Undrained Strength of Anisotropically Consolidated Sand

Abstract

The strength of triaxial test specimens of saturated sand was investigated over a wide range of density, confining pressure, and anisotropic consolidation stress conditions. It was found that for any one initial density, the volume changes which occurred during consolidation were a unique function of the major principal stress, and were independent of the minor principal stress on the sample. The stress-strain curves and strengths determined from the drained tests on initially identical samples consolidated to the same minor principal stress were almost independent of the principal consolidation stress ratio \IK\dc\N. However, the undrained strength increased with increasing \IK\dc\N ratio. At low confining pressures the undrained strength followed the same pattern as previously established for isotropically consolidated undrained tests. For high pressures and high \IK\dc\N conditions, the peak undrained strength was relatively high. However, this condition was unstable and required only a minor increase in load to reduce the strength to a lower residual value which was similar to the strength predicted by previously established methods.