Numerical Analysis on the Stability of Upstream Mine Tailings Dam Under Seismic Loading

Upstream tailings dam expedites the construction process while lowering disposal and operational expenses. However, these dams are susceptible to liquefaction-induced failure under seismic conditions. This study explores the possibility of reducing differential settlement of the upstream tailings dam under liquefaction by densifying strategic portions of the beach area. Finite Element analysis is conducted using UBC3D-PLM constitutive law to model the liquefiable soil. The model is validated with a published centrifuge model of clayey embankment resting on liquefiable sand. The vertical deformation and post-liquefaction factor for unimproved and improved upstream tailings dam are numerically analysed. For an unimproved upstream tailings dam, vertical deformation to the tune of 300 mm was observed after 100 s of the seismic load, while the post-liquefaction stability factor was 1.33. In order to enhance the stability of the upstream tailings dam, the portion of the beach under the raised embankment was densified at a relative density of 70%. The width and depth of densified portions were varied as a function of beach length. This study suggests a method of improving the stability of the upstream tailings dam under seismic conditions while making the construction procedure of these dams easy and cost-effective.