11.5 Soil behaviour during undrained loading
Figure 11.10 shows the behaviour during undrained loading of sample W initially on
the wet side of the critical state and sample D initially on the dry side, both with the
same initial specific volume. The broken line in Fig. 11.10(a) is the yield curve which is
the intersection of the elastic wall with the state boundary surface so the samples yield
at YW and YD where the stress paths meet the yield curve. Thereafter the stress paths
follow the yield curve and reach the critical state line at the same point at Fu because
their specific volumes remain constant, as shown in Fig. 11.10(d). Figure 11.10(a)