Centrifuge modelling of seepage through tailings embankments

Abstract

Tailings storage facilities (TSFs) are manmade geotechnical structures usually comprising a perimeter embankment, fill material (the tailings) and a water-level control system. The key issues often raised in TSF operation are uncertainties surrounding likely seepage to the environment and accurate prediction of seepage surfaces for input into stability assessment. Critically, TSFs are much more complex than the current numerical models conventionally assumed. This paper presents techniques for investigating steady-state and drawdown seepage behaviour of TSF embankments using a fixed-beam geotechnical centrifuge. The development of experimental equipment for centrifuge testing is described and novel methods to characterise model materials preliminarily, using a ‘desktop’ centrifuge, is presented. Good agreement is found between experimental results from the fixed-beam centrifuge and those predicted by the GeoStudio SEEP/W software package for steady-state and drawdown conditions at all tested hydraulic gradients.