.. _R7.01.18:

**r7.01.18** Behaviour law of HOEK_BROWN amended
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**Summary**

This document describes a law of behavior for rocks. The plasticization criterion is a Hoek-Brown parabolic criterion. It is written in main constraints. The evolution of plastic deformations is of the "non-associated" type, formulated on the basis of a Drucker-Prager criterion whose friction angle changes with plasticization.

This law can be used in pure mechanics as well as in coupled thermo-hydro-mechanical modeling.

In thermo-hydro-mechanical modeling, it can be used in effective stresses or in total stresses:


* In the first case, it is the actual constraints that are subject to meeting the Hoek and Brown criterion. Plastic deformations are calculated using the Drucker surface and the angle of friction in the space of the effective stresses


* In the second case, it is the total constraints that are subject to meeting the Hoek and Brown criterion. Plastic deformations are calculated using the Drucker surface and the angle of friction in the total stress space




.. toctree::
    :hidden:

    self

.. toctree::
    :maxdepth: 2
    :numbered:

    Introduction
    Notations
    Mod_le_continu
    Forme_incr_mentale
    Calcul_des_d_riv_es
    Calcul_de_l_op_rateur_tangent_coh_rent
    Calcul_de_l_op_rateur_tangent_en_vitesse
    Algorithme
    Bibliographie
    Fonctionnalit_s_et_v_rification
    Description_des_versions_du_document