Simulation of tailings release in dam break scenarios using physical models

Abstract This article presents an experimental study performed to evaluate the volume of material released from the reservoir during a tailings dam failure event using models. To verify the influence of the parameters related to the breach geometry and the undrained shear strength (Su) in a failure event, 20 scenarios were simulated considering the absence of water in the reservoir. The material used to simulate tailings was bentonite, due to the similarity between the properties of the mud and mineral tailings sludge. Geometry and undrained shear strength were adjusted considering a scale factor of 1: 500. Regarding the studied parameters, the geometry of the breach was based on data from literature, whose lateral slopes were 0.50 H: 1V, 0.51 H: 1V and 0.5467 H: 1V in the trapezoidal breaches and 1: 1 (L / H = 0.97) and 1: 1 (L / H = 1.1) in the rectangular ones. The undrained shear strength ranged from 0.030 to 0.20 kPa. The results allowed to conclude that the mobilization of material increases with the average aperture width of the trapezoidal breach, being this the distinct behavior in rectangular breaches. Although the rectangular breaches had smaller average widths compared to the trapezoidal breaches, their base widths were larger and it is possible to infer that the mobilized volume depends on the geometry and the average width of the breach.