Strain localization measurements in undrained plane-strain biaxial tests on Hostun RF sand

Results from a series of biaxial undrained tests on a fine, angular, quartz sand (Hostun FR) are presented. Both dilative and contractive specimens were tested. Strain localization in the specimen was recorded using a false relief stereophotogrammetric method, which allows a full-field measurement of the incremental strain within a specimen throughout the test. Incremental strain maps are obtained at different states on the stress–strain response. It is shown that shear banding can take place in both contractive and dilative specimens, but for the latter the onset of localization is delayed until cavitation takes place in the pore-fluid. It is concluded that in dilative granular media, non-drainage can preclude localization as long as cavitation in the pore-fluid does not relax the isochoric constraint. Copyright © 1999 John Wiley & Sons, Ltd.