Étude expérimentale de la résistance en traction de résidus miniers non saturés à l'aide d'essais de flexion

The responsible disposal of mining wastes is a challenge that needs to be addressed. Mining operations produce a variety of waste materials such as waste rocks and tailings. Tailings, which contain a high percentage of fine particles, are generally stored in an initially saturated state, in tailing impoundments surrounded by dikes. Over time, such tailings tend to consolidate, and may become unsaturated due to drainage and evaporation, which makes their behavior more complex. It is important to understand the behavior of unsaturated tailings in order to predict their response in the field. Unsaturated tailings (as well as soils) as submitted to a negative water pressure (suction). This negative pressure creates capillary forces that contribute to the cohesion between particles. This apparent cohesion is not an inherent (intrinsic) property of the material as it varies with the amount of pore water and the related degree of saturation. The apparent cohesion is correlated to the tensile strength and it has a significant impact on the mechanical behavior of unsaturated materials such as mine tailings. This project focused on the evaluation of the tensile strength of unsaturated mine tailings. Several studies on this subject have been carried out on clayey soils and cemented materials, but granular (cohesionless) materials such as tailings from hard rock mines have not received much attention. Thus, this research aimed at developing a better understanding of the tensile behavior and associated properties (i.e. apparent cohesion and modulus of elasticity) of unsaturated tailings.