Volume 22, Issue 3 (September 1999)
The Effects of Varying Centerline Tube Sampling Disturbance on the Behavior of Reconstituted Clay
In order to simulate varying degrees of disturbance of soil at the centerline of a tube sampler, triaxial stress and strain path tests have been carried out on normally consolidated and overconsolidated reconstituted London clay specimens. The tests were carried out using an automated system capable of controlling both stresses and deformations imposed on specimens. The specimens were instrumented with local axial and radial strain and mid-plane pore pressure measuring devices.
Test results indicate that the most pronounced effects due to imposed tube sampling strains in reconstituted normally consolidated London clay are significant reductions of mean effective stress and undrained small-strain stiffness, which are accompanied by reductions in the excess pore pressure generated during shearing. The higher the magnitudes of tube sampling strains, the greater the change in behavior. In over-consolidated reconstituted London clay, however, laboratory simulation of tube sampling strains together with deviatoric stress relief (i.e., “ideal” sampling) causes little change in effective stress, stiffness, and strength.