Nested Newmark model to estimate permanent displacement of seismic slopes with tensile strength cut-off

Abstract

Nested Newmark model(NNM) is a conceptual framework to assessing post-earthquake movements including dispersed shear movements. The original NNM omits that the tensile stresses would be encountered in slopes induced by earthquakes. The purpose of this study is to introduce the tensile strength cut-off and the relevant failure mechanism into NNM and conduct the limit analysis to determine the seismic displacement. Parametric studies are carried out to further investigate the influence of the tensile strength and input ground motions on permanent displacement. Neglecting the tensile strength can underestimate the permanent displacements of slopes. As the peak acceleration increases, the underestimation becomes more significant. With the reduction of tensile strength, much larger deformation occurs next to the slope crest. Although the present results are limited to an example, the method is of value in practice to predict the post-earthquake profile of slope.

Keywords

slopes / limit analysis / earthquakes / permanent displacement / Newmark / tensile strength

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