Undrained shearing behaviour of oil sands tailings

Abstract

The instability of coarse oil sands tailings (CST) is investigated in this study by conducting a series of monotonic direct simple shear tests. Laboratory specimens were prepared using moist-tamping, dry deposition, and slurry deposition techniques to investigate the effect of sample reconstitution method and tailings fabric on CST's instability behaviour. CST specimens were then subjected to constant volume (CV), and constant vertical stress (drained) shearing at three different consolidated relative densities corresponding to loose, medium-dense, and dense conditions. The effects of consolidation vertical stress and void ratio on the instability and post-liquefaction strength of the CST specimens were examined. Shear wave velocity (VS) of the specimens were also measured using a pair of bender elements attached to the top and bottom caps of the simple shearing apparatus. The VS measurements were subsequently used to establish practical relationships with undrained strength ratios and yield friction angle of CST.