ISSN: 1945-7545
CODEN: GTJODJ
Published Online: 28 February 2011
Page Count: 12

Effect of Sample Size on the Behavior of Granular Materials

Hu, Wei
Formerly Research FellowAssociate Professor, Research Institute in Civil and Mechanical Engineering, Ecole Centrale Nantes–Univ. of Nantes–CNRS UMR 6183State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu Univ. of Technology, NantesChengdu,

Dano, Christophe
Research Institute in Civil and Mechanical Engineering, Ecole Centrale Nantes–Univ. of Nantes–CNRS UMR 6183, Nantes,

Hicher, Pierre-Yves
Research Institute in Civil and Mechanical Engineering, Ecole Centrale Nantes–Univ. of Nantes–CNRS UMR 6183, Nantes,

Le Touzo, Jean-Yves
Research Institute in Civil and Mechanical Engineering, Ecole Centrale Nantes–Univ. of Nantes–CNRS UMR 6183, Nantes,

Derkx, François
Département Mesure Auscultation et Calcul Scientifique (MACS), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux, Paris,

Merliot, Erick
Département Mesure Auscultation et Calcul Scientifique (MACS), Institut Français des Sciences et Technologies des Transports, de l'Aménagement et des Réseaux, Paris,

(Received 18 March 2010; accepted 15 December 2010)

Abstract

Natural soils or coarse granular materials containing large particles such as rockfill or ballast are often an issue for geotechnical projects. However, since it is usually complicated or impossible to set up a big enough experimental apparatus to test these materials, their mechanical behavior remains poorly known. To circumvent this difficulty, we have developed a set of triaxial cells of various sizes to study the experimental behavior of granular soils containing particle sizes of up to 160 mm. This paper presents the first results of a two-part experimental study. The first part consists of triaxial tests on sand samples of different sizes in order to examine specimen scale effects. Pre-peak behavior is not affected by the specimen size, whereas post-peak behavior depends on the test conditions that control the development of strain localizations. In the second part, we present drained triaxial compression tests on large samples of calcareous rockfill materials that have parallel grain size distributions. The results show a nonstandard evolution of the friction angle in relationship to grain size if compared to similar studies on coarse granular materials. Although grain crushing occurs during compression, the strain-stress curves of the different materials with different grain sizes do remain close. We explain this phenomenon by the strength evolution of the individual grains with respect to their sizes.

Keywords:
triaxial cell, granular materials, rockfill behavior, coarse soil, size effect

Paper ID: GTJ103095
DOI: 10.1520/GTJ103095
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