On the mechanics of filtered compacted consolidated and overconsolidated iron ore tailings at high pressures

Abstract

The mechanics of filtered compacted normally consolidated (NC) and overconsolidated (OC) iron ore tailings (IOTs) was studied by performing triaxial testing at high pressures of up to 120 MPa. The OC specimens were obtained by isotropically compressing compacted IOT to 120 MPa, unloading it to distinct confining pressures, and shearing at constant radial stress. Particle size distribution analyses were used to examine the effect of compression and shear stresses on particle breakage. Additionally, the triaxial test results illustrate the stress history influence on the deviatoric stress–axial strain–volumetric strain curves, as well as on the IOT peak strength. Furthermore, these results also show that the amount of breakage during the shearing stage plays an essential role in the geomaterial’s response, marking the existence of curved critical state locus in both v–ln p′ and q– p′ planes, which is unique in the studied confined stress range (4–120 MPa) for the compacted NC and OC (considering OC ratio up to 30) IOTs.