Analysis of Instability Conditions for Normally Consolidated Soils

摘要

The traditional method of undrained stability analysis of geostructures is addressed first. It is shown that the reason why it is possible to predict the collapse condition by using only total stresses is linked to that this method is not a limit analysis (in the sense of plasticity theory) but an analysis of the instability condition under the constraint of no volume change. It is shown further that a normally consolidated or slightly overconsolidated soil specimen may become unstable, under more general loading , for very low values of the stress level. Under convenient loading conditions, unlimited pore water pressure generation, drained or undrained shear banding, loss of controllability of the loading programme may take place still in the hardening regime, well before the limiting stress condition is achieved.