Local displacements and void ratio evolution to critical state were evaluated for dilative sand specimens using the technique of Digital Image Correlation (DIC), which operates by mapping pixel movements between digital images. High-resolution digital images were taken of in-plane displacements throughout plane strain compression. The evolution of displacement from uniform to bifurcation to failure was quantitatively analyzed, providing insight regarding the point of onset of bifurcation. Displacement points within a shear band were isolated for strain computation, enabling assessment of critical states. The dependency of Critical State Line (CSL) position in void ratio-effective stress space on deposition void ratio was investigated by consolidating groups of specimens from similar initial void ratios. Uniformity of volumetric strain along the length of a shear band was investigated. Shear band thickness and inclination were measured. Results suggest a dependency of CSL position on initial or deposition void ratio.
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