Identification of possible new failure mechanisms for the collapse of tailings dams

Abstract

Static liquefaction has been considered as one of the most common failure mechanisms for tailings dams. However, for tailings with relatively high permeability, the assumption of an undrained condition becomes questionable under static loading conditions. In fact, many granular soil or tailings at its in-situ density may not liquefy under static, undrained conditions. In this paper, the problems with the current design approaches for tailings dams are identified. Laboratory test results are presented to demonstrate that granular soil can become unstable under drained or nonundrained conditions. Based on the testing data, two possible new failure mechanisms for tailings dams are proposed.