Paper contribution

RMR based tunnel support

Ferenc Deák; Alex Lowson

Proceedings
EUROCK 2026
Pages
813-820
Submitted
28 January 2026
Accepted
15 June 2026
Published
12 August 2026

Summary

Abstract

For professional and unprofessinal tunnelling engineers, particularly in the early stages of a project, this study will be useful as it provides a critical assessment of what works best in the RMR rock mass classification system and how the values derived from it can be translated into the establishment of a practical rock safety system 46 years after its development (RMR89) and extensive accumulated experience. It addresses three aspects of practical tunnel design: 1) new design tables for determining the required rock protection as a function of tunnel span and rock quality; 2) the determination of tunnel cross-section shape and secondary masonry; and 3) an updated RMR grading method for practical applications. It will be briefly demonstrated how numerical modelling of tunnel design issues goes hand in hand with RMR-based estimation of rock mass properties and in-situ quality. The practical solutions presented below are the first to appear in Hungarian and are based on the experience accumulated over several decades by Lowson and Bieniawski (2013). After years of verification and use, the first author is pleased to note that the recommendations are truly connected to reality and work well. Not only the Q method guidelines can be used to establish rock support, but also the RMR. In this paper the authors updated some equations from the past and prepared an empirical solution for the time dependent stand up time and RMR time dependent degradation.

Contributors

Authors

  1. Ferenc Deák TunnelTech, Hungary
  2. Alex Lowson MottMacDonald

Index terms

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Works cited

References

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