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Abstract

We characterize the structure of densely packed frictional granular spheres cyclically sheared between parallel walls under constant pressure boundary conditions with a fluorescent refractive index matched liquid imaging technique. This technique allows us to measure the three-dimensional positions of the particles and obtain the Voronoi tessellation corresponding to the particles in the bulk. The angular correlation of the particles was measured by the bond order metric, Q$_{6}$ and Q$_{4}$. Based on these values the evolution of different crystal-like environments as a function of the packing fraction will be discussed. We will also present how the Voronoi statistics like the mean number of faces, face area distribution, number of edges per face, and mean Voronoi polyhera volume vary as a function of shear cycle number.