Probabilistic analysis of three-dimensional tunnel face stability in soft rock masses using Hoek–Brown failure criterion

Jiahua Zhang, Lianyang Zhang, Weijun Wang, Daobing Zhang, Biao Zhang

Research output: Contribution to journalArticlepeer-review

4 Scopus citations

Abstract

This paper investigates tunnel face stability in soft rock masses via coupled limit and reliability analyses. Specifically, a 3D face collapse mechanism was first constructed. Then the Hoek–Brown failure criterion was introduced into the limit analysis via the tangential technique. Taking the variability of rock mass parameters and loads into consideration, a reliability model was established. The collapse pressure and failure range of tunnel faces were determined. In addition, the required factor of safety (FS) and supporting pressure under three safety levels were obtained, and the corresponding safety level graphs for support design were presented. Comparison of the obtained results with previous work demonstrates the rationality of the 3D collapse mechanism and the validity of the results. A decrease in the geological strength index, Hoek–Brown parameter mi, and uniaxial compressive strength or an increase in the disturbance factor results in a nonlinear increase of the collapse pressure and an enlargement of the failure zone. Such changes also lead to a nonlinear increase of the required support pressure under a certain safety level. By contrast, the FS does not exhibit any obvious change when these parameters vary. Therefore, when a rock mass is of poor quality or heavily disturbed, the advance support should be enlarged from upper front to right above the tunnel face. Moreover, as the safety level increases, both the required FS and supporting pressure of the tunnel face increase nonlinearly at a higher rate.

Original languageEnglish (US)
Pages (from-to)1601-1616
Number of pages16
JournalInternational Journal for Numerical and Analytical Methods in Geomechanics
Volume44
Issue number11
DOIs
StatePublished - Aug 10 2020

Keywords

  • Hoek–Brown failure criterion
  • failure probability
  • limit analysis
  • support pressure
  • three-dimensional collapse
  • tunnel face

ASJC Scopus subject areas

  • Computational Mechanics
  • Materials Science(all)
  • Geotechnical Engineering and Engineering Geology
  • Mechanics of Materials

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