Location

New York, New York

Session Start Date

4-13-2004

Session End Date

4-17-2004

Abstract

The construction of the road fixed-link crossing between Preveza and Aktio on the north-western coast of Greece has recently been completed. The project consists of an immersed single-tube tunnel under the strait and two cut-and-cover tunnels at the ends of the immersed part. The immersed section is constructed of eight precast rectangular concrete elements placed on the sea bottom at a depth of 25 m. The site is characterized by high seismicity. Foundation soil consists of Holocene marine sediments comprising irregular layers of sands, silts and clays that extend to great depth in the central part of the strait. Along the entire tunnel alignment the silty sands and sandy silts of the top layers are classified as potentially liquefiable due to their low density. Soil improvement in the form of stone columns has been carried out below the tunnel foundation for reducing risk from liquefaction. The soil conditions and the seismic input parameters are presented and an overview of the extensive dynamic laboratory testing program conducted is given. The seismic site response analyses performed for determining the depth of ground improvement are summarized. The design of the stone columns as well as a practical method for estimating the stiffness of the composite soil are described.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conference on Case Histories in Geotechnical Engineering

Meeting Name

Fifth Conference

Publisher

University of Missouri--Rolla

Publication Date

4-13-2004

Document Version

Final Version

Rights

© 2004 University of Missouri--Rolla, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Apr 13th, 12:00 AM Apr 17th, 12:00 AM

Stone Column Ground Improvement Against Liquefaction for the Preveza-Aktio Immersed Tunnel

New York, New York

The construction of the road fixed-link crossing between Preveza and Aktio on the north-western coast of Greece has recently been completed. The project consists of an immersed single-tube tunnel under the strait and two cut-and-cover tunnels at the ends of the immersed part. The immersed section is constructed of eight precast rectangular concrete elements placed on the sea bottom at a depth of 25 m. The site is characterized by high seismicity. Foundation soil consists of Holocene marine sediments comprising irregular layers of sands, silts and clays that extend to great depth in the central part of the strait. Along the entire tunnel alignment the silty sands and sandy silts of the top layers are classified as potentially liquefiable due to their low density. Soil improvement in the form of stone columns has been carried out below the tunnel foundation for reducing risk from liquefaction. The soil conditions and the seismic input parameters are presented and an overview of the extensive dynamic laboratory testing program conducted is given. The seismic site response analyses performed for determining the depth of ground improvement are summarized. The design of the stone columns as well as a practical method for estimating the stiffness of the composite soil are described.