Drained static bias effects on very loose silt tailings

Characterising the dynamic behaviour of soils under significant initial static bias is important for the safety of slopes, embankments, and tailings storage facilities (TSFs). However, this is a complicated task as: (i) the case history database is dominated by level ground sites, (ii) published laboratory element testing programs are often primarily carried out without an applied initial bias, (iii) there is uncertainty as to how liquefaction resistance varies with bias and/or density, and (iv) the criterion for selecting liquefaction triggering in such conditions has not achieved consensus. These issues are a particular challenge for filter-stack TSFs where the tailings can be in a very loose state owing to their moist placement, are under significant bias near the lower portion of the slope, and being often predominately siltsized do not fall well into common categorisations of “clay-like” and “sand-like” soils.