Numerical simulation of ash-spills induced by dike failure on ash tailings impoundments - a case study

Abstract

A model developed for simulation of both discontinuous clear-water flows and hyper-concentrated discontinuous flows is validated on a real dike failure event, which happened on an ash-tailings impoundment on site. Numerical model is based on the MacCormack finite-difference scheme and involves constitutive equation in a form of the general yield-power law (Herschel-Bulkley's rheological model). The influence of the solid phase volumetric concentration on the propagation characteristics of the dike-break wave is analysed. Rheological properties of ash-water mixtures are determined in the laboratory using a tube viscometer. Definition of the corresponding constitutive equations is based on the test results. In that respect, the rheological properties of ash may be described by the Bingham model.