Stiffness and strength governing the static liquefaction of tailings

Abstract

In this study, the behavior of gold tailings is evaluated by a series of drained and undrained triaxial tests carried out in compression and extension and sheared under monotonic loading, allowing the critical state line (CSL) to be established. The observed highly nonlinear shape of the CSL under undrained loading was used to investigate the mechanics of tailings that were dictated by state transitions captured by both the state parameter and the measured values of shear-wave velocities. The definition of a zone is where state conditions may develop strain hardening (stable zone) or strain softening with high compressibility while maintaining the effective stress condition or, at the limit, a strong compressibility condition that may lead to collapse with loss of effective confinement and liquefaction. A set of original test data provides new evidence on how the small-strain shear modulus and shear strength can be coupled in the critical state framework to estimate the state parameter. This coupling is regarded as a key ingredient in characterizing the state of tailings because both the state parameter and the shear stiffness are proxies for flow liquefaction. (c) 2013 American Society of Civil Engineers.