A Unified Strength criterion for rock material

Mao Hong Yu, Yue Wen Zan, Jian Zhao, Mitsutoshi Yoshimine

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211 Citations (Scopus)


A non-linear Unified Strength criterion for rock material is presented. It is the development of the Unified Strength Theory (in: M. Jono, T. Inoue (Eds.), Mechanical Behaviour of Materials-VI (ICM-6), Pergamon, Oxford, 1991, pp. 841-846) and the modification of the Hoek-Brown strength criterion (Underground Excavations in Rock, The Institution of Mining and Metallurgy, London, 1980). The effect of intermediate principal stress on rock strength is considered in the non-linear Unified Strength criterion. The Hoek-Brown criterion is a single-shear strength criterion that forms the lower bound, and the non-linear twin-shear strength criterion forms the upper bound in the deviatoric plane. All the failure criteria ranging from the Hoek-Brown criterion (lower bound) and the non-linear twin-shear criterion (upper bound) and a series of criteria ranging between these two bounds may be introduced by the non-linear Unified Strength criterion. The theory can also be generalized to rock mass strength.

Original languageEnglish
Pages (from-to)975-989
Number of pages15
JournalInternational Journal of Rock Mechanics and Mining Sciences
Issue number8
Publication statusPublished - 1 Dec 2002
Externally publishedYes


  • Hoek-brown criterion
  • Non-linear behaviour
  • Rock material
  • Single-shear strength criterion (Mohr-Coulomb strength criterion)
  • Strength criterion
  • Twin-shear strength criterion
  • Unified strength theory

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