Performance-based assessment of the seismic pseudo-static coefficient used in slope stability analysis

Abstract

Pseudo-static slope stability procedures are often employed to evaluate the seismic performance of geotechnical slope systems, at least in the initial evaluation stages. To yield meaningful results, these methods should rely on parameters that are representative of the existing seismic demand and the properties of the geotechnical slope system being evaluated. This study proposes a performance-based probabilistic procedure to estimate the seismic pseudo-static coefficient (SPC) in a rational and transparent manner. The proposed procedure has its cornerstone on the evaluation of seismically-induced displacement (D) hazard curves, and it provides SPC estimations that are consistent with the allowable D level that a geotechnical structure can sustain, the properties of the sliding mass, and the seismic demand at the slope site. In addition, the calculated SPC can be directly associated with a return period or hazard design level for D. The proposed procedure can be applied to evaluate the seismic performance of a wide range of geotechnical slope systems potentially affected by earthquakes from different tectonic settings, such as subduction and shallow crustal earthquake zones (or a combination of both). The proposed procedure is implemented in a computational platform that facilitates its straightforward use in engineering practice. The implementations are fully automated for South America (i.e., Peru, Chile, Ecuador), Mexico, and the United States, but the proposed framework can be applied worldwide. Finally, an illustrative example for the application of the procedure in the seismic stability assessment of a slope system is provided.