A particle-tracking method for experimental investigation of kinematics of sand particles under triaxial compression

Particle kinematics including particle translation and particle rotation, plays a very important role in the shearing behavior of granular soils. In this study, a particle-tracking method based on particle volume (or particle surface area) is presented in detail and applied to the acquisition of particle kinematics of a uniformly graded sands undergoing shearing in a mini-triaxial apparatus using the X-ray synchrotron radiation technique. The effectiveness of this method, and the effects of different tracking criteria (i.e., particle volume and particle surface area) and tracking parameters on its tracking performance are examined. It is found that the particle tracking based on the two tracking criteria provides consistent results of particle kinematics with high accuracy, given that appropriate tracking parameters are used. The presented particle-tracking approach and the research findings will be useful for the measurement and quantification of particle-scale kinematics of granular materials.