Experimental Study on Shear Localisation in Granular Materials Within Combined Strain and Stress Field

The characteristic features of the shear zones formation in deforming granular materials were investigated using particle image velocimetry (PIV), which was combined with a photo-elastic study of the stress field. Laboratory tests were performed for an active translation of rigid retaining wall. PIV is an optical technique for measuring displacement fields from successive digital images and was employed to analyse experiments on two different granular materials, composed of (1) sand grains and (2) glass granules. The tests on glass granules were supplemented by taking photo-elastic images in circularly polarised light to gather information on changes in the average stress field, accompanying the specimen deformation. Attention was focused on the effect of the initial density, grain coarseness and magnitude of wall displacement on shear localisation within a strain field and its geometrical relation to some structures found in the stress field.