The Effects of Centerline Tube Sampling Strains on the Undrained Behavior of Two Stiff Overconsolidated Clays
Some of the effects of tube sampling of stiff clays are examined. A strain path that simulates strains at the centerline of a tube sample as it is captured by a penetrating sampling tube was applied in the triaxial apparatus. Undrained triaxial strain path tests were performed on two stiff overconsolidated clays that had not previously been subjected to tube sampling. The response of the clays after simulated sampling and reconsolidation is compared with shear behavior established from tests on specimens taken from block or rotary-cored samples. The mean effective stress is reduced by about 10% as a result of the centerline tube sampling strain path. Stiffness is significantly reduced after simulated sampling and isotropic reconsolidation for both clays, whereas peak strength is only slightly affected.