Geomechanics and Engineering

  • 제19권1호
  • /
  • Pages.49-60
  • /
  • 2019
  • /
  • 2005-307X(pISSN)
  • /
  • 2092-6219(eISSN)
테크노프레스 (Techno-Press)
권호 표지
DOI QR코드

DOI QR Code

Characteristics of EMR emitted by coal and rock with prefabricated cracks under uniaxial compression

  • Song, Dazhao (School of Civil and Resource Engineering, University of Science and Technology Beijing) ;
  • You, Qiuju (Beijing Research Center of Urban Systems Engineering) ;
  • Wang, Enyuan (School of Safety Engineering, China University of Mining and Technology) ;
  • Song, Xiaoyan (College of Applied Science and Technology, China University of Mining and Technology) ;
  • Li, Zhonghui (School of Safety Engineering, China University of Mining and Technology) ;
  • Qiu, Liming (School of Civil and Resource Engineering, University of Science and Technology Beijing) ;
  • Wang, Sida (School of Civil and Resource Engineering, University of Science and Technology Beijing)
  • 투고 : 2018.03.30
  • 심사 : 2019.09.03
  • 발행 : 2019.09.20
⟨ 이전 논문 다음 논문 ⟩

초록

Crack instability propagation during coal and rock mass failure is the main reason for electromagnetic radiation (EMR) generation. However, original cracks on coal and rock mass are hard to study, making it complex to reveal EMR laws and mechanisms. In this paper, we prefabricated cracks of different inclinations in coal and rock samples as the analogues of the native cracks, carried out uniaxial compression experiments using these coal and rock samples, explored, the effects of the prefabricated cracks on EMR laws, and verified these laws by measuring the surface potential signals. The results show that prefabricated cracks are the main factor leading to the failure of coal and rock samples. When the inclination between the prefabricated crack and axial stress is smaller, the wing cracks occur first from the two tips of the prefabricated crack and expand to shear cracks or coplanar secondary cracks whose advance directions are coplanar or nearly coplanar with the prefabricated crack's direction. The sample failure is mainly due to the composited tensile and shear destructions of the wing cracks. When the inclination becomes bigger, the wing cracks appear at the early stage, extend to the direction of the maximum principal stress, and eventually run through both ends of the sample, resulting in the sample's tensile failure. The effect of prefabricated cracks of different inclinations on electromagnetic (EM) signals is different. For samples with prefabricated cracks of smaller inclination, EMR is mainly generated due to the variable motion of free charges generated due to crushing, friction, and slippage between the crack walls. For samples with larger inclination, EMR is generated due to friction and slippage in between the crack walls as well as the charge separation caused by tensile extension at the cracks' tips before sample failure. These conclusions are further verified by the surface potential distribution during the loading process.

키워드

과제정보

연구 과제 주관 기관 : National Natural Science Foundation of China, Central Universities

참고문헌

  1. Alekseev, D.V., Egorov, P.V. and Ivanov, V.V. (1993), "Mechanisms of electrification of cracks and electromagnetic precursors of rock fracture", J. Min. Sci., 28(6), 515-519. https://doi.org/10.1007/BF00734067.
  2. Bagheripour, M.H., Rahgozar, R., Pashnesaz, H. and Malekinejad, M. (2011), "A complement to Hoek-Brown failure criterion for strength prediction in anisotropic rock", Geomech. Eng., 3(1), 61-81. http://dx.doi.org/10.12989/gae.2011.3.1.061.
  3. Cao, P., Liu, T., Pu, C. and Lin, H. (2015), "Crack propagation and coalescence of brittle rock-like specimens with pre-existing cracks in compression", Eng. Geol., 187, 113-121. https://doi.org/10.1016/j.enggeo.2014.12.010.
  4. Carpinteri, A., Lacidogna, G., Borla, O., Manuello, A. and Niccolini, G. (2012), "Electromagnetic and neutron emissions from brittle rocks failure: Experimental evidence and geological implications", Sadhana, 37(1), 59-78. https://doi.org/10.1007/s12046-012-0066-4.
  5. Chao, W., Xu, J., Zhao, X. and Wei, M. (2012), "Fractal characteristics and its application in electromagnetic radiation signals during fracturing of coal or rock", Int. J. Min. Sci. Technol., 22(2), 255-258. https://doi.org/10.1016/j.ijmst.2012.03.003.
  6. Cress, G.O., Brady, B.T. and Rowell, G.A. (1987), "Sources of electromagnetic radiation from fracture of rock samples in the laboratory", Geophys. Res. Lett., 14(4), 331-334. https://doi.org/10.1029/GL014i004p00331.
  7. Do, N.A., Dias, D., Oreste, P. and Djeran-Maigre, I. (2014), "2D numerical investigations of twin tunnel interaction", Geomech. Eng., 6(3), 263-275. http://dx.doi.org/10.12989/gae.2014.6.3.263.
  8. Frid, V., Rabinovitch, A. and Bahat, D. (2006), "Crack velocity measurement by induced electromagnetic radiation", Phys. Lett. A, 356(2), 160-163. https://doi.org/10.1016/j.physleta.2006.03.024.
  9. Fukui, K., Okubo, S. and Terashima, T. (2005), "Electromagnetic radiation from rock during uniaxial compression testing: the effects of rock characteristics and test conditions", Rock Mech. Rock Eng., 38(5), 411-423. https://doi.org/10.1007/s00603-005-0046-7.
  10. Gade, S.O., Weiss, U., Peter, M.A. and Sause, M.G.R. (2014), "Relation of electromagnetic emission and crack dynamics in epoxy resin materials", J. Nondestruct. Eval., 33(4), 711-723. https://doi.org/10.1007/s10921-014-0265-5.
  11. Greiling, R.O. and Obermeyer, H. (2010), "Natural electromagnetic radiation (EMR) and its application in structural geology and neotectonics", J. Geol. Soc. India, 75(1), 278-288. https://doi.org/10.1007/s12594-010-0015-y.
  12. Guo, Z.Q. (1989), "The model of compressed atoms and electron emission of rock fracture", Chin. J. Geophys., 32, 73-117.
  13. Hadjicontis V.M.C. (1994), "Transient electric signals prior to rock failure under uniaxial compression", Geophys. Res. Lett., 21(16), 1687-1690. https://doi.org/10.1029/94GL00694.
  14. Han, J., Huang, S., Zhao, W., Wang, S., and Deng, Y. (2018), "Study on electromagnetic radiation in crack propagation produced by fracture of rocks", Measurement, 131, 125-131. https://doi.org/10.1016/j.measurement.2018.06.067.
  15. He, X.Q. and Liu, M. (1995), Electro-magnetic Dynamics of Coal or Rock Containing Gas, University of Mining and Technology Press, Xuzhou, China.
  16. Hoxha, D., Lespinasse, M,. Sausse, J. and Homand F. (2005), "A microstructural study of natural and expermentally induced cracks in a granodiorite", Tectonophysics, 395, 99-112. https://doi.org/10.1016/j.tecto.2004.09.004.
  17. Ivanov, V.V., Egorov, P.V., Kolpakova, L.A. and Pimonov, A.G. (1988), "Crack dynamics and electromagnetic emission by loaded rock masses", Soviet Min., 24(5), 406-412. https://doi.org/10.1007/BF02498591.
  18. Krajcinovic, D. (1989), "Damage mechanics", Mech. Mater., 8(2-3), 117-197. https://doi.org/10.1016/0167-6636(89)90011-2.
  19. Krumbholz, M., Bock, M., Burchardt, S., Kelka, U. and Vollbrecht, A. (2012), "A critical discussion of the electromagnetic radiation (EMR) method to determine stress orientations within the crust", Solid Earth, 3(2), 401-414. https://doi.org/10.5194/se-3-401-2012.
  20. Kumar, A., Chauhan, V. S., Sharma, S. K., and Kumar, R. (2017), "Deformation induced electromagnetic response of soft and hard PZT under impact loading", Ferroelectrics, 510(1), 170-183. https://doi.org/10.1080/00150193.2017.1328726.
  21. Kumar, S.S., Kumar, S.A., Chauhan, V.S. and Michael, S. (2018), "Effect of low temperature on electromagnetic radiation from soft pzt sp-5a under impact loading", J. Elect. Mater., 47(10), 5930-5938. https://doi.org/10.1007/s11664-018-6464-6.
  22. Lacidogna, G., Carpinteri, A., Manuello, A., Durin, G., Schiavi, A. and Niccolini, G. and Agosto, A. (2011), "Acoustic and electromagnetic emissions as precursor phenomena in failure processes", Strain, 47(s2), 144-152. https://doi.org/10.1111/j.1475-1305.2010.00750.x.
  23. Leeman, J.R., Scuderi, M.M., Marone, C., Saffer, D.M. and Shinbrot, T. (2014), "On the origin and evolution of electrical signals during frictional stick slip in sheared granular material", J. Geophys. Res. Solid Earth, 119(5), 4253-4268. https://doi.org/10.1002/2013JB010793.
  24. Liu, X. and Wang, E. (2018), "Study on characteristics of EMR signals induced from fracture of rock samples and their application in rockburst prediction in copper mine", J. Geophys. Eng., 15(3), 909-920. https://doi.org/10.1088/1742-2140/aaa3ce.
  25. Liu, Y., Liu, Y., Wang, Y., Jin, A., Fu, J. and Cao, J. (1997), "The influencing factors and mechanisms of the electromagnetic radiation during rock fracture", Acta Seismologica Sinica, 10(4), 86-94. https://doi.org/10.1007/s11589-997-0061-8.
  26. Mori, Y., Obata, Y., Pavelka, J., Sikula, J. and Lokajicek, T. (2004), "AE Kaiser effect and electromagnetic emission in the deformation of rock sample", J. Acoust. Emission, 22, 91-101.
  27. Nardi, A. and Caputo, M. (2009), "Monitoring the mechanical stress of rocks through the electromagnetic emission produced by fracturing", Int. J. Rock Mech. Min. Sci., 46(5), 940-945. https://doi.org/10.1016/j.ijrmms.2009.01.005
  28. Nitsan, U. (1977), "Electromagnetic emission accompanying fracture of quartz-bearing rocks", Geophys. Res. Lett., 4(8), 333-336. https://doi.org/10.1029/GL004i008p00333.
  29. O'Keefe, S.G. and Thiel, D.V. (1995), "A mechanism for the production of electromagnetic radiation during fracture of brittle materials", Phys. Earth Planet. Inter., 89(1-2), 127-135. https://doi.org/10.1016/0031-9201(94)02994-M.
  30. Ogawa, T., Oike, K. and Miura, T. (1985), "Electromagnetic radiation from rocks", J. Geophys. Res. Atmosph., 90(D4), 6245-6250. https://doi.org/10.1029/JD090iD04p06245.
  31. Price, N.J, (1966), Fault and Joint Development: in Brittle and Semi-brittle Rock, Pergamon Press, Oxford, England, U.K.
  32. Qian, S., Zhang, Y., Cao, H. and Zhi, A.L. (1986), "Electromagnetic Radiation Generated by the Rock Rupture During an Underground Explosion", Acta Seismologica Sinica.
  33. Rabinovitch, A., Frid, V. and Bahat, D. (2007), "Surface oscillations-A possible source of fracture induced electromagnetic radiation", Tectonophysics, 431(1-4), 15-21. https://doi.org/10.1016/j.tecto.2006.05.027.
  34. Rabinovitch, A., Frid, V. and Bahat, D. (2017), "Directionality of electromagnetic radiation from fractures", Int. J. Fracture, 204(2), 239-244. https://doi.org/10.1007/s10704-016-0178-7.
  35. Rosen, B.W. (1964), "Tensile failure of fibrous composites", AIAA J., 2, 64-73. https://doi.org/10.2514/3.2699.
  36. Sharma, S.K., Chauhan, V.S. and Kumar, A. (2016), "Detection of electromagnetic radiation in ferroelectric ceramics for noncontact sensing applications", J. Alloys Compounds, 662, 534-540. https://doi.org/10.1016/j.jallcom.2015.12.026.
  37. Song, D., Wang, E., He, X., Jia, H., Qiu, L., Chen, P., and Wang, S. (2018), "Use of electromagnetic radiation from fractures for mining-induced stress field assessment", J. Geophys. Eng., 15(4), 1093-1103. https://doi.org/10.1088/1742-2140/aaa26d.
  38. Song, D., Wang, E., Li, Z., Qiu, L. and Xu, Z. (2017), "EMR: An effective method for monitoring and warning of rock burst hazard", Geomech. Eng., 12(1), 53-69. https://doi.org/10.12989/gae.2017.12.1.053.
  39. Song, D., Wang, E., Song, X., Jin, P. and Qiu, L. (2016), "Changes in frequency of electromagnetic radiation from loaded coal rock", Rock Mech. Rock Eng., 49(1), 291-302. https://doi.org/10.1007/s00603-015-0738-6.
  40. Wang, E., (1997), "The effect of EMR & AE during the fracture of coal containing gas and its applications", Ph.D. Dissertation, China University of Mining and Technology, Xuzhou, China.
  41. Wang, E., He, X., Li, Z. and Zhao, E. (2009), Electromagnetic Radiation Technology and Application of Coal or Rock, Science Press, Beijing, China.
  42. Yamada, T. and Oike, K. (1996), "Electromagnetic radiation phenomena before and after the 1995 Hyogo-ken Nanbu Earthquake", Earth Planets Sp., 44(4), 405-412. https://doi.org/10.4294/jpe1952.44.405.
  43. Yavorovich, L.V., Bespalko, A.A., Fedotov, P.I. and Baksht, R.B. (2016), "Electromagnetic radiation generated by acoustic excitation of rock samples", Acta Geophysica, 64(5), 1446-1461. https://doi.org/10.1515/acgeo-2016-0081.
  44. Zhu, W., Chen, W. and Shen, J. (1998), "Simulation experiment and fracture mechanism study on propagation of Echelon pattern cracks", Acta Mechanica Solida Sinica, 19, 355-360.
  45. Zweben, C. and Rosen, B.W. (1970), "A statistical theory of material strength with application to composite materials", J. Mech. Phys. Solids, 18(3), 189-206. https://doi.org/10.1016/0022-5096(70)90023-2.