The self-weight consolidation of oil sands tailings and kaolinite slurry is modelled using a new geotechnical beam centrifuge located at the University of Alberta (Geomechanical Reservoir Engineering Facility (GeoREF) centrifuge). The centrifuge is used to create a prototype-effective stress regime in the model, and centrifuge tests are conducted at different initial compositions at acceleration levels of 40 to 100g. The objectives of the centrifuge tests are to study the long-term consolidation behaviour, derive consolidation parameters, verify modelling procedures and to evaluate time-domain reflectometry application for solids content profile monitoring during centrifuge testing. The interface settlement, pore pressure and solids content profiles of the consolidating materials are monitored in-flight. Large strain consolidation parameters are derived from centrifuge tests and compared with parameters determined from a large strain consolidometer. The paper describes the modelling aspect as well as the instrumentation and monitoring of centrifuge tests. The centrifuge results are presented, discussed and compared using results from large strain numerical models.
In this paper, segregation related to the application of high centrifugal acceleration and the effect of thixotropy in modelling the settling behaviour of slurry/soft soils using a centrifuge are examined. Settling column and centrifuge tests were conducted on slurry/soft soils at various sand fines ratios (SFR) to define a segregation boundary using the ternary diagram. A segregation boundary based on centrifuge and settling column tests are established and the results indicate that the application of high gravity in centrifuge tests prompts and enhances segregation. It is also found that the segregation boundary of high gravity tests is a function of applied acceleration level, grain size of sand, the percentage fines and clay contents. The application of formulas that estimate the maximum size of sand that remain in suspension are evaluated and found conservative at high gravity tests. The shear strength of slurry/soft soils at various SFR and age were evaluated to assess the effect of non-gravity, time-dependent behaviour on strength and settling behaviour of slurry/soft soils. The results of the shear strength tests at various ages and composition indicate that strength gain is mainly due to thixotropy. The gain in shear strength due to thixotropy may not be properly modelled in centrifuge testing and may create difficulty in extrapolating centrifuge test results to prototype.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.