Determination of the tensile strength of unsaturated tailings using bending tests

Bending tests were conducted on specimens of unsaturated tailings from three hard rock mines to evaluate their tensile strength. Saturated samples were prepared at an initial water content, w 0 , of 40% and then naturally dried under ambient conditions to pre-selected degrees of saturation, S r , which can be related to the corresponding suction using the water retention curve. The basic interpretation of the bending tests results is based on an elastic–brittle behavior. The results show how the tensile strength, σ t , of unsaturated tailings varies with water content, w (and S r ). The experimental data are also used to evaluate Young’s modulus in tension, E t , and to estimate the apparent cohesion, c app , as a function of S r . Predictive equations are also applied to estimate the values of σ t of unsaturated tailings using the water retention curve.