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Researchers Develop Accurate Stress Updating Algorithm for Rock Mechanics and Geotechnical Engineering

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— 2 min read

A team of researchers at Beijing University of Technology has published a new report on rock mechanics and geotechnical engineering, presenting an accurate stress updating algorithm for the generalized Zhang-Zhu (GZZ) criterion. According to the study, the algorithm is an extension to the Hoek-Brown criterion and the Mogi criterion, providing a simplified approach to elasto-plastic finite element calculations. The researchers found that the introduction of mean normal stress results in a non-smooth and non-convex yield surface, which poses a challenge for updating plastic stress. To address this issue, the team proposed a novel stress updating algorithm that operates entirely in the principal stress space, avoiding numerical singularities at the intersection of yield surfaces.

Key Takeaways:

  • The generalized Zhang-Zhu (GZZ) strength criterion was proposed as an extension to the Hoek-Brown criterion and the Mogi criterion by researchers at Beijing University of Technology.
  • The introduction of mean normal stress in the GZZ criterion results in a non-smooth and non-convex yield surface, which poses a challenge for updating plastic stress.
  • The proposed stress updating algorithm operates entirely in the principal stress space, avoiding numerical singularities at the intersection of yield surfaces.
  • The algorithm is an accurate and efficient solution for updating plastic stress in the GZZ criterion, facilitating calculations using both finite element implicit and explicit algorithms.
  • The proposed method has been validated using rock true triaxial test data and semi-analytical solutions for stresses and displacement around a circular opening under the GZZ criterion.
  • The research team consisted of Lianjin Tao, Linkun Huang, Xu Zhao, Johan Clausen, Qi Zhang, Boyang Jiao, and Hehua Zhu from Beijing University of Technology.
  • The study was funded by the National Key Research And Development Program of China and the National Natural Science Foundation of China.

Statistics:

  • 17(7):4527-4538: The page range of the journal article published in the Journal of Rock Mechanics and Geotechnical Engineering.
  • 2025: The year in which the research was published.
  • 2715: The page number of the news report describing the research.
  • 4: The number of different types of stress updating defined in the proposed algorithm.
  • 2: The number of criteria that the GZZ criterion was extended from (Hoek-Brown and Mogi).
  • 10.1016/j.jrmge.2024.09.043: The digital object identifier (DOI) for the journal article.

Sources:

  • Journal of Rock Mechanics and Geotechnical Engineering, 2025, 17(7):4527-4538. (Journal of Rock Mechanics and Geotechnical Engineering - http://www.journals.elsevier.com/journal-of-rock-mechanics-and-geotechnical-en)
  • NewsRx. Research on Rock Mechanics and Geotechnical Engineering Described by Researchers at Beijing University of Technology (An exact implementation of the generalized Zhang-Zhu criterion for elasto-plastic finite element calculations). Journal of Engineering. July 28, 2025; p 2715.

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