Hydro-Mechanical Behaviour and Critical State Conditions of Unsaturated Silty Tailings

The in-depth knowledge of the hydro-mechanical response of tailings finds its practical application as a fundamental tool to reliably assess the stability of the tailing storage facilities, which the high rate of recent collapses poses unacceptable fatalities with environmental and economic damages. This research investigates the hydro-mechanical behaviour of unsaturated fluorite ore tailings collected after the collapse of the Stava dams (Italy). The coupled hydro-mechanical response was studied by carrying out suction-controlled triaxial tests, the Critical State in unsaturated conditions was investigated by imposing different stress-paths, and the experimental results are compared with those obtained on the same material in saturated conditions. Outcomes are interpreted based on the Water Retention Curve (WRC), obtained by performing water retention tests on the same material.