IDEAS home Printed from https://ideas.repec.org/a/gam/jeners/v13y2020i24p6585-d461781.html
   My bibliography  Save this article

Experimental Investigation on the Tensile Strength of Coal: Consideration of the Specimen Size and Water Content

Author

Listed:
  • Honghua Song

    (School of Energy and Mining Engineering, China University of Mining and Technology, Beijing 100083, China)

  • Yixin Zhao

    (School of Energy and Mining Engineering, China University of Mining and Technology, Beijing 100083, China
    State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Beijing 100083, China)

  • Yaodong Jiang

    (State Key Laboratory of Coal Resources and Safe Mining, China University of Mining and Technology, Beijing 100083, China
    School of Mechanics and Civil Engineering, China University of Mining and Technology, Beijing 100083, China)

  • Weisheng Du

    (School of Civil Engineering, Tsinghua University, Beijing 100083, China)

Abstract

We experimentally and theoretically explored the microstructure-related effects of water and specimen size on the tensile strength of coal. Cylindrical coal specimens with different sizes (diameters of 25, 38, and 50 mm) and water contents (immersion time lengths: 0, 4, and 7 days) were processed. The microscopic features and mineral compositions of the coal samples were imaged and characterized via scanning electron microscopy (SEM) and X-ray diffraction (XRD). The physicochemical effects of water on the microstructures and coal matrices were investigated by acoustic emission (AE) and fractal theory. In this research, the tensile strength was found to be reduced in larger specimens, which can be explained by an exponential correlation. Water enhances the scale effect on the tensile strength of coal, although the water content decreases in larger specimens. Meanwhile, greater reductions in tensile strength were observed under the coupled effects of the water and specimen size. Based on the AE variation and fractal feature analysis, water was considered to mainly plays roles in dissolving clay minerals, softening the coal matrix, and lubricating cracks during the tensile failure of coal. In addition, the cumulative AE counts and absolute AE energy values decreased with the water content and increased with the specimen size. Similar variations were also observed in the fractal dimension, indicating the intensification of the AE activity concentration around the peak strength area in specimens with greater water contents, as well as a concentration reduction in larger specimen sizes with different water contents. The percentage of tensile failure increased in the diameter range of 25–38 mm and decreased in the range of 38–50 mm. Water increases the proportion of tensile strength generated during the tensile failure process, and this effects increases with the immersion time. Thus, consideration should be given to the combined water and scale effects when extrapolating lab-investigation results to water-related engineering issues in coal mines.

Suggested Citation

  • Honghua Song & Yixin Zhao & Yaodong Jiang & Weisheng Du, 2020. "Experimental Investigation on the Tensile Strength of Coal: Consideration of the Specimen Size and Water Content," Energies, MDPI, vol. 13(24), pages 1-18, December.
    • Handle: RePEc:gam:jeners:v:13:y:2020:i:24:p:6585-:d:461781
    as

    Download full text from publisher

    File URL: https://www.mdpi.com/1996-1073/13/24/6585/pdf
    Download Restriction: no
    File URL: https://www.mdpi.com/1996-1073/13/24/6585/
    Download Restriction: no
    ---><---

    References listed on IDEAS

    as
    1. Awad Ahmed Quosay & Dariusz Knez & Jan Ziaja, 2020. "Hydraulic fracturing: New uncertainty based modeling approach for process design using Monte Carlo simulation technique," PLOS ONE, Public Library of Science, vol. 15(7), pages 1-18, July.
    2. Zhang, Zhibo & Wang, Enyuan & Li, Nan, 2017. "Fractal characteristics of acoustic emission events based on single-link cluster method during uniaxial loading of rock," Chaos, Solitons & Fractals, Elsevier, vol. 104(C), pages 298-306.
    3. Wang, Chang'an & Wu, Song & Lv, Qiang & Liu, Xuan & Chen, Wufeng & Che, Defu, 2017. "Study on correlations of coal chemical properties based on database of real-time data," Applied Energy, Elsevier, vol. 204(C), pages 1115-1123.
    Full references (including those not matched with items on IDEAS)

    Most related items

    These are the items that most often cite the same works as this one and are cited by the same works as this one.
    1. Qu, Baolin & Wang, Jingxin & Zhu, Hongqing & Hu, Lintao & Liao, Qi, 2024. "Experimental study on evolution and mechanism for dielectric response of different rank coals in terahertz band," Energy, Elsevier, vol. 288(C).
    2. Stefan Zelenak & Erika Skvarekova & Andrea Senova & Gabriel Wittenberger, 2021. "The Usage of UCG Technology as Alternative to Reach Low-Carbon Energy," Energies, MDPI, vol. 14(13), pages 1-15, June.
    3. Herimitsinjo Rajaoalison & Dariusz Knez & Mohammad Ahmad Mahmoudi Zamani, 2022. "A Multidisciplinary Approach to Evaluate the Environmental Impacts of Hydrocarbon Production in Khuzestan Province, Iran," Energies, MDPI, vol. 15(22), pages 1-19, November.
    4. Zhao, Jingyu & Deng, Jun & Chen, Long & Wang, Tao & Song, Jiajia & Zhang, Yanni & Shu, Chi-Min & Zeng, Qiang, 2019. "Correlation analysis of the functional groups and exothermic characteristics of bituminous coal molecules during high-temperature oxidation," Energy, Elsevier, vol. 181(C), pages 136-147.
    5. Lü, Hui-Fei & Deng, Jun & Li, Da-Jiang & Xu, Fan & Xiao, Yang & Shu, Chi-Min, 2021. "Effect of oxidation temperature and oxygen concentration on macro characteristics of pre-oxidised coal spontaneous combustion process," Energy, Elsevier, vol. 227(C).
    6. Mohammad Ahmad Mahmoudi Zamani & Dariusz Knez, 2021. "A New Mechanical-Hydrodynamic Safety Factor Index for Sand Production Prediction," Energies, MDPI, vol. 14(11), pages 1-14, May.
    7. Wang, Pengqian & Wang, Chang'an & Yuan, Maobo & Wang, Chaowei & Zhang, Jinping & Du, Yongbo & Tao, Zichen & Che, Defu, 2020. "Experimental evaluation on co-combustion characteristics of semi-coke and coal under enhanced high-temperature and strong-reducing atmosphere," Applied Energy, Elsevier, vol. 260(C).
    8. Li, Hongjun & Chang, Qinghua & Gao, Rui & Dai, Zhenghua & Chen, Xueli & Yu, Guangsuo & Wang, Fuchen, 2018. "Fractal characteristics and reactivity evolution of lignite during the upgrading process by supercritical CO2 extraction," Applied Energy, Elsevier, vol. 225(C), pages 559-569.
    9. Chuangye Wang & Xinke Chang & Yilin Liu & Shijiang Chen, 2019. "Mechanistic Characteristics of Double Dominant Frequencies of Acoustic Emission Signals in the Entire Fracture Process of Fine Sandstone," Energies, MDPI, vol. 12(20), pages 1-17, October.
    10. Mitra Khalilidermani & Dariusz Knez & Mohammad Ahmad Mahmoudi Zamani, 2021. "Empirical Correlations between the Hydraulic Properties Obtained from the Geoelectrical Methods and Water Well Data of Arak Aquifer," Energies, MDPI, vol. 14(17), pages 1-19, August.
    11. Mohammad Ahmad Mahmoudi Zamani & Dariusz Knez, 2023. "Experimental Investigation on the Relationship between Biot’s Coefficient and Hydrostatic Stress for Enhanced Oil Recovery Projects," Energies, MDPI, vol. 16(13), pages 1-13, June.
    12. Xu, Jun & Tang, Hao & Su, Sheng & Liu, Jiawei & Xu, Kai & Qian, Kun & Wang, Yi & Zhou, Yingbiao & Hu, Song & Zhang, Anchao & Xiang, Jun, 2018. "A study of the relationships between coal structures and combustion characteristics: The insights from micro-Raman spectroscopy based on 32 kinds of Chinese coals," Applied Energy, Elsevier, vol. 212(C), pages 46-56.
    13. Ion Pană & Iuliana Veronica Gheţiu & Ioana Gabriela Stan & Florinel Dinu & Gheorghe Brănoiu & Silvian Suditu, 2022. "The Use of Hydraulic Fracturing in Stimulation of the Oil and Gas Wells in Romania," Sustainability, MDPI, vol. 14(9), pages 1-33, May.
    14. Dariusz Knez & Mohammad Ahmad Mahmoudi Zamani, 2021. "A Review of the Geomechanics Aspects in Space Exploration," Energies, MDPI, vol. 14(22), pages 1-21, November.
    15. Dariusz Knez & Mohammad Ahmad Mahmoudi Zamani, 2021. "Empirical Formula for Dynamic Biot Coefficient of Sandstone Samples from South-West of Poland," Energies, MDPI, vol. 14(17), pages 1-17, September.

    Corrections

    All material on this site has been provided by the respective publishers and authors. You can help correct errors and omissions. When requesting a correction, please mention this item's handle: RePEc:gam:jeners:v:13:y:2020:i:24:p:6585-:d:461781. See general information about how to correct material in RePEc.

    If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.

    If CitEc recognized a bibliographic reference but did not link an item in RePEc to it, you can help with this form .

    If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your RePEc Author Service profile, as there may be some citations waiting for confirmation.

    For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: MDPI Indexing Manager (email available below). General contact details of provider: https://www.mdpi.com .

    Please note that corrections may take a couple of weeks to filter through the various RePEc services.

    IDEAS is a RePEc service. RePEc uses bibliographic data supplied by the respective publishers.