Advertisement

Different bedding loaded coal mechanics properties and acoustic emission

  • Jiajia LiuEmail author
  • Ming YangEmail author
  • Dan Wang
  • Junhao Zhang
Original Article

Abstract

Using TAW-2000KN electro-hydraulic servo rock press machines and the American Physical Acoustics Company’s SH-II acoustic emission systems, experimental studies began to address the mechanical properties in different beddings of loaded coal and the related acoustic emission characteristics, established based on the acoustic emission damage model, and verify the model. The results show that the mechanical properties of different coal sample beddings are distinctive, with maximum uniaxial compressive strength and elastic modulus of vertical stratification of coal samples and the minimum Poisson’s ratio. Thus, the minimum uniaxial compressive strength and elastic modulus of oblique bedding coal samples along with the maximum Poisson’s ratio in the processes of loading result in different bedding coal samples having different stress–strain curves, especially when different bedding coal samples experience the stages of fissure compression, elastic deformation, plastic deformation and instability and destruction. In addition, the displacement proportions of each stage of the loading process have relatively obvious differences: the loading times of vertical, parallel and oblique bedding coal are 495, 382 and 331 s, respectively, and their acoustic emission mutation points of peak stress are approximately 60, 41 and 33%, respectively. Thus, we can use the mutation point as precursor information to estimate the damage intensity in different bedding seams. The theoretical and experimental stress–strain curves obtained by the coal damage model are basically identical, verifying the reliability of the model and reflecting the feasibility of acoustic emission technology in the study of coal damage. The results can effectively forecast coal and gas outburst hazard in coal mines, especially highly gassy and outburst mines. It can also make comprehensive predictions for flooding accidents, roof fall accidents and other disasters, and provide valuable evacuation time for underground coal mine workers. The results are of great scientific significance in safeguarding the safety of coal mines.

Keywords

Different bedding Mechanical properties Stress–strain Acoustic emission 

Notes

Acknowledgements

This work was supported by the National Natural Science Foundation of China (51604101; 51704099; 51734007), the State Key Laboratory Cultivation Base for Gas Geology and Gas Control (Henan Polytechnic University) (WS2017B06), the Doctoral Fund of Henan Polytechnic University (Grant no. B2018-59), and the Open Research Fund of State and Local Joint Engineering Laboratory for Gas Drainage & Ground Control of Deep Mines (Henan Polytechnic University) (G201608).

References

  1. Bi J, Su X (2001) The relation between cleat frequency and coal rank. J China Coal Soc 26(4):346–349 (in Chinese) Google Scholar
  2. Cao S, Liu Y, Zhang L (2007) Study on characteristics of acoustic emission in outburst coal. Chin J Rock Mech Eng 26(S1):2794–2799 (in Chinese) Google Scholar
  3. Chen J, Qin Y, Song Q et al (2003) Coupling relationship between direction of coalbed cleat and methane drainage effect and its prediction model. J China Univ Min Technol 32(3):223–226 (in Chinese) Google Scholar
  4. Chen H, Cheng Y et al (2014) Permeability distribution characteristics of protected coal seams during unloading of the coal body. Int J Rock Mech Min Sci 71:105–116Google Scholar
  5. Feng X, Zhang N, Zheng X et al (2015) Strength restoration of cracked sandstone and coal under a uniaxial compression test and correlated damage source location based on acoustic emissions. PLoS One 12:1–20Google Scholar
  6. Gao B, Li H, Li H et al (2015) Coustic emission and fractal characteristics of aturated coal samples in the failure process. J Min Saf Eng 4:665–670 (in Chinese) Google Scholar
  7. Gong Y, Song Z, He M et al (2017) Rrecursory waves and eigenfrequencies identified from acoustic emission data based on singular spectrum analysis and laboratory rock-burst experiments. Int J Rock Mech Min Sci 91:155–169Google Scholar
  8. He J, Pan J, Wang A (2014) Acoustic emission characteristics of coal specimen under triaxial cyclic loading and unloading. J Coal China Soc 1:84–90 (in Chinese) Google Scholar
  9. Hou P, Gao F, Ju Y et al (2016) Experimental investigation on the failure and acoustic emission characteristics of shale,sandstone and coal under gas fracturing. J Nat Gas Sci Eng 35:211–223CrossRefGoogle Scholar
  10. Huang X (2012) Experimental study on influence of structural anisot-ropy of coal upon gas permeability. Min Saf Environ Protect 39(2):1–3 (in Chinese) Google Scholar
  11. Klawitter M, Esterle J, Collins S (2015) A study of hardness and fracture propagation in coal. Int J Rock Mech Min Sci 76:237–242Google Scholar
  12. Koenig R, Stubbs P (1986) Interference testing of a coalbed methane reservoir. In: Proceedings of the SPE unconventional gas technology symposiumGoogle Scholar
  13. Kong X, Wang E, Hu S,et al (2015) Critical slowing down on acoustic emission characteristics of coal containing methane. J Nat Gas Sci Eng 24:156–165CrossRefGoogle Scholar
  14. Li H, Shimada S, Zhang M (2004) Anisotropy of gas permeability associated with cleat pattern in a coal seam of the Kushiro coalfield in Japan. Environ Geol 47:45–50CrossRefGoogle Scholar
  15. Liang Y, Cheng Y, Zou Q et al (2017) Response characteristics of coal subjected to hydraulic fracturing: An evaluation based on real-time monitoring of borehole strain and acoustic emission. J Nat Gas Sci Eng 38:402–411CrossRefGoogle Scholar
  16. Li H, Kang L, Xu Z et al (2014) Precursor information analysis on acoustic emission of coal with different outburst proneness. J Coal China Soc 39(2):384–388 (in Chinese) Google Scholar
  17. Li B, Li N, Wang E, Li X, Niu Y, Zhang X (2017) Characteristics of coal mining microseismic and blasting signals at Qianqiu coal mine. Environ Earth Sci 76:705–722CrossRefGoogle Scholar
  18. Liu J et al (2011) Evolution of coal permeability from stress-controlled to displacement-controlled swelling conditions. Fuel 90(10):2987–2997CrossRefGoogle Scholar
  19. Luo H, Pan Y, Zhao Y et al (2015) Experimental study on acoustocharge precursory information of coal containing gas during loading failure process. J Coal China Soc 3:548–554 (in Chinese) Google Scholar
  20. Majewska Z, Majewski S, Zietek J (2013) Swelling and acoustic emission behavior of unconfined and confined coal during sorption of CO2. Int J Coal Geol 116/117:17–25CrossRefGoogle Scholar
  21. Pan R, Cheng Y, Dong J, Chen H (2014) Research on permeability characteristics of layered natural coal under different loading and unloading. J China Coal Soc 3:473–477 (in Chinese) Google Scholar
  22. Shen R, Yang S, Deng X (2014) Analysis on water affected to mechanical property and acoustic-electricity characteristics of coal sample. Coal Sci Technol 11:11–13 (in Chinese) Google Scholar
  23. Shkuratnik VL, Filimonov L, Kuchurin SV (2005) Regularities of acoustic emission in coal samples under triaxial compression. J Min Sci 41(1):44–52CrossRefGoogle Scholar
  24. Su C, Guo B, Tang X (2014) Research on acoustic emission characteristics of Zhangcun coal samples in two sizes subject to uniaxial compression. J China Coal Soc S1:12–18 (in Chinese) Google Scholar
  25. Vinnikov VA, Voznesenskii AS, Ustinov KB et al (2010) Theoretical models of acoustic emission in rock with different heating regimes. J Appl Mech Tech Phys 51(1):84–88CrossRefGoogle Scholar
  26. Wang S, Elsworth D, Liu J (2011) Permeability evolution in fractured coal: the roles of fracture geometry and water-content. Int J Coal Geol 87:13–25CrossRefGoogle Scholar
  27. Wang S, Elsworth D, Liu J (2013) Permeability evolution during progressive deformation of intact coal and implications for instability in underground coal seams. Int J Rock Mech Min Sci 58:34–45Google Scholar
  28. Wang H et al (2015) Relationship between macro-fracture density, P-wave velocity, and permeability of coal. J Appl Geophys 117:111–117CrossRefGoogle Scholar
  29. Wen Z, Wang X, Chen L et al (2017) Size effect on acoustic emission characteristics of coal rock damage evolution. Adv Mater Sci Eng 1:1–9Google Scholar
  30. Xiao F, Shen Z, Liu G et al (2014) Relationship between hysteresis loop and elastoplastic strain energy during cyclic loading and unloading. Chin J Rock Mech Eng 9:1791–1797 (in Chinese) Google Scholar
  31. Xiao F, Liu G, Shen Z (2015) Research on effective elastic energy release rate of taoshan #90 coal seam. Chin J Rock Mech Eng S2:4216–4225 (in Chinese) Google Scholar
  32. Xiao F, Liu G, Shen Z et al (2016) Energy conversion and acoustic emission characteristics of coal sample under cyclic loading. Chin J Rock Mech Eng 35(1):1–11 (in Chinese) Google Scholar
  33. Xu J, Geng J, Peng S et al (2015) Acoustic emission characteristics of coal and gas outburst under different moisture contents. J China Coal Soc 5:1047–1054 (in Chinese) Google Scholar
  34. Yu Y, Wang L, Zhao N (2006) Effect of impulse and bedding on impact toughness of coal. J Liaoning Tech Univ 25(6):842–844 (in Chinese) Google Scholar
  35. Zhang Z, Liu J, Wang L (2013) Mechanical properties and acoustic emission characteristics of coal under direct tensile loading conditions. J Coal China Soc 6:960–965 (in Chinese) Google Scholar
  36. Zhang C et al (2015) Evaluating pressure-relief mining performances based on surface gas venthole extraction data in longwall coal mines. J Nat Gas Sci Eng 24:431–440CrossRefGoogle Scholar
  37. Zhao H, Yang S, Zhong S (2010) Analysis on the AE characteristics of outburst-hazardous coal under different loading mode. J Min Saf Eng 4:543–547Google Scholar
  38. Zhao H, Liu C, Yetilmezsoy K, Zhang B, Zhang S (2017) Fractural structure of thick hard roof stratum using long beam theory and numerical modeling. Environ Earth Sci 76:738–751CrossRefGoogle Scholar
  39. Zuo J, Pei J, Liu J (2011) Investigation on acoustic emission behavior and its time-space evolution mechanism in failure process of coal-rock combined body. Chin J Rock Mech Eng 30(8):1564–1570 (in Chinese) Google Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.State Key Laboratory Cultivation Base for Gas Geology and Gas ControlHenan Polytechnic UniversityJiaozuoChina
  2. 2.State and Local Joint Engineering Laboratory for Gas Drainage and Ground Control of Deep MinesHenan Polytechnic UniversityJiaozuoChina
  3. 3.School of Safety Science and EngineeringHenan Polytechnic UniversityJiaozuoChina
  4. 4.School of Safety EngineeringHeilongjiang University of Science and TechnologyHarbinChina

Personalised recommendations