Numerical Study on the Effects of Liquefaction Induced Lateral Spreading on Rigid Waterfront Structures

Khosrojerdi, Mahsa | 2013

467 Viewed
  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 44926 (09)
  4. University: Sharif University of Technology
  5. Department: Civil Engineering
  6. Advisor(s): Pak, Ali
  7. Abstract:
  8. Lateral Spreading, which usually occurs as a consequence of liquefaction in gently sloped loose saturated sand layers, is known to be a major source of earthquake-induced damages to structures such as bridge piers, quay walls, pipelines and highway/railway. Therefore, evaluation of liquefaction potential and using appropriate methods for prediction of the adverse events of lateral spreading is of great importance. In this study, numerical modeling has been used to study of lateral spreading phenomenon behind rigid waterfront structures. In order to perform a numerical modeling of lateral spreading and also designing the structures exposed to its effects, the interaction of the soil solid phase with the pore fluid phase should be considered in the solution of the coupled differential equations of the load equilibrium and fluid flow continuity.In this study, a fully coupled finite element code “PISA” utilizing a critical state two-surface plasticity constitutive model, proposed by Manzari and Dafalias (1997), has been applied to numerically simulate the behavior of sands and to evaluate the magnitude of deformations occurred in liquefiable soils. This constitutive model has the ability to simulate the drained or undrained behavior of saturated sands under monotonic and cyclic loading. Using a variable permeability function with respect to excess pore pressure ratio is another distinctive feature of the current study.In order to be confident of the accuracy of numerical analysis results, at first several monotonic and cyclic triaxial experiments under drained and undrained conditions were simulated and the results of numerical analysis compared with experimental observations. Furthermore, the developed code has been verified against the results of two centrifuge experiments, VELACS 1& 2. These comparisons show that the applied numerical program has the capability to accurately simulate the “liquefaction” and “lateral spreading” phenomena.After getting confidence of the accuracy of the results, this model has been used to evaluate the effects of liquefaction and lateral spreading on waterfront structures by conducting a numerical study about the seismic behavior of gravity quay walls in saturated sandy soil -by modeling VELACS11 experiment- and shallow foundations placed on saturated soils -by modeling VELACS 12 experiment.Comparison of this the results of this study with experimental ones shows the proficiency of this numerical study to other similar studies in precise predicting of the magnitude of soil deformations and generated excess pore water pressure behind rigid waterfront structures and gravity quay walls during earthquake
  9. Keywords:
  10. Liquefaction ; Fully Coupled Two-Dimensional Dynamics Analysis ; Numerical Modeling ; Liquefaction-Induced Lateral Spreading ;

 Digital Object List