Static and Cyclic Triaxial Loading Tests of K₀-consolidated Clay

Abstract

A new automatic control triaxial apparatus and testing methods are explained for monotonic and repeated loading tests after isotropic, K₀ or constant stress ratio consolidation. The double cell type lateral strain measuring system with new ideas is adopted to achieve the condition of K₀-consolidation. The test results proved that this new system worked very well in comparison with the conventional tests. Shear behaviour after.K₀-consolidation was quite different from those of isotropically consolidated clays. The influence of K₀-consolidation can be observed, particularly in the compression side, in the existence of a phase change line and the increase of the critical state line slope. In repeated loading after K₀-consolidation, the amount of plastic strains differ, depending on whether the deviatoric stress is above or below the stress difference qK0 or the stress ratioηK0, after consolidation. In a region larger than qK0, soil behaviours indicating effects of K₀-consolidation were observable, such as the leaning of the effective stress path to the right and the fact that the axial strain during unloading scarecely changed. In the lower regions, however, there was no such difference between isotropically and K₀-consolidated clays.