Modeling of brittle failure based on a Hoek & Brown yield criterion: parametric studies and constitutive validation

F Marinelli, N. Zalamea, Gregor Vilhar, S. Brasile, G. Cammarata, Ronald Brinkgreve

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Hoek & Brown (HB) failure criteria have been employed over the past decades in common engineering applications due to their extended capability to capture the non-linear yielding of different types of rocks. Often implemented within a perfect plastic framework, this constitutive approach is here enhanced by introducing a softening rule to simulate the post-peak behaviour of rocks in the brittle regime. For this purpose, the degradation of the material properties has been expressed as a function of an internal variable (i.e., the cumulated value of deviatoric plastic strains) which allows one to simulate the rock failure resulting from dilating shearing. Furthermore, to accurately describe the non-linear dilatancy after the peak, the same hyperbolic trend has been applied also to the material properties governing the expression of the plastic potential. The performance of these constitutive equations has been inspected through parametric analyses to emphasize the role of the softening parameters at material point level, as well as to study the strain localization potential of the Hoek & Brown model with Softening (HBS). As a further validation, the shear band angles predicted with the theory have been compared by performing the same tests with finite element code PLAXIS 2D, thus confirming the model capability to simulate failure mechanisms within a strain localization regime.
Original languageEnglish
Title of host publicationProceedings of the 53rd US Rock Mechanics / Geomechanics Symposium
Subtitle of host publicationNew York, 23-26 June 2019
PublisherAmerican Rock Mechanics Association (ARMA)
Number of pages8
Publication statusPublished - 2019
Externally publishedYes
Event53rd U.S. Rock Mechanics/Geomechanics Symposium - New York Marriott, Brooklyn, United States
Duration: 23 Jun 201926 Jun 2019


Conference53rd U.S. Rock Mechanics/Geomechanics Symposium
Abbreviated titleARMA 2019
Country/TerritoryUnited States
Internet address


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