The failure of the Stava Valley tailings dams (Northern Italy): numerical analysis of the flow dynamics and rheological properties

This paper presents an updated version of the one-phase continuum-mechanics-based RASH3D code, which integrates the existing rheological kernel (Frictional, Voellmy) with two new rheological laws (Bingham and Turbulent), and adds the possibility of changing the rheological properties of the flowing mass during the propagation process, using an integrated GIS function. The upgrade of the code originated from the intent to investigate the complex rheological behaviour of tailings flows released following a dam failure, which till now has been the subject of relatively few studies, despite the serious consequences that the collapse of a tailings dam can induce. The collapse of the Stava tailings dams was chosen as a case study, due to the amount of information that was available, and to the existence of different interpretations of the flow dynamics of this event in literature (e.g. Takahashi 1991 and Berti et al. 1997).