Effects of swelling during saturation in triaxial tests in clays

Effects of swelling during saturation in triaxial tests on compressible Chicago glacial clays are assessed from results of triaxial compression tests on block samples cut from excavations, thin-wall Shelby tube samples, and reconstituted specimens. The results are presented in terms of the stress-strain response during saturation, k₀ reconsolidation and shearing. Bender element tests were also performed to investigate the effects of swelling on the shear wave velocities during k₀ reconsolidation. Results showed that the swelling during saturation lowered the shear wave velocity, thereby inferring a change in the original structure of natural clay. Responses at strains less than 0.01% were most affected by the saturation-induced swelling. To minimize these changes, it is recommended that the measured residual stress is applied prior to saturating the soil. Based on these results, the saturation stage should be considered as much a part of a triaxial test as consolidation and shearing.