Effects of particle size–strength and size–shape correlations on parallel grading scaling. Issue 2 (17th June 2020)

• Record Type: Journal Article
• Authors: Ovalle, C.; Dano, C.
• Is Part Of: Géotechnique letters. Volume 10:Issue 2(2020)
• Page Start: 191
• Page End: 197
• Publication Date: 2020-06-17
• Subjects: shear strength -- particle-scale behaviour -- laboratory tests; Geotechnical engineering -- Periodicals; Engineering geology -- Periodicals; 624.151
• DOI: 10.1680/jgele.19.00095
• Languages: English
• ISSNs: 2045-2543

Abstract

Abstract : Waste mining rock and rockfill materials contain coarse clasts that could easily reach more than 1 m in size. Small scaling techniques for mechanical testing on such coarse materials require altering the particle-size distribution (PSD), by reducing maximum grain size to be able to fit a sample in a laboratory device. To capture the stress−strain behaviour, it is assumed that the reduced PSD has to be parallel to the prototype grading. However, individual grain properties could change with particle size, such as shape and crushing strength. Parallel scaling techniques have been widely applied in rockfill materials, however, the effects of particle-size correlations have been rarely considered, and its effects remain not well understood. This paper presents experimental data on particle-size correlations with both particle shape and particle strength, together with triaxial tests on parallel graded samples of a shale rockfill material. The results show that inverse particle-size−strength correlation results in decreasing particle crushing in finer samples, while particle size−shape correlation could contribute to increase particle crushing in finer samples comprising more elongated grains. Depending on characteristic particle size, one of these opposed trends will prevail and control the material behaviour.