Rock Mechanics and Rock Engineering

, Volume 43, Issue 4, pp 403–415 | Cite as

Fracture Toughness and Fracture Roughness in Anisotropic Granitic Rocks

Original Paper

Abstract

In this paper we present an experimental approach aimed at assessing the correlation between fracture toughness (K IC) and fracture roughness of two granitic rocks (Barre and Stanstead granites) exhibiting significant fracture toughness anisotropy. Roughness values have been estimated for fractured surfaces obtained from Chevron Cracked Notch Brazilian Disc samples failed under mode I along three orthogonal planes with respect to their microstructural fabrics. There exists a clear correlation between roughness and toughness within each rock examined along the three planes. Specific orientation of micro-crack alignment could result in preferred out-of-plane propagation of the test-crack irrespective of grain-size distribution. These experimental observations reinforce the hypothesis of the existence of a link among pre-existing petrofabric anisotropy, fracture toughness, fracture roughness, and the evolution and extent of the associated induced fractures within the process zone of granitic rocks along specific directions. This study also highlights the need for employment of pre-failure and advanced post-failure diagnostic techniques in quantifying these inter-relationships.

Keywords

Fracture toughness Fracture roughness X-ray micro CT SEM Fracture process zone 

Notes

Acknowledgments

The authors wish to thank Dr. SH Cho and his associates for their assistance in the CT-scan work, Dr J. Wirth and Mr. M. Braun for their assistance with the surface scans. The research work has been partially supported by NSERC/Discovery Grant No. 341275 and NSERC/RTI Grant No. 345516.

References

  1. Backers T, Fardin N, Dresen G, Stephansson O (2003) Effect of loading rate on mode I fracture toughness, roughness and micromechanics of sandstone. Int J Rock Mech Min Sci 40:425–433CrossRefGoogle Scholar
  2. Grasselli G (2001) Shear strength of rock joints based on quantified surface description. Ph.D. thesis, Swiss Federal Institute of Technology (EPFL), Lausanne, Switzerland, 125 pGoogle Scholar
  3. Grasselli G (2006) Manuel Rocha Medal recipient—Shear strength of rock joints based on quantified surface description. Rock Mech Rock Eng 39:295–314CrossRefGoogle Scholar
  4. Grasselli G, Wirth J, Egger P (2002) Quantitative three-dimensional description of a rough surface and parameter evolution with shearing. Int J Rock Mech Min Sci 39:789–800CrossRefGoogle Scholar
  5. Hoagland RG, Hahn GT, Rosenfiield AR (1973) Influence of microstructure on fracture propagation in rock. Rock Mech 5:77–106CrossRefGoogle Scholar
  6. Iqbal N, Mohanty B (2006) Experimental calibration of stress intensity factors of the ISRM suggested cracked chevron-notched Brazilian disc specimen used for determination of mode-I fracture toughness. Int J Rock Mech Min Sci 43:1270–1276CrossRefGoogle Scholar
  7. ISRM (1995) Suggested methods for the determining mode I fracture toughness using cracked chevron notched Brazilian disc (CCNBD) specimens. Int J Rock Mech Min Sci Geomech Abstr 32:57–64CrossRefGoogle Scholar
  8. Issa MA, Issa MA, Islam MS, Chudnovsky A (2003) Fractal dimension—a measure of fracture roughness and toughness of concrete. Eng Fract Mech 70:125–137CrossRefGoogle Scholar
  9. Labuz JF, Shah SP, Dowding CH (1987) The fracture process zone in granite: evidence and effect. Int J Rock Mech Geomech Abstr 24(4):235–246CrossRefGoogle Scholar
  10. Lange DA, Jennings HM, Shah SP (1993) Relationship between fracture surface-roughness and fracture-behavior of cement paste and mortar. J Am Ceram Soc 76:589–597CrossRefGoogle Scholar
  11. Launeau P, Robin PYF (1996) Fabric analysis using the intercept method. Tectonophysics 267:91–119CrossRefGoogle Scholar
  12. Nasseri MHB, Mohanty B (2008) Fracture toughness anisotropy in granitic rocks. Int J Rock Mech Min Sci 45:167–193CrossRefGoogle Scholar
  13. Nasseri MHB, Mohanty B, Robin PYF (2005) Characterization of microstructures and fracture toughness in five granitic rocks. Int J Rock Mech Min Sci 42:450–460CrossRefGoogle Scholar
  14. Nasseri MHB, Mohanty B, Young RP (2006) Fracture toughness measurements and acoustic emission activity in brittle rocks. Pure Appl Geophys 163:917–945CrossRefGoogle Scholar
  15. Ouchterlony F (1980) Review of fracture toughness testing of rocks. DS 1980 15, Swed Detoic Res Found StockholmGoogle Scholar
  16. Wirth J (2002) Rapid modeling. Hanser, Munich, p 220Google Scholar
  17. Zang A, Christian Wagner F (2000) Fracture process zone in granite. JGR 105(B10):23651–23661CrossRefGoogle Scholar

Copyright information

© Springer-Verlag 2009

Authors and Affiliations

  1. 1.Department of Civil Engineering, Lassonde InstituteUniversity of TorontoTorontoCanada

Personalised recommendations