Strain localization in sand: Plane strain versus triaxial compression

A comprehensive experimental investigation was conducted to investigate the effects of loading condition and confining pressure on strength properties and localization phenomena in sands. A uniform subrounded to rounded natural silica sand known as F-75 Ottawa sand was used in the investigation. The results of a series on conventional triaxial compression (CTC) experiments tested under very low-confining pressures (0.05-1.30) kPa tested in a microgravity environment abroad the NASA Space Shuttle are presented in addition to the results of similar specimens tested in terrestrial laboratory to investigate the effect of confining pressure on the constitutive behavior of sands. The behavior of the CTC experiments is compared with the results of plane strain experiments. Computed tomography and other digital imaging techniques were used to study the development and evolution of shear bands.