Effect of αs in Virgin Shear
Figure 8(a) shows the stress-strain relationships in virgin shear. These tests were carried out under p' = 100kPa, bs = 0.5 and various αs . The stress-strain curves are almost the same and independent of αs . Figure 8(b) shows εv - εs relationships in virgin shear for the same case as in Fig. 8(a). Although there is a small difference when εs is larger than 2%, the effect of αs is not apparent from this figure. These results indicate that the stress and strain non-uniformity is almost negligible especially in small strain and that the isotropically consolidated specimen is isotropic with respect to deformation and does not have inherent anisotropy before shearing.
Effect of bs in Virgin Shear
Figure 9(a) shows the stress-strain relationships in virgin shear where αs = 45o, various bs and p' = 100kPa. The inclination of the stress-strain curve in the initial state of shear is almost the same and independent of bs . However, the deviator stress q is smaller at the same shear strain εs when bs is larger. Figure 9(b) shows εv - εs relationships of virgin shear in the case of various bs and p' = 100kPa. Although the behaviour of volumetric strain εv is almost the same in spite of different bs values, there seems a tendency for the volumetric strain εv to be a little larger with a larger bs value.
