Some aspects of the compressibility behaviour of a clayey sand

Abstract

The intrinsic behaviour of a residual clayey sand derived from sandstone was investigated in one-dimensional compression. The data show some interesting differences when compared with other published data, in that no unique normal compression line can be identified. Although the compressibility on first loading is similar to that for many sandy materials at states on their normal compression lines, the locations of the compression curves were found to be a function of the initial voids ratio, and there was no convergence at higher stresses. Tests on a model clay-sand mixture indicated that this behaviour is common to gap-graded clayey sands. Martins et al.Résumé : Le comportement intrinsèque d'un sable argileux résiduel dérivé d'un grès a été étudié en compression unidimensionnelle. Les données montrent des différences intéressantes lorsque comparées avec d'autres données publiées, en ce qu'une ligne de compression normale unique ne peut être identifiée. Quoique la compressibilité durant le premier chargement est similaire à celle de plusieurs matériaux sableux dans des points localisés sur les lignes de compression normale, on a trouvé que les positions des courbes de compression étaient fonction de l'indice de vide initial, et qu'il n'y avait pas de convergence aux contraintes plus élevées. Des essais sur un mélange modèle argile-sable ont indiqué que ce comportement est typique des sables argileux à granulométrie discontinue.

The role of particle breakage in the mechanics of a non-plastic silty sand

“…Recent research on soils with intermediate grading, such as silty sands, has tended to emphasise their ''transitional'' mode of behaviour, with compression paths that do not converge in the e:ln p 0 plane, even at very large stress levels and also Critical State Lines that are dependent on the initial void ratio (Yamamuro and Lade, 1998;Martins et al, 2002;Ferreira and Bica, 2006;Nocilla et al, 2006). For these soils, the ability of the soil to sustain different void ratios at the same stress level must represent the effects of a robust form of fabric.…”

Engineering characterisation of Norwegian glaciomarine silt

“…Other researchers have shown that a flattening of the log σ v ' versus e is characteristic of transitional soils (e.g. Martins et al, 2001). For the lower clayey silt the curves are somewhat more rounded and some rough estimate of the yield stress is possible.…”

“…These soils consistently have an intermediate grading between sand and clay. Examples include a gap-graded residual sandstone from Brazil (Martins et al, 2001;Ferreira & Bica, 2006).…”

A dual-surface damage model and evaluation for natural soils within the thermomechanical framework

“…Some previous test results of the natural and artificial samples show these notable effects of structures on mechanical characteristics [1][2][3] . Meanwhile, the definition of the effects of structures in samples and the handling of the natural soil become very difficult, because the intrinsic properties of soils cannot be established independently.…”

“…Many factors, such as state, stress history and structure etc. are often used to investigate the most important aspects of the structured effects for natural clays [2,3] . An effective methodology to incorporate these complex factors into a whole concise and rational way would undoubtedly be attractive.…”