Numerical simulations of seismic and post-seismic behavior of tailings

Abstract

Several tailings impoundments have failed as a result of earthquakes in the last few decades. A majority of these failures were due to direct seismic loading, tailings liquefaction during shaking, or the post-seismic behavior of the tailings as it relates to the dissipation of excess pore water pressures that were generated during shaking. Previous work has indicated that the UBCSAND model (Byrne et al. 1995) is capable of simulating the cyclic simple shear testing response of low plasticity tailings over a range of consolidation stresses and cyclic shear ratios. However, the ability of the model to simulate the dynamic and subsequent behavior of such tailings for other conditions, such those induced by shakings table tests, has not yet been evaluated. In this regard, previous work has shown that the main components of the UBCSAND model cannot realistically simulate some specific responses, including the post-seismic volumetric strains related to excess pore water pressure dissipation. This paper presents numerical modeling results of the dynamic behavior of tailings from hard rock mines. It introduces a method for simulating their postseismic behavior by including an updating scheme for the elastic moduli into the UBCSAND model. The results of cyclic simple shear testing, seismic table testing and complementary experimental relationships were used to calibrate and validate the model with its new component.The simulated response of tailings during cyclic simple shear testing and for a complete seismic table test shows that the proposed approach simulates the experimental observations well. Level ground, seismically-induced liquefaction and post-seismic behavior of a 15-m-thick tailings deposit are also simulated, leading to post-liquefaction settlements that are in agreement with empirical relationships. résidus d'une épaisseur de 15 m soumis à un séisme mène à des tassements post-liquéfaction qui montrent une bonne corrélation avec ceux obtenus de relations empiriques.

A numerical investigation on hydro-mechanical behaviour of a high centreline tailings dam

“…where σ' v is the vertical effective stress, P a is the atmospheric pressure, and K and n are the coefficient and power. Based on the results of Rowe cell consolidation tests, the average elastic modulus of slimes is calculated to be 7 000 kPa, which is within the range of assumptions or measurements reported by Liang and Elias (2010), Jaouhar et al (2011), L. Bolduc (2012) and Ferdosi et al (2015b). Based on the assumptions of L-Bolduc and Aubertin (2014) and Ferdosi et al (2015a), the elastic modulus of waste rock is assumed to be 50 000 kPa.…”

Constitutive modeling of principal stress rotation associated with sand under simple shear loading

“…For example, Beaty and Byrne, 15 and Chowdhury 50 suggested protocols of UBCSAND for modeling the postliquefaction residual shear strengths inferred from field case histories of earthquake-induced liquefaction. 42,[51][52][53][54][55] Additionally, Park et al, 17 and Ferdosi 56 performed the effective stress analysis using the UBCSAND model adopt the analytical function of Sento et al 57,58 for postliquefaction reconsolidation volumetric strains.…”

Numerical Analysis of an Upstream Tailings Dam Subjected to Pond Filling Rates

“…As can be observed, while the stress-strain curves followed the nonlinear behavior of the experimental data well in the UBCSAND model, they overestimated the shear strength of the tailings materials significantly in the M-C model, regardless of the applied normal stresses (50 kPa, 100 kPa, 150 kPa) or the tailings types (layered tailings, compacted tailings). The UBCSAND model has also been used for materials in the development of excess pore water pressure-induced static liquefaction [29] or seismic liquefaction [15,30]. The M-C input parameter values of moraine and rockfill materials were adopted from previous works [31,32], as summarized in Table 1, except for the Poisson's ratio and the dilatancy angle.…”