Performance-based seismic assessment of slope systems

Abstract

The calculated seismic slope displacement provides a valuable index of the seismic performance of earth embankments and natural slopes. Sliding block models are often employed. The specific features of each sliding block method determine its reliability. Rigid sliding block models should not be used except for the limited case when the sliding mass is rigid. A coupled nonlinear deformable stick-slip sliding block model calculates reasonable seismic slope displacements. The primary source of uncertainty in assessing the seismic performance of an earth slope is the input ground motion. Hence, many ground motion records for each tectonic setting should be employed. Seismic slope displacement depends primarily on the earth structure's yield coefficient and the earthquake ground motion's spectral acceleration at the effective fundamental period of the sliding mass. Coupled nonlinear sliding block models enable the sensitivity of the seismic slope displacement and its uncertainty to key input parameters to be assessed. These procedures can be implemented within a performance-based design framework to estimate the seismic slope displacement hazard, which is a more rational approach.