Effects of Polymer Treatment on Undrained Strengths and Cyclic Behavior of a Low-Plasticity Slurry

A laboratory study was undertaken to assess the effects of polymer treatment (PT) on the monotonic, cyclic, and postcyclic behavior of a low plasticity slurry using a direct simple shear (DSS) apparatus. This study was conducted to extend the results of previous testing that assessed the effects of PT on the same material's consolidation behavior and critical state line. Consistent with previous tests on this material, DSS testing indicated that PT resulted in lower consolidated densities at a given magnitude of effective stress, and higher undrained shear strengths at a given density. PT appeared to increase the effects of strain rate on strength, whereas both PT and untreated materials responded similarly to the effects of overconsolidation. Cyclic and postcyclic testing indicated essentially indistinguishable results for the two materials. The effects of PT were seen to persist at vertical effective stresses up to 800 kPa. The potential implications of these findings for tailings design are discussed. (C) 2017 American Society of Civil Engineers.