The mechanics of uncemented carbonate sands

Abstract

The mechanical behaviour of a typical biogenic carbonate sand was investigated using triaxial testing at standard and also at high pressures up to 8 MPa. The test results show that despite the particle breakage which is characteristic of these soils, their behaviour is still qualitatively similar to that observed for more commonly encountered soils, and is consistent with the principle features of critical state soil mechanics. The higher stresses used in these tests were an order of magnitude greater than are generally used in soils testing, and the values of some individual soil parameters were found to be outside the range of normal experience. Micrographic and gradings analyses were used to examine the influence of isotropic and shear stresses on particle breakage. Triaxial test results illustrate the influence of this breakage on the mechanical behaviour of the soil. Le comportement mécanique d'un sable carbonaté biogénique typique a été étudié par des essais triaxiaux à pression normale et aussi à des pressions élevées jusqu'a 8 MPa. Cet article présente les résultats des essais indiquant que malgré la rupture des particules qui est caractéristique pour ces sols, leur comportement reste du point de vue de qualité semblable à celui observé dans le cas de sols plus fréquemment rencontrés et s'accorde avec les caractéristiques principales de la mécanique des sols dans l'etat critique. Les contraintes les plus élevées employées au cours de ces essais étaient supérieures d'un ordre de grandeur à celles génera-lenient utilisées dans les essais effectués sur les sols et on a trouvé que les valeurs de quelques paramètres individuels du sol se trouvaient hors des valeurs normalement enregistrées. Des analyses micrographiques et granulométriques pour étudier l'influence exercée par les contraintes isotropes et de cisaillement sur la rupture des particules. Les résultats des essais triaxiaux illustrent l'influence de cette rupture sur le comportement mécanique su sol.

On the Particle Size Distribution of a Basaltic Till

“…5, show clear yielding for the oarse-grained'' specimens marked by the high curvature of their compression curves, and convergence after yielding. This is in agreement with results from for example high pressure tests on carbonate Dog's Bay sand (Coop, 1990;Coop and Lee, 1993), where yielding and post-yield deformations were found to be associated with particle breakage. Therefore, in most sands, the unique Normal Compression Line represents the locus of particle breakage in the soil.…”

Discrete element modelling of one-dimensional compression of cemented sand

“…2, although the applied stress is not high enough to conclude if the normal compression lines (NCLs) are converging or independent of one another. Although some of the literature considers isotropic compression and some one-dimensional compression, it is widely accepted that soils have the same compression slope in both [9][10][11].…”

A spheropolygonal-based DEM study into breakage under repetitive compression

“…4. Decreasing particle irregularity has been shown by [9] to increase the soil stiffness; it has also been shown that a well-graded sand will have a lower LCC gradientor equivalently, compression index, Cc-than a uniform grading of the same material [10]. These changes produce a particle assembly which has a greater packing potential so particles are less free to move translationally or rotationally and the assembly therefore becomes stiffer.…”