Digital Image Correlation to Evaluate Shear Banding in Dilative Sands

Experimental results are presented of plane strain compression experiments on dense sands, in which the technique of Digital Image Correlation (DIC) was used to quantify localized displacements. The technique is described in detail. Results of accuracy tests of the DIC technique indicated that localized displacements were measured to an accuracy of ±0.008 mm. Typical DIC analyses produced approximately 250 displacement points within a shear band, which served as input for regression based strain computation, yielding highly accurate volumetric strain data for determining evolutions to critical state. Displacement data also were used to investigate volume changes outside the shear band. The DIC technique also enabled measurement of shear band inclination and thickness throughout the deformation process.