Penetration rate effects during centrifuge tests with a focus on remoulded strengths in IOT

A series of full-flow penetrometer (T-bar and ball penetrometers) and piezocone tests were performed at varied penetration rates in a geotechnical centrifuge to investigate rate effects on penetration resistance, with a focus on the remoulded resistance of a clayey iron ore tailings. The effect of penetration rate on sleeve friction, pore-water pressure generation, and tip resistance is studied in terms of normalised penetration velocity from the cone penetration tests with pore pressure measurement. The effect of penetration rates on the remoulded resistance was studied by conducting cyclic tests across two different depth ranges with the full-flow penetrometers. The strong dependence of remoulded strength on the penetration rate was identified in terms of normalised penetration velocity. In addition, the shear strength inferred from in situ vane shear tests after remoulding was compared with the penetrometer results. The shear rate effect was consistent with the previous rate effects conducted on the same material using different testing techniques. The potential for partial drainage and viscous effects highlights the importance of considering rate effects for improved in situ characterisation of mine tailings.