Location

Arlington, Virginia

Session Start Date

8-11-2008

Session End Date

8-16-2008

Abstract

Liquefaction of water-saturated sandy soils remains a major concern in geotechnical earthquake engineering. Experience from past earthquakes indicates that large lateral spreads and flow slides in sand deposits have taken place in coastal and river areas not only during shaking but also some time after earthquake shaking ceases. The ground slopes in these slides were often gentler than a few percent. Recent research including physical model tests and numerical investigations indicates that the presence of a low permeability silt or clay layer as a hydraulic barrier may be responsible for some of the historical and seemingly unexplainable landslides. This paper describes the results of a coupled stress-flow analysis carried out for a near-shore LNG import terminal to be founded on a moderate submarine slope comprising a liquefiable sand layer overlain by a clay layer located in a region with moderate seismic risk (PGA< 0.15g). Artesian water conditions are present at the site due to the presence of the hydraulic barrier layer and the mountain slopes near the shoreline. An effective-stress based approach was employed to analyze the excess pore pressure generation in the sand layer associated with earthquake loading. The analyses showed that pore pressure redistribution during and after earthquake shaking may result in continued displacements after shaking has ceased, although the magnitude of displacements at the end of shaking was not very large.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conference on Case Histories in Geotechnical Engineering

Meeting Name

Sixth Conference

Publisher

Missouri University of Science and Technology

Publication Date

8-11-2008

Document Version

Final Version

Rights

© 2008 Missouri University of Science and Technology, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Aug 11th, 12:00 AM Aug 16th, 12:00 AM

Prediction of Post-Earthquake Failure for a Near-Shore Slope in a Low Seismic Region

Arlington, Virginia

Liquefaction of water-saturated sandy soils remains a major concern in geotechnical earthquake engineering. Experience from past earthquakes indicates that large lateral spreads and flow slides in sand deposits have taken place in coastal and river areas not only during shaking but also some time after earthquake shaking ceases. The ground slopes in these slides were often gentler than a few percent. Recent research including physical model tests and numerical investigations indicates that the presence of a low permeability silt or clay layer as a hydraulic barrier may be responsible for some of the historical and seemingly unexplainable landslides. This paper describes the results of a coupled stress-flow analysis carried out for a near-shore LNG import terminal to be founded on a moderate submarine slope comprising a liquefiable sand layer overlain by a clay layer located in a region with moderate seismic risk (PGA< 0.15g). Artesian water conditions are present at the site due to the presence of the hydraulic barrier layer and the mountain slopes near the shoreline. An effective-stress based approach was employed to analyze the excess pore pressure generation in the sand layer associated with earthquake loading. The analyses showed that pore pressure redistribution during and after earthquake shaking may result in continued displacements after shaking has ceased, although the magnitude of displacements at the end of shaking was not very large.