3D Numerical Modeling of Dynamic Instability Induced by Liquefaction in Loose Sand Deposit when Earthquake Occurs Perpendicular to the Slope

Nazari Tileki, Ali | 2017

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 50342 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Pak, Ali
  7. Abstract:
  8. Soil liquefaction occurring in loose saturated sand deposits during seismic loadings is one of the most destructive earthquake-induced phenomena in the field of earthquake geotechnical engineering. Catastrophic destructions due to this phenomenon that have been observed in the earthquakes such as Kobe (1995), Chi-Chi (1999), etc. has led to extensive studies in this field. In case of soil slopes prone to liquefaction hazard, detailed analysis of this phenomenon requires considering soil-related factors (e.g. shear strength, relative density, permeability, slope geometry) on the one hand, and earthquake-related characteristics (e.g. amplitude, frequency, duration) on the other. Numerical simulation of liquefaction requires solving several differential equations with specific boundary conditions. So far, most of the conducted studies have used the assumption of seismic wave direction being parallel to the slope direction. In this study, the seismic response of loosely deposited saturated sand slopes to seismic waves perpendicular to the direction of the slope is investigated. The applied numerical scheme was first verified via simulation of the well-known VELACS experiments (i.e. VELACS 1 and VELACS 2) tests. Then 3D. fully-coupled dynamic analyses were carried out using the open-source code Opensees by implementing appropriate constitutive models to simulate the non-linear behavior of porous saturated media under various drainage conditions. The results of this study indicated that due to the probability of earthquake occurrence in different directions, it is necessary to consider the effects of seismic waves in both directions on the stability of slopes because the analyses show that in some cases the possibility of liquefaction occurrence under the waves in the direction perpendicular to slope direction is high and cannot be ignored
  9. Keywords:
  10. Liquefaction ; Numerical Modeling ; Earthquake Load ; Three Dimensional Numerical Modeling ; Three Dimentional Fully-Coupled Dynamic Analysis ; Slope Direction

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