Paper contribution

Applicability of the Stability Graph Method for Designing Large Caverns in Rock

César Torrero; Luis Jordá; Salvador Senent

Proceedings
EUROCK 2026
Pages
719-724
Submitted
28 January 2026
Accepted
15 June 2026
Published
12 August 2026

Summary

Abstract

Rock engineering classification systems have traditionally been widely used in the preliminary design of tunnels, mines and underground caverns excavated in rock. These systems constitute standardized empirical approaches based on field data and accumulated experience, enabling rapid and practical assessment of rock mass conditions. In particular, design charts derived from these classifications —such as the Q-system or the RMR—are commonly applied to estimate the maximum unsupported span and support requirements. In the case of civil engineering caverns, these aspects are especially critical due to the large dimensions of such openings. The stability graph method, introduced by Mathews in 1980, integrates the strengths of the Q classification with the introduction of the hydraulic radius as the design shape factor and the implicit consideration of the critical joint and failure modes. However, the original method was developed for mining stopes under non-entry conditions and short design life spans. This paper examines the applicability of the stability graph method to civil engineering caverns. Aspects such as shape, construction procedure, rock mass conditions or support demands are analysed, evaluating their consistency with the original assumptions and design principles of the method. The shortcomings of the classical mining method applied to civil caverns are exposed such as the requirement for long-term stability in civil caverns versus the short exposure of mining stopes, the different support system typologies, roof geometry, or variations in stress conditions — particularly in shallow and isolated caverns. Despite these limitations, the stability graph method has proven to be a valuable complementary tool for the preliminary design of large-span underground openings.

Contributors

Authors

  1. César Torrero Universidad Politécnica de Madrid, Spain
  2. Luis Jordá Universidad Politécnica de Madrid, Spain
  3. Salvador Senent Universidad Politécnica de Madrid, Spain

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References

  1. Barton N, By, TL, Chryssanthakis P, Tunbridge L, Kristiansen J, Løset F, Bhasin RK Westerdahl H, Vik, G (1994) Predicted and Measured Performance of the 62 m Span Norwegian Olympic Ice Hockey Cavern at Gjøvik. Int. J. Rock Mech. Min. Sci. &Geomech. Abstr. Vol. 31, No. 6, pp. 617–641.
  2. Barton N, Lien R, Lunde J (1974) Engineering Classification of Rock Masses for the Design of Tunnel Support. Rock Mech (6): 189–236.
  3. Bieniawski ZT (1973) Engineering Classification of Jointed Rock Masses. Civ. Eng. S. Afr. (15): 335–343.
  4. Mathews KE, Hoek E, Wyllie DC, Stewart SBV (1980) Prediction of stable excavation spans formining at depths bellow 1000 m in hard rock. Canada Center for Mineral and Energy Technology. Golder Associates.
  5. Potvin Y (1988) Empirical Open Stope Design in Canada. Dept. Mining and Mineral Processing, University of British Columbia, Canada.
  6. Nickson SD (1992) Cable support guidelines for underground hard rock mine operations. University of British Columbia, Canada.
  7. Winn K, Wong LNI, Alejano, LR (2018)Multi-approach stability analyses of large caverns excavated in low-angled bedded sedimentary rock masses in Singapore.
  8. Xingdong Z, Lei D, Shujing, Z (2020) Stability analysis of underground water-sealed oil storage caverns in China： A case study.
  9. Barton N (2014) Lessons learned using empirical methods applied in mining. 1st. Int. Conf. on Applied Empirical Methods in Mining. Lima, Peru. January 2014.
  10. Geotechnical Engineering Office (2018) Guide to Cavern Engineering. Geoguide 4. Civil Engineering and Development Department. The Government of the Hong Kong. Special Administrative Region.
  11. Barton N (1989) Cavern Design for Honk Kong rocks. Proceedings of the Seminar Rock Cavern, Honk Kong, December 1989.
  12. Alonso A, Jambrina I (1999) Excavación de la caverna de cental del salto hidroeléctrico de Ricobayo II. Aspectos geotécnicos y constructivos. IngeoTúneles 2.
  13. Potvin Y, Milne, D (1992) Empirical cable bolt support design. International Symposium on Rock Mechanics.
  14. Lauffer H (1958) Gebirgsklassifizierung für den Stollenbau. Geologie und Bauwesen. 24 (1): 46–51.
  15. Suorineni T (2010) The stability graph after three decades in use: Experiences and the way forward. Nazarbayev University.
  16. Cecil OS, (1970)Correlations of Rock Bolt - Shotcrete Support and Rock Quality Parameters in Scandinavian Tunnels. Ph.D. Thesis, University of Illinois, Urbana, pp. 1-414.
  17. Bhatkar T, Usmani A, Mandal A, Nanda, A (2018) Wedge failure analysis and remedial measures in large unlined rock cavern: a case study.