Predictive Models for Earthquake Response of Clay and Sensitive Clay Slopes

Abstract

Earthquake-induced permanent displacement and shear strain are suitable indicators in assessing the seismic stability of slopes. In this paper, predictive models for the permanent displacement and shear strain as functions of the characteristics of the slope (e.g. factor of safety) and the ground motion (e.g. peak ground acceleration) are proposed. The predicted models are based on numerical simulations of seismic response of infinite slopes with realistic soil profiles and geometry parameters. Predictive models are developed for clay and sensitive clay slopes. A strain-softening soil model is used for sensitive clays. A comparison of the permanent displacement and strain predictions for clay and sensitive clays reveals that the displacement and shear strains are larger for sensitive clays for the same slope geometry and similar earthquake loading conditions. A comparison of the displacement predictive model with other predictive models published recently reveals that the displacement predictions of the proposed model fall into the low estimate bound for soft slopes and into the high estimate bound for stronger slopes. Permanent displacements from a limited number of 2D FE analyses and from predictive models compare well; however, the predictive model for shear strain tends to overly estimate the shear strains. This is a typical effect of 2D geometry, which represents a conservative situation. As the size of the slope increases, this effect is diminished, and the 2D results tend more to the 1D results as captured by the predictive models developed in this paper.