Considerations in the earthquake-resistant design of earth and rockfill dams

Abstract

The factors to be considered in the earthquake-resistant design of dams are discussed and defensive measures which may be taken to mitigate the effects of these factors are summarized. Available information concerning the field performance of dams during earthquakes is reviewed and conclusions are drawn concerning the potential for earthquake-induced sliding for different types of construction materials and earthquake shaking intensities. Finally, available methods for evaluating the stability and deformations of the slopes of a dam due to earthquake shaking are reviewed and their applicability illustrated. Conclusions are drawn concerning the significance of the type of soil used for construction and the possibility of delayed failure, after the earthquake ground motions have stopped, due to pore water pressure re-distribution within an embankment. Suggestions are made concerning the appropriate role of analytical procedures in the overall assessment of the seismic stability of dams in relation to the uncertainties involved in the analysis procedures. L'article traite des facteurs à prendre en considération lors de la conception parasismique de barrages et résume les mesures de protection qui peuvent étre prises en vue d'atténuer les effets de ces facteurs. On y trouvera un examen des données disponibles relatives au comportement in situ de barrages au tours de séismes ainsi que les conclusions sur le glissement susceptible de se produire par suite de séismes dans le cas de différents types de matériaux de construction et pour des secousses sismiques d'intensités différentes. Enfin. l'article masse en revue les méthodes dont on disposepour évaiuer la stabilité et les déformations des talus d'un barrage suite à des secousses sismiques, et indique leurs applications possibles. If fait état de conclusions relatives à l'importance du type de sol utilisé pour la construction et à l'éventualité d'un retard de la rupture, une fois que les mouvements de terrain dus aux séismes ont cessé, en raison d'une redistribution de la pression de l'eau interstitielle au sein du remblai. On trouvera des suggestions relatives au rôle que devraient jouer les méthodes analytiques au niveau de l'évaluation globale de la stabilité sismique de barrages, et un exposé des incertitides que cornportent ces méthodes.

A Screen Analysis Procedure for Seismic Slope Stability

“…• The limiting displacements used by Seed (1979) and Hynes-Griffin and Franklin (1984) for earth dams were on the order of 100 cm. The limiting displacements used by for landfills were 15 to 30 cm, which is similar to an earlier 15 cm value recommended by Seed and Bonaparte (1992).…”

“…Seed (1979) calibrated his pseudo-static approach using Newmark displacements calculated with simplified methods (e.g., Makdisi and Seed 1978). The Makdisi and Seed simplified procedure, in turn, is based on a limited number of calculations that were used to relate Newmark displacement to earthquake magnitude and k y /k max (e.g., five calculations for Mϭ6.5, two for Mϭ7.5, and two for Mϭ8.25).…”

“…The Makdisi and Seed simplified procedure, in turn, is based on a limited number of calculations that were used to relate Newmark displacement to earthquake magnitude and k y /k max (e.g., five calculations for Mϭ6.5, two for Mϭ7.5, and two for Mϭ8.25). Seed's (1979) recommendations are an important milestone, as they represent perhaps the first calibration of a pseudo-static method to a particular level of slope performance as indexed by displacement. This concept underlies other widely used screen analysis procedures that have been developed to date, and is retained as well in the present work.…”

“…Since the Seed (1979) work, additional screen analysis procedures have been developed for application to earth dams and solid waste landfills. A procedure for earth dams was developed by Hynes-Griffin and Franklin (1984) based on (1) calculations of shaking within embankment sections using a linear elastic shear beam model by Sarma (1979) and (2) calculations of Newmark displacement from time histories using the analysis approach of Franklin and Chang (1977).…”

Seismic stability analysis of rock slopes by yield design theory using the generalized Hoek-Brown criterion

“…To simulate the potential inertia forces due to ground accelerations in an earthquake, horizontal and vertical static seismic forces are introduced. These forces are assumed to be proportional to the applied forces times horizontal and vertical average seismic coefficients K h and K v [26].…”