On the Particle Size Distribution of a Basaltic Till

Abstract

Stress and strain history play a major role in deˆning theˆnal grading of a soil, and by studying how the particle size distribution of a soil evolves with stress and strain it may be possible to highlight some important aspects of the sediment past history. In this paper, the characteristics and evolution of the grading of a till from Iceland, so-called Langj äokull sediment, are examined. Specimens of the till were tested in compression (triaxial, oedometer tests) to very high pressures, and in shearing (triaxial, ring shear tests) to very high strains. The change in grading corresponding to particle breakage during compression and shearing was monitored using sieve analysis and scanning electron microscopy. The results show that the particle size distribution of the till, which is well graded, does not evolve when the till is subjected to high stresses or strains. Additional tests on specimens made of the larger-sized till particles did however show signs of breakage during testing. This suggests that the current natural grading of the till was achieved by incessant shearing during its past history, and corresponds to an ultimate,``critical'' grading. This is conˆrmed by the mineralogical analysis of the sediment, which highlights a single parent rock and weathering of the particles by mechanical processes only.

A boundary-spheropolygon element method for modelling sub-particle stress and particle breakage

“…Breakage is caused by many reasons, such as strong compressive loading, large shear displacement, extreme temperature, dehydration or chemical effects. Based on laboratory studies, it is concluded that breakage causes changes in particle size distribution [1][2][3][4] and particle shape [5,6], which in turn change the state variables, such as density and compressibility, that govern the mechanical behaviour of the bulk granular material. These studies have provided a framework for studying particle breakage.…”

Fractal Pattern of Particle Crushing of Granular Geomaterials during One-Dimensional Compression

“…Advances in Civil Engineering Advances in Civil Engineering [41], the ratios between the 3D of the created particles by crushing are not much di erent. Hence, it is reasonable to guarantee the validity of using the laser particle analyzer to describe that part of PSD.…”