Q-system (geotechnical engineering)

  1. Pages with script errors
  2. Pages using duplicate arguments in template calls
  3. Pages with OL errors
  4. Geotechnical engineering
  5. Rock mass classification


For the linguistics formalism, see Q-systems.

The Q-system for rock mass classification is developed by Barton, Lien, and Lunde[1][2][3][4][5][6][7][8][9]. It expresses the quality of the rock mass in the so-called Q-value, on which are based design and support recommendations for underground excavations.

The Q-value is determined with

\[Q=\frac{RQD}{J_n} * \frac{J_r}{J_a} * \frac{J_w}{SRF}\]

The first term RQD (Rock Quality Designation) divided by Jn (joint set number) is related to the size of the intact rock blocks in the rock mass. The second term Jr (joint roughness number) divided by Ja (joint alteration number) is related to the shear strength along the discontinuity planes and the third term Jw (joint water parameter) divided by SRF (stress reduction factor) is related to the stress environment on the intact rock blocks and discontinuities around the underground excavation.

A multiplication of the three terms results in the Q parameter, which can range between 0.00006 for an exceptionally poor to 2666 for an exceptionally good rock mass. The numerical values of the class boundaries for the different rock mass qualities are subdivisions of the Q range on a logarithmic scale.

The Q-value determines the quality of the rock mass, but the support of an underground excavation is based not only on the Q-value but is also determined by the different terms in the above equation. This leads to a very extensive list of classes for support recommendations.

References

  1. ↑ Script error
  2. ↑ Barton, N.R. (1-5 November 1976). "Recent experiences with the Q-system of tunnel support design". In Bieniawski, Z.T.. Proc. Symposium on Exploration for Rock Engineering, Johannesburg. 1. Balkema, Cape Town. pp. 107-117. ISBN 0869610899.
  3. ↑ Barton, N.R.; Lien, R.; Lunde, J. (1977). "Estimation of support requirements for underground excavations & discussion". In Fairhurst, C.; Crouch, S.L.. Proc. of 16th Symp. on Design Methods in Rock Mechanics, University of Minnesota, Minneapolis, U. S. A, 1975. American Society of Civil Engineers (ASCE), New York. pp. 163–177, 234–241. Error: Bad OL specified!.
  4. ↑ Barton, N.R. (1988). "Rock Mass Classification and Tunnel Reinforcement Selection using the Q-system". In Kirkaldie, L.. Rock Classification Systems for Engineering Purposes: ASTM Special Technical Publication 984. 1. ASTM International. pp. 59-88. doi:10.1520/STP48464S. ISBN 978-0803109889.
  5. ↑ Barton, N.R.; Grimstad, E. (1993). "Updating the Q-system for NMT". In Kompen, C.; Berg, S.L.. Proc. of the International Symposium on Sprayed Concrete - Modern Use of Wet Mix Sprayed Concrete for Underground Support, Fagernes, 1993. Norwegian Concrete Association, Oslo. pp. 163–177, 234–241. Error: Bad OL specified!.
  6. ↑ Script error
  7. ↑ Script error
  8. ↑ Script error
  9. ↑ Script error

Further reading

  • Bieniawski, Z.T. "Engineering Rock Mass Classifications", John Wiley and Sons, New York, 1989
  • Hack, H.R.G.K. (25-28 November 2002). "An evaluation of slope stability classification. Keynote Lecture.". In Dinis da Gama, C.; Ribeira e Sousa, L.. Proc. ISRM EUROCK’2002. Funchal, Madeira, Portugal: Sociedade Portuguesa de Geotecnia, Lisboa, Portugal. pp. 3–32. ISBN 972-98781-2-9.
  • Pantelidis, L (2009). "Rock slope stability assessment through rock mass classification systems", International Journal of Rock Mechanics and Mining Sciences, 46(2), (315–325).
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See also


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