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doi_cfbr_colloque2019_b16

Etude expérimentale des paramètres d’influence de la cohésion apparente des discontinuités des barrage-poids


Adrien RULLIERE, Jérôme DURIEZ, Claudio CARVAJAL, Laurent PEYRAS (IRSTEA), Patrice RIVARD (Univ. SHERBROOKE), Pierre BREUL (Univ Clermont Auvergne)

Éditeur : Comité Français des Barrages et Réservoirs - CFBR - ISBN 979-10-96371-09-9

Colloque : Justification des barrages : état de l’art et perspectives - Chambéry, France
Année d’édition 2019

Téléchargement : Actes du colloque

Title : Experimental study of the apparent cohesion influence parameters in gravity dam foundations joints

Résumé
Experimental study of the apparent cohesion influence parameters in gravity dam foundations joints

Abstract
International guidelines for gravity dam foundation design are suggesting to consider the rock-concrete foundation interface as unbonded and to use the Mohr-Coulomb criterion to assess the structure sliding safety factor. Engineers are invited to use the apparent cohesion with care but no consensus on the determination or on its influence parameters exists. Thus, an experimental study was developed and new insights on the apparent cohesion influence parameters (roughness, damages, interlocking, material mechanical properties, contact type and normal load) were found. 116 direct shear tests were performed under CNL conditions (Constant Normal Load) at normal stresses similar to those found inside a large gravity dam foundation (from 100 to 1000 kPa). Results showed that the higher the roughness, the higher the apparent cohesion values. Also, the previous damage of a joint reduces the apparent cohesion. The degree of interlocking also plays a role on the apparent cohesion. Indeed, for the same roughness, a significant drop of the apparent cohesion was observed between the perfect and well interlocked joints. For the same roughness and interlocking conditions, it appeared that the apparent cohesion is also affected by the joint material mechanical properties. However, the influence of the material on the apparent cohesion is lower than that of the roughness or interlocking. An increase of the normal load also led to an increase of the apparent cohesion. These observations on the apparent cohesion influence parameters suggest that using the apparent cohesion in calculations or in numerical modeling for assessing the shear strength of rock joints may be realistic.

Citation
RULLIERE, DURIEZ & Al. Etude expérimentale des paramètres d’influence de la cohésion apparente des discontinuités des barrage-poids. In Colloque Justification des barrages : Etat de l’art et Perspectives. Chambéry : CFBR - 27,28 novembre 2019. ISBN 979-10-96371-09-9. doi : 10.24346/cfbr_colloque2019_b16


Voir aussi : Colloque Justification des barrages : état de l’art et perspectives

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