One-dimensional (1-D) and two-dimensional (2-D) analyses of the seismic response of a geosyntheticlined heap leach pad were conducted using models that account for relative displacement (slip) between the liner system and the ore mass.
The 1-D analyses included equivalent linear and non-linear analyses. The equivalent linear analyses used the recommendations of Yegian et al. (1998) to model the impact of slip at the liner interface. The nonlinear analyses employed a weak layer to model slip at the liner interfaces. The 2-D analyses were non-linear time-domain analyses that employed a large-strain finite difference formulation and a linear elastic-perfectly plastic stress-strain model with the Mohr-Coulomb failure criterion to model the behavior of the liner interfaces. In all cases, analyses were also conducted without considering slip. Analyses were conducted using 3 pairs of time histories, each pair scaled to a different (and progressively increasing) peak ground acceleration. Comparison of the 2-D and 1-D analyses shows that: 1) use of slip elements in a 1-D model is an improvement with respect to conventional analysis without slip elements; 2) based upon comparison with the 2-D analyses with slip elements (believed to be more accurate, but more complicated to perform than 1-D analyses), additional calibration of 1-D models is required to improve their accuracy; and 3) as the seismically-induced loads and displacements vary along the liner, a 2-D model with interface slip elements is required to fully account for the impact of seismic loading on the performance of a geosynthetic liner system.