Location
Arlington, Virginia
Date
14 Aug 2008, 4:30pm - 6:00pm
Abstract
The safety of buried pipelines during earthquakes has involved a great deal of attention in last few years. Important characteristics of buried pipelines are that they cover large areas and can be subjected to a variety of geotectonic hazards. Earthquake damages to buried pipelines can be attributed to transient ground deformations (TGD), permanent ground deformations (PGD) or both. PGD occurs as a result of surface faulting, liquefaction, landslides, and differential settlement from consolidation of cohesionless soil. To evaluate seismic behavior of buried pipelines subjected to large values of permanent ground deformations, appropriate non-linear cyclic stress-strain relationship should be implemented in any numerical method. Among the phenomena, which cause permanent ground deformations, the settlement and lateral spreading induced by liquefaction are considered as the main cause of damage in buried structures. Therefore, this study is aimed to take into account the potential of liquefaction during an earthquake into the numerical analysis of buried pipelines using FEM. During the earthquake, the soil volume and also pore-pressure water is changed and therefore as saturated loose sands undergo simple shear deformations, the stiffness at any time is changed as the function of mean normal effective stress. In this study, a hypo-elastic model is adopted for the soil to evaluate changes in the pore pressures and also effective stresses during the excitation. In a finite element modeling, for the areas not expecting the liquefaction to occur, the pipe is modeled using beam elements and soil is modeled by some bi-linear springs; while for liquefied areas, the pipe is modeled by shell elements and solid elements are used to model the surrounding soil.
Department(s)
Civil, Architectural and Environmental Engineering
Meeting Name
6th Conference of the International Conference on Case Histories in Geotechnical Engineering
Publisher
Missouri University of Science and Technology
Document Version
Final Version
Rights
© 2008 Missouri University of Science and Technology, All rights reserved.
Creative Commons Licensing
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.
Document Type
Article - Conference proceedings
File Type
text
Language
English
Recommended Citation
Halabian, Amir M.; Hashemolhosseini, S. Hamid; and Rezaei, Mehdi, "Nonlinear Seismic Analysis of Buried Pipelines During Liquefaction" (2008). International Conference on Case Histories in Geotechnical Engineering. 11.
https://scholarsmine.mst.edu/icchge/6icchge/session04/11
Nonlinear Seismic Analysis of Buried Pipelines During Liquefaction
Arlington, Virginia
The safety of buried pipelines during earthquakes has involved a great deal of attention in last few years. Important characteristics of buried pipelines are that they cover large areas and can be subjected to a variety of geotectonic hazards. Earthquake damages to buried pipelines can be attributed to transient ground deformations (TGD), permanent ground deformations (PGD) or both. PGD occurs as a result of surface faulting, liquefaction, landslides, and differential settlement from consolidation of cohesionless soil. To evaluate seismic behavior of buried pipelines subjected to large values of permanent ground deformations, appropriate non-linear cyclic stress-strain relationship should be implemented in any numerical method. Among the phenomena, which cause permanent ground deformations, the settlement and lateral spreading induced by liquefaction are considered as the main cause of damage in buried structures. Therefore, this study is aimed to take into account the potential of liquefaction during an earthquake into the numerical analysis of buried pipelines using FEM. During the earthquake, the soil volume and also pore-pressure water is changed and therefore as saturated loose sands undergo simple shear deformations, the stiffness at any time is changed as the function of mean normal effective stress. In this study, a hypo-elastic model is adopted for the soil to evaluate changes in the pore pressures and also effective stresses during the excitation. In a finite element modeling, for the areas not expecting the liquefaction to occur, the pipe is modeled using beam elements and soil is modeled by some bi-linear springs; while for liquefied areas, the pipe is modeled by shell elements and solid elements are used to model the surrounding soil.
