The impact of construction method on the seismic response of tailings sand dams

This paper examines the impact of construction method on the seismic performance of tailings sand dams. A well-established case study, related to the seismic response of the downstream constructed El Torito tailings dam, Chile, serves as a basis for comparison, to examine the impact of the centreline construction method on the seismic response. Advanced time domain finite element (FE) analyses, employing a hydro-mechanical (HM) coupled formulation, were carried out to simulate relevant aspects of the construction, operation and seismic responses of both simulated tailings storage facilities (TSFs). The tailings materials are modelled with a state parameter-based bounding surface plasticity model (BSPM) calibrated against laboratory and field data. A detailed construction and operation sequence is simulated with the aim of capturing the stress-state conditions in the TSF prior to the application of the 2015 Illapel and the 1985 Chile earthquakes. Depending on the characteristic of the examined motion, different deformation mechanisms are revealed for the two construction methods, affecting initially the dam-slimes interface and subsequently impacting the overall seismic stability.