SEISMIC SAFETY ANALYSIS OF SLOPES
Abstract
To obviate the complicated calculation of progressive failure to stress-strain approach and the inaccuracy of traditional pseudo static analysis in seismic slope stability analysis, it requires an effective method which can directly determine critical state of the slope and explicitly account for the effects of earthquake on the slope stability. The present research effort is an attempt to develop a model to evaluate the critical state and subsequently the necessary calculation of effects of earthquake in slopes based on the framework of conventional pseudo-static analysis. The upper bound techniques of pseudo-static limit analysis are applied for the determination of critical state of slopes, in this case, the yield acceleration and its corresponding failure mechanism. Based on the calculated yield acceleration and the critical failure surface, Newmark's analytical procedure is then used to assess the soil displacements of slopes, which are subjected to a given earthquake load. However, neither the pseudo-static method nor Newmark's analytical procedure can account for the dynamic effects of pore water pressures built-up and possible loss of shear strength of soil owing to liquefaction during earthquake. In these early studies, the potential failure surface in a slope is assumed not shifted and the shear resistance along this surface is to be constant during the earthquake. Actually, after several cycles of shaking due to the possible occurrence of liquefaction in the slopes, the failure surface need to be decided by a number of trials. Finally, this study concerns the investigation of the liquefaction potential as well as the determination of critical failure surfaces of slopes and its associated displacement after each specified cycles of loading during earthquake. A computer program is developed for the analysis of seismic slope stability. Typical numerical results and comparisons between those which considering liquefaction and ignoring liquefaction are presented.
Degree
Ph.D.
Subject Area
Civil engineering|Cartography
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