Location

Arlington, Virginia

Session Start Date

8-11-2008

Session End Date

8-16-2008

Abstract

The first presented case history is the construction of a new federal road south of Berlin, Germany. An embankment has been designed to cross a region of very soft peat soil with underlying organic silt, sand and boulder clay, with a total length of about 140 m. Ground improvement using sand columns with a diameter of 0.6 m and a distance of 1.5 m were designed and applied to all regions with more than 2.5 m thickness of the organic soil layer. Geogrids were used in addition to the vertical sand columns to take into account the action of horizontal forces beneath the embankment. The measured settlements as well as the tensile strains in the geogrids show the significant creep behaviour of organic soils over very long periods of time. The second case history is the renewal and enlargement of a federal expressway resting on very soft organic soils. Extensive laboratory tests as well as a large scale model test in a geotechnical testing pit using in situ excavated organic silt have been done to investigate the soilcolumn interaction behaviour in more detail. The data confirm that the long term deformations of the organic soils are mainly influenced by the creep behaviour of these soils.

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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Design and Construction of Granular Soil Columns for Ground Improvement of Very Soft Soils for Road Embankments

Arlington, Virginia

The first presented case history is the construction of a new federal road south of Berlin, Germany. An embankment has been designed to cross a region of very soft peat soil with underlying organic silt, sand and boulder clay, with a total length of about 140 m. Ground improvement using sand columns with a diameter of 0.6 m and a distance of 1.5 m were designed and applied to all regions with more than 2.5 m thickness of the organic soil layer. Geogrids were used in addition to the vertical sand columns to take into account the action of horizontal forces beneath the embankment. The measured settlements as well as the tensile strains in the geogrids show the significant creep behaviour of organic soils over very long periods of time. The second case history is the renewal and enlargement of a federal expressway resting on very soft organic soils. Extensive laboratory tests as well as a large scale model test in a geotechnical testing pit using in situ excavated organic silt have been done to investigate the soilcolumn interaction behaviour in more detail. The data confirm that the long term deformations of the organic soils are mainly influenced by the creep behaviour of these soils.