_indexed | 2024-03-08T15:02:57Z |
| publishDate | 2023-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Mathematics |
| spelling | doaj.art-f802c82bc0464d4fa581bfab429332672024-01-10T15:03:30ZengMDPI AGMathematics2227-73902023-12-011217210.3390/math12010072Dynamic Evolution of Coal Pore-Fracture Structure and Its Fractal Characteristics under the Action of Salty SolutionMin Wang0Yakun Tian1Zhijun Zhang2Qifeng Guo3Lingling Wu4School of Resource & Environment and Safety Engineering, University of South China, Hengyang 421001, ChinaSchool of Resource & Environment and Safety Engineering, University of South China, Hengyang 421001, ChinaSchool of Resource & Environment and Safety Engineering, University of South China, Hengyang 421001, ChinaSchool of Civil and Resource Engineering, University of Science and Technology Beijing, Beijing 100083, ChinaSchool of Resource & Environment and Safety Engineering, University of South China, Hengyang 421001, ChinaThe instability and failure of coal pillars is one of the important factors leading to the catastrophic consequences of coal mine goaf collapse. Coal mine water has the characteristics of high salinity. Long-term mine water erosion can easily deform the coal pillar structure, eventually leading to instability and damage. This study carried out tests on coal samples soaked in salt solutions with different concentrations, and the nuclear magnetic resonance (NMR) method was used to obtain the dynamic evolution of the pore-fracture structure of coal. On the basis of fractal theory, the changes in fractal dimension of pore structure during the soaking process were discussed. The damage variable based on the pore fractal dimension was defined and the evolution relationship between the damage variable and immersion time was characterized. The findings demonstrated that the porosity change rate has an exponentially increasing relationship with the immersion time, and with the increasement of concentration of salt solution, the porosity change rate also shows increasing trends. The number of seepage pores and total pores increased with the immersion time. While, with the extension of soaking time, the number of adsorption pores first increased and then decreased. The connectivity between pores was enhanced. The relationship between the fractal dimension and the immersion time is linearly decreasing. The damage variable showed an increasing trend with the immersion time. As the concentration of salt solution increased, the damage of coal increased. The research results are of great significance for rationally evaluating the stability of coal pillars and ensuring the safe operation of underground engineering.https://www.mdpi.com/2227-7390/12/1/72coalpore-fracture structuresalt solutionfractal characteristics |
| spellingShingle | Min Wang Yakun Tian Zhijun Zhang Qifeng Guo Lingling Wu Dynamic Evolution of Coal Pore-Fracture Structure and Its Fractal Characteristics under the Action of Salty Solution Mathematics coal pore-fracture structure salt solution fractal characteristics |
| title | Dynamic Evolution of Coal Pore-Fracture Structure and Its Fractal Characteristics under the Action of Salty Solution |
| title_full | Dynamic Evolution of Coal Pore-Fracture Structure and Its Fractal Characteristics under the Action of Salty Solution |
| title_fullStr | Dynamic Evolution of Coal Pore-Fracture Structure and Its Fractal Characteristics under the Action of Salty Solution |
| title_full_unstemmed | Dynamic Evolution of Coal Pore-Fracture Structure and Its Fractal Characteristics under the Action of Salty Solution |
| title_short | Dynamic Evolution of Coal Pore-Fracture Structure and Its Fractal Characteristics under the Action of Salty Solution |
| title_sort | dynamic evolution of coal pore fracture structure and its fractal characteristics under the action of salty solution |
| topic | coal pore-fracture structure salt solution fractal characteristics |
| url | https://www.mdpi.com/2227-7390/12/1/72 |
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