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The Q-Slope Method for Rock Slope Engineering

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Abstract

Q-slope is an empirical rock slope engineering method for assessing the stability of excavated rock slopes in the field. Intended for use in reinforcement-free road or railway cuttings or in opencast mines, Q-slope allows geotechnical engineers to make potential adjustments to slope angles as rock mass conditions become apparent during construction. Through case studies across Asia, Australia, Central America, and Europe, a simple correlation between Q-slope and long-term stable slopes was established. Q-slope is designed such that it suggests stable, maintenance-free bench-face slope angles of, for instance, 40°–45°, 60°–65°, and 80°–85° with respective Q-slope values of approximately 0.1, 1.0, and 10. Q-slope was developed by supplementing the Q-system which has been extensively used for characterizing rock exposures, drill-core, and tunnels under construction for the last 40 years. The Q′ parameters (RQD, J n, J a, and J r) remain unchanged in Q-slope. However, a new method for applying J r/J a ratios to both sides of potential wedges is used, with relative orientation weightings for each side. The term J w, which is now termed J wice, takes into account long-term exposure to various climatic and environmental conditions such as intense erosive rainfall and ice-wedging effects. Slope-relevant SRF categories for slope surface conditions, stress-strength ratios, and major discontinuities such as faults, weakness zones, or joint swarms have also been incorporated. This paper discusses the applicability of the Q-slope method to slopes ranging from less than 5 m to more than 250 m in height in both civil and mining engineering projects.

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(courtesy of Panama Canal Authority, Barton and Bar 2015)

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Abbreviations

RQD:

Rock quality designation

J n :

Joint sets number

J r :

Joint roughness number

J a :

Joint alteration number

J wice :

Environmental and geological condition number

SRFslope :

Three strength reduction factors a, b, and c

SRFa :

Physical condition number

SRFb :

Stress and strength number

SRFc :

Major discontinuity number

O-factor:

Orientation factor for the ratio J r/J a

References

  • Bar N, Barton N (2016) Empirical slope design for hard and soft rocks using Q-slope. In: Proceedings of the 50th US rock mechanics/geomechanics symposium, ARMA 2016, Houston, 26–29 June 2016. ARMA16-384

  • Bar N, Barton N, Ryan CA (2016) Application of the Q-slope method to highly weathered and saprolitic rocks in Far North Queensland. In: Ulusay R et al (eds) Rock mechanics and rock engineering: from the past to the future; Proceedings of the ISRM international symposium, Eurock 2016, Cappadocia, 29–31 August 2016, pp 585–590

  • Barton N (1973) Review of a new shear-strength criterion for rock joints. Eng Geol 7(4):287–332

    Article  Google Scholar 

  • Barton N, Bar N (2015) Introducing the Q-slope method and its intended use within civil and mining engineering projects. In: Schubert W, Kluckner A (eds) Future development of rock mechanics; Proceedings of the ISRM regional symposium, Eurock 2015 and 64th geomechanics colloquium, Salzburg, 7–10 October 2015, pp 157–162

  • Barton N, Grimstad E (2014) Forty years with the Q-system in Norway and abroad, vol 4.1–4.25. Fjellsprengningsteknikk, Bergmekanikk, Geoteknikk, NFF, Oslo

    Google Scholar 

  • Barton N, Quadros E (2015) Anisotropy is everywhere, to see, to measure and to model. Rock Mech Rock Eng 48:1323–1339

    Article  Google Scholar 

  • Barton N, Lien R, Lunde J (1974) Engineering classification of rock masses for the design of tunnel support. Rock Mech 6:189–236

    Article  Google Scholar 

  • Barton N, Bandis S, Bakhtar K (1985) Strength, deformation and conductivity coupling of rock joints. Int J Rock Mech Min Sci Geomech Abstr 22(3):121–140

    Article  Google Scholar 

  • Bieniawski ZT (1976) Rock mass classification in rock engineering. In: Bieniawski ZT (ed) Exploration for rock engineering; Proceedings of the symposium, Cape Town, Balkema, pp 97–106

  • Bieniawski ZT (1989) Engineering rock mass classifications: a complete manual for engineers and geologists in mining, civil, and petroleum engineering. Wiley, New York, p 272p

    Google Scholar 

  • Deere DU (1963) Technical description of rock cores for engineering purposes. Felsmechanik und Ingenieurgeologie (Rock Mech Eng Geol) 1:16–22

    Google Scholar 

  • Deere DU, Hendron AJ, Patton F, Cording EJ (1967) Design of surface and near surface excavations in rock. In: Fairhust C (ed) Proceedings of the 8th U.S. symposium on rock mechanics: failure and breakage of rock, AIME, New York, pp 237–302

  • Hutchinson DJ, Diederichs MS (1996) Cable bolting in underground mines. Bitech, Vancouver

    Google Scholar 

  • Laubscher DH (1977) Geomechanics classification of jointed rock masses—mining applications. Trans Inst Min Met Sect A Min Ind 93:A1–A8

    Google Scholar 

  • Laubscher DH, Jakubec J (2001) The MRMR rock mass classification for jointed rock masses. In: Hustrulid A, Bullock C (eds) Underground mining methods: engineering fundamentals and international case studies, New York, AIME, pp 474–481

  • Romana M (1985) New adjustment ratings for application of Bieniawski classification to slopes. In: Proceedings of the ISRM international symposium on role of rock mechanics in excavations for mining and civil works, Zacatecas, pp 49–53

  • Romana M (1995) The geomechanical classification SMR for slope correction. In: Proceedings of the 8th ISRM congress on rock mechanics, vol 3, Tokyo, 25–29 September 1995, pp 1085–1092

  • Sullivan TD (2013) Global slope performance index. In Dight PM (ed) Proceedings of slope stability 2013, Brisbane, 25–27 September 2013, pp 55–80

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Acknowledgments

The authors sincerely thank Cameron Ryan (Australia), Simon Thomas (Papua New Guinea), and Luis Jorda-Bordehore (Spain) for their case study contributions.

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Authors and Affiliations

  1. Gecko Geotechnics Pty Ltd, P.O. Box 14226, Mt Sheridan, QLD, 4868, Australia

    Neil Bar

  2. Nick Barton & Associates, Fjordveien 65c, Høvik, 1363, Oslo, Norway

    Nick Barton

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  1. Neil Bar
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Correspondence to Neil Bar.

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Bar, N., Barton, N. The Q-Slope Method for Rock Slope Engineering. Rock Mech Rock Eng 50, 3307–3322 (2017). https://doi.org/10.1007/s00603-017-1305-0

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  • DOI: https://doi.org/10.1007/s00603-017-1305-0

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