City Research Online

Abstract

Understanding the stress transmission mechanisms and breakage of soils composed of a fine and coarse fractions is critical for the design of many geotechnical structures such as pile driving and large embankment dams. A series of strain controlled one-dimensional compression laboratory experiments were carried out using glass beads to investigate the effect of the fine faction on the macroscopic response of the material. A wide range of stress varying from 10 to 250MPa was considered. Glass beads with diameters between 0.5 and 4mm were used to form granular mixtures with fines content ranging from 0 to 100%. This study shows the potential of strain controlled testing to provide further insights into the fabric evolution of granular materials undergoing grain breakage. When compared to conventional load controlled testing, the force:displacement curve obtained during strain controlled testes provides a better correlation between the macroscopic response and the grain-scale phenomena. The response of mono-sized samples is used as a reference to better understand the contribution of both the coarse and the fine factions to the behaviour of the mixture. Preliminary results have suggested that as breakage progresses, the grain size distribution evolves towards a fine fraction threshold value, beyond which the behaviour is governed by the fine component. Previously proposed relative breakage parameters are also used to demonstrate the influence of the fine faction in the final grading of the material. These finding, also supported by recent numerical studies, can provide valuable guidance for geotechnical practice.

Publication Type:	Conference or Workshop Item (Paper)
Departments:	School of Science & Technology > Engineering

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