Methodology for estimating seismic coefficients for performance-based design of earthdams and tall embankments

Abstract

Following an overview of pertinent literature, this paper presents a new methodology for estimating seismic coefficients for the performance-based design of earth dams and tall embankments. The methodology is based on statistical regression of (decoupled) numerical data for 1084 potential sliding masses, originating from 110 non-linear seismic response analyses of 20 cross sections with height ranging from 20 to 120 m. At first, the methodology estimates the peak value of the seismic coefficient k(hmax) as a function of: the peak ground acceleration at the free field, the predominant period of the seismic excitation, the non-linear fundamental period of dam vibration, the stiffness of the firm foundation soil or rock layer, as well as the geometrical characteristics and the location (upstream or downstream) of the potentially sliding mass. Then, it proceeds to the estimation of an effective value of the seismic coefficient k(hE), as a percentile of k(hmax), to be used with a requirement for pseudo-static factor of safety greater or equal to 1.0. The estimation of khE is based on allowable permanent down-slope deviatoric displacement and a conservative consideration of sliding block analysis. (C) 2013 Elsevier Ltd. All rights reserved.