DOI QR코드

DOI QR Code

A new rock brittleness index on the basis of punch penetration test data

  • Ghadernejad, Saleh (School of Mining Engineering, University of Tehran) ;
  • Nejati, Hamid Reza (Rock Mechanics Division, School of Engineering, Tarbiat Modares University) ;
  • Yagiz, Saffet (School of Mining and Geosciences, Nazarbayev University)
  • 투고 : 2019.11.09
  • 심사 : 2020.04.07
  • 발행 : 2020.05.25

초록

Brittleness is one of the most important properties of rock which has a major impact not only on the failure process of intact rock but also on the response of rock mass to tunneling and mining projects. Due to the lack of a universally accepted definition of rock brittleness, a wide range of methods, including direct and indirect methods, have been developed for its measurement. Measuring rock brittleness by direct methods requires special equipment which may lead to financial inconveniences and is usually unavailable in most of rock mechanic laboratories. Accordingly, this study aimed to develop a new strength-based index for predicting rock brittleness based on the obtained base form. To this end, an innovative algorithm was developed in Matlab environment. The utilized algorithm finds the optimal index based on the open access dataset including the results of punch penetration test (PPT), uniaxial compressive and Brazilian tensile strength. Validation of proposed index was checked by the coefficient of determination (R2), the root mean square error (RMSE), and also the variance for account (VAF). The results indicated that among the different brittleness indices, the suggested equation is the most accurate one, since it has the optimal R2, RMSE and VAF as 0.912, 3.47 and 89.8%, respectively. It could finally be concluded that, using the proposed brittleness index, rock brittleness can be reliably predicted with a high level of accuracy.

키워드

과제정보

The authors would like to thank the students and staff at the Earth Mechanics Institute, Colorado School of Mines, too numerous to mention, whose work over the last couple of decades has led to the currently existing rock test database.

참고문헌

  1. Akinbinu, V.A. (2016), "Class I and Class II rocks: Implication of self-sustaining fracturing in brittle compression", Geotech. Geol. Eng., 34, 877-887. https://doi.org/10.1007/s10706-016-0011-0.
  2. Altindag, R. (2002), "The evaluation of rock brittleness concept on rotary blast hole drills", J. S. Afr. Inst. Min. Metall., 102, 61-66.
  3. Altindag, R. (2003), "Correlation of specific energy with rock brittleness concepts on rock cutting", J. S. Afr. Inst. Min. Metall., 103(3), 163-171.
  4. Altindag, R. (2010), "Assessment of some brittleness indexes in rock-drilling efficiency", Rock Mech. Rock Eng., 43, 361-370. https://doi.org/10.1007/s00603-009-0057-x.
  5. ASTM D4543 (1995), Standard Practices for Preparing Rock Core as Cylindrical Test Specimens and Verifying Conformance to Dimensional and Shape Tolerances, ASTM International, Pennsylvania, U.S.A.
  6. Atici, U. and Ersoy, A. (2009), "Correlation of specific energy of cutting saws and drilling bits with rock brittleness and destruction energy", J. Mater. Process. Technol., 209, 2602-2612. https://doi.org/10.1016/j.jmatprotec.2008.06.004.
  7. Bieniawski, Z.T. (1967), "Mechanism of brittle fracture of rocks", Int. J. Rock Mech. Min. Sci., 4, 395-406. https://doi.org/10.1016/0148-9062(67)90030-7.
  8. Chen, G., Li, T., Wang, W., Guo, F. and Yin, H. (2017), "Characterization of the brittleness of hard rock at different temperatures using uniaxial compression tests", Geomech. Eng., 13(1), 63-77. https://doi.org/10.12989/gae.2017.13.1.063.
  9. Goktan, R.M. (1991), "Brittleness and micro-scale rock cutting efficiency", Int. J. Min. Sci. Technol., 13(3), 237-241. https://doi.org/10.1016/0167-9031(91)90339-E.
  10. Goktan, R.M. and Yilmaz, N.G. (2005), "A new methodology for the analysis of the relationship between rock brittleness index and drag pick cutting efficiency", J. S. Afr. Inst. Min. Metall., 105(10), 727-734.
  11. Gong, Q.M. and Zhao, J. (2007), "Influence of rock brittleness on TBM penetration rate in Singapore granite", Tunn. Undergr. Sp. Technol., 22(3), 317-324. https://doi.org/10.1016/j.tust.2006.07.004.
  12. Haeri, H. and Sarfarazi, V. (2017), "The effect of micro pore on the characteristics of crack tip plastic zone in concrete", Comput. Concrete, 17(1), 107-127. http://doi.org/10.12989/cac.2016.17.1.107.
  13. Haeri, H., Sarfarazi, V., Shemirani, A.B. and Zhu, Z. (2018), "Direct shear testing of brittle material samples with non-persistent cracks", Geomech. Eng., 15(4), 927-935. https://doi.org/10.12989/gae.2018.15.4.927.
  14. Hajiabdolmajid, V. and Kaiser, P. (2003), "Brittleness of rock and stability assessment in hard rock tunneling", Tunn. Undergr. Sp. Technol., 18, 35-48. https://doi.org/10.1016/S0886-7798(02)00100-1.
  15. Heidari, M., Khanlari, G.R., Torabi-Kaveh, M., Kargarian, S. and Saneie, S. (2014), "Effect of porosity on rock brittleness", Rock Mech. Rock Eng., 47, 785-790. https://doi.org/10.1007/s00603-013-0400-0.
  16. Hetenyi, M. (1966), Handbook of Experimental Stress Analysis, John Wiley & Sons Publication, New York, U.S.A.
  17. Hucka, V. and Das, B. (1974), "Brittleness determination of rocks by different methods", Int. J. Rock. Mech. Min. Sci. Geomech. Abstr., 11, 389-392. https://doi.org/10.1016/0148-9062(74)91109-7.
  18. Kahraman, S. (2002), "Correlation of TBM and drilling machine performances with rock brittleness", Eng. Geol., 65(4), 269-283. https://doi.org/10.1016/S0013-7952(01)00137-5.
  19. Kahraman, S., Toraman, O.Y. and Cayirli, S. (2018), "Predicting the strength and brittleness of rocks from a crushability index", Bull. Eng. Geol. Environ., 77(4), 1639-1645. https://doi.org/10.1007/s10064-017-1012-9.
  20. Khandelwal, M. and Armaghani, D.J. (2016), "Prediction of drillability of rocks with strength using a hybrid GA-ANN technique", Geotech. Geol. Eng., 34(2), 605-620. https://doi.org/10.1007/s10706-015-9970-9.
  21. Ko, T.Y., Kim, T.K., Son, Y. and Jeon, S. (2016), "Effect of geomechanical properties on cerchar abrasivity index (CAI) and its application to TBM tunneling", Tunn. Undergr. Sp. Technol., 57, 99-111. https://doi.org/10.1016/j.tust.2016.02.006.
  22. Meng, F., Zhou, H., Zhang, C., Xu, R. and Lu, J. (2015), "Evaluation methodology of brittleness of rock based on post-peak stress-strain curves", Rock Mech. Rock Eng., 48(5), 1787-1805. https://doi.org/10.1007/s00603-014-0694-6.
  23. Mikaeil, R., Ataei, M., Ghadernejad, S. and Sadegheslam, G. (2014), "Predicting the relationship between system vibration with rock brittleness indexes in rock sawing process", Arch. Min. Sci., 59(1), 139-153. https://doi.org/10.2478/amsc-2014-0010
  24. Mikaeil, R., Ghadernejad, S., Ataei, M., Esmailvandi, M. and Daneshvar, A. (2017), "Investigating the relationship between various brittleness indexes with specific ampere draw in rock sawing process", Int. J. Min. Geo-eng., 51(2), 125-132. http://doi.org/10.22059/ijmge.2017.214404.594626.
  25. Mikaeil, R., Zare Naghadehi, M. and Ghadernejad, S. (2018), "An extended multifactorial fuzzy prediction of hard rock TBM penetrability", Geotech. Geol. Eng., 36(3), 1779-1804. https://doi.org/10.1007/s10706-017-0432-4.
  26. Morley, A. (1944), Strength of Materials, Longman, London, U.K.
  27. Nejati, H.R. and Ghazvinian, A. (2014), "Brittleness effect on rock fatigue damage evolution", Rock Mech. Rock Eng., 47(5), 1839-1848. https://doi.org/10.1007/s00603-013-0486-4.
  28. Nejati, H.R. and Moosavi, S.A. (2017), "A new brittleness index for estimation of rock fracture toughness", J. Min. Environ., 8(1), 83-91. http://doi.org/10.22044/jme.2016.579.
  29. Obert, L. and Duvall, W.I. (1967), Rock Mechanics and the Design of Structures in Rock, Wiley, New York, U.S.A.
  30. Ramsay, J.G. (1967), Folding and Fracturing of Rocks, McGraw-Hill, London, U.K.
  31. Singh, S.P. (1986), "Brittleness and the mechanical winning of coal", Int. J. Min. Sci. Technol., 3(3), 173-180. https://doi.org/10.1016/S0167-9031(86)90305-1.
  32. Yagiz, S. (2009), "Assessment of brittleness using rock strength and density with punch penetration test", Tunn. Undergr. Sp. Technol., 24(1), 66-74. https://doi.org/10.1016/j.tust.2008.04.002.
  33. Yagiz, S. (2017), "New equations for predicting the field penetration index of tunnel boring machines in fractured rock mass", Arab. J. Geosci., 10, 1-13. https://doi.org/10.1007/s12517-016-2811-1.
  34. Yaitli, N.E., Bayram, F., Unver, B. and Ozcelik, Y. (2012), "Numerical modelling of circular sawing system using discrete element method", Int. J. Rock Mech. Min. Sci., 55, 86-96. https://doi.org/10.1016/j.ijrmms.2012.06.006.