Undrained Shear Tests on Clays

The proposed model describes the anisotropic properties of rate-independent saturated clays under undrained loading conditions. The model is applied to relate the various undrained shear strengths measured in common soil tests, including laboratory triaxial, plane strain, simple shear, and in-situ pressuremeter tests. The model predictions are shown to agree very well with available experimental test results. It is shown that the disturbances caused by the installation of the pressuremeter probe affect the derived shear stress-strain curves significantly, and are responsible for both their strain-softening features and high shear strengths. It is shown that a simple correction allows the true material shear stress-strain curve to be obtained from pressuremeter test results.