OBSERVATION OF GRAIN MOTION IN THE INTERIOR OF A PSC TEST SPECIMEN BY LASER-AIDED TOMOGRAPHY

Abstract

This paper presents a Laser-Aided Tomography/plane strain compression (LAT/PSC) testing method, a new PSC test allowing for a discussion of granular micromechanics with visualized granular fabrics. LAT technique is utilized to visualize in real time any arbitrary cross-section of a granular specimen. An image processing algorithm, suited for LAT imageries, was successfully developed to extract irregular perimeters of 3D grains, their fabric, and their motions (displacements and rotations) caused by loading. This micromechanical information together with the overall behavior of the granular assemblage, such as stress-strain curves and dilatancy characteristics, are quite useful for validating various empirical rules and/or numerical simulations, and also for providing new physical insights in this field.