Effect of particle size and strain conditions on the strength of crushed basalt

Abstract

This paper describes the results of an investigation carried out to study the influence of particle size, stress level, density, method of consolidation, and strain conditions on the strength and compressibility of crushed basalt. All specimens were prepared at medium or high density, consolidated isotropically or under KO consolidation, and sheared under effective confining pressure ranging from 443 to 2297 kPa. The material used in the test program had a straight line grain size distribution with maximum particle size ranges from 0.63 to 76.2 mm and minimum particle size equivalent to No. 30 U.S. standard sieve size:The tests indicated that an increase in the particle size (i.e., gradation) increases the strength and decreases the axial and the volumetric strain at failure. The study indicated further that the crushed basalt under triaxial compression has a lower shear strength than when sheared under plane strain conditions. Particles crushed were significantly influenced by the stress level and gradation and to a lesser degree by density of material.Cet article prCsente les rCsultats d'une Ctude de l'influence de la dimension des particules, du niveau de contrainte, de la densitC, de la mCthode de consolidation et des conditions de dkformation sur la rksistance et la compressibilitC du basalt concassi. Tous les Cchantillons ont Ct C prCparCsB une densite moyenne B forte, consolidts sous condition isotrope ou KO, et cisaillts sous des contraintes effectives comprises entre 443 et 2297 kPa. Le matkriau utilisC dans le programme d'essais avait une courbe granulomCtrique rectiligne entre une dimension maximum variant de 0,63 i 76,2 mm et une dimension minimum correspondant au tamis standard U.S. no 30.Les essais indiquent qu'une augmentation de la dimension des particules produit une augmentation de la rCsistance et une diminution des dCformations axiales et volumiques B la rupture. L'Ctude a montrC Cgalement que le basalt concassC prksente une risistance au cisaillement plus faible en compression triaxiale qu'en condition de dCformation plane. Le broyage des particules est fortement influencC par le niveau de contrainte et la granulomCtrie, et a un degrC moindre par la densite du matCriau.Mots-clh: sols pulvCrulents, densitt, essais de cisaillement, diagrammes contrainte-dCformation, essais de compression, barrages en enrochement.

Discussion of “Influence of Particle Size and Gradation on the Stress-Dilatancy Behavior of Granular Materials during Drained Triaxial Compression” by Samaneh Amirpour Harehdasht, Mourad Karray, Mahmoud N. Hussien, and Mohamed Chekired

“…4(a), the critical state friction angle f cs shows a clear reliance on the mean particle size, increasing with the increase of d 50 ; that is, f cs is a variable relating to the mean particle size instead of a constant, as stated by the authors in the original paper. This finding agrees well with the results of laboratory tests and numerical simulations done by other researchers (Al-Hussaini 1983;Sitharam and Nimbkar 2000;Cerato and Lutenegger 2006). Fig.…”

Evaluation of rock size on the mechanical behavior and deformation performance of soil-rock mixture: a meso-scale numerical and theoretical study

“…The second viewpoint presents a positive relationship between shear strength or elastic modulus and particle size. Mosaid (1983) carried out triaxial consolidation drainage shear tests on materials with the particle size of 0.6-6.4 mm, 0.6-12.7 mm, 0.6-25.4 mm, 0.6-50.8 mm, and 0.6-76.2 mm, respectively; the tests results indicated that an increase in particle size would increase the shear strength of sample. Raymond and Diyaljee (1979) also obtained the same test result.…”

Shear strength of angular granular materials with size and shape polydispersity

“…Although numerous research has been reported about the effect of these techniques on the shear strength of granular materials, the results widely vary up to the point of being contradictory. While some studies have indicated that shear strength decreases with grain size [Marachi et al, 1972, Ovalle et al, 2014, Varadarajan et al, 2003, Xiao et al, 2014, Zeller and Wullimann, 1957, others have shown the opposite behavior [Al-Hussaini, 1983, Cao et al, 2020, Deiminiat and Li, 2022, Linero et al, 2007. The sources of this apparent contradiction are presumably found in several sample and testing characteristics, and inherent material properties.…”