Location

Chicago, Illinois

Session Start Date

4-29-2013

Session End Date

5-4-2013

Abstract

In the winter of 2010, a landslide occurred on Egnatia motorway affecting an embankment approximately 300m long and 8–20 m high. The crest of the slide was at a distance of 60m uphill from the highway and the maximum depth of movement was 28 m. The bedrock in the area consists of alternating layers of siltstone and sandstone with local conglomerate intercalations covered by a soil layer of variable thickness (up to 30m) and consistency. The sliding occurred within a zone of plastic red clay just above bedrock exhibiting strength parameters between peak and residual values. A horizontal movement of 30cm was recorded with an initial rate of up to 15mm/day measured in the numerous inclinometers that were installed. Immediate measures were adopted consisting of dewatering through pumping wells constructed in the central reserve between the two carriageways and unloading through earth removal from the crest of the sliding mass. These measures resulted in a significant mitigation of the movement allowing for the design and construction of permanent stabilizing measures (mainly shear keys) whilst the motorway remained under continuous operation. A staged approach was applied in the design and construction of the remedial works based on the constant monitoring of the slide behavior through inclinometers. The paper describes the sliding event and the actions taken to deal with the emergency. It presents the geotechnical model and the geometry of the sliding based on the results of the geotechnical investigation and the extensive network of instruments that were installed. It discusses the alternatives examined and the stabilization measures that were designed and eventually implemented. Finally, it outlines the construction sequence and assesses the effectiveness of the stabilization measures to date based on the geotechnical instrument monitoring.

Department(s)

Civil, Architectural and Environmental Engineering

Appears In

International Conference on Case Histories in Geotechnical Engineering

Meeting Name

Seventh Conference

Publisher

Missouri University of Science and Technology

Publication Date

4-29-2013

Document Version

Final Version

Rights

© 2013 Missouri University of Science and Technology, All rights reserved.

Document Type

Article - Conference proceedings

File Type

text

Language

English

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Apr 29th, 12:00 AM May 4th, 12:00 AM

Stabilizing a Landslide on a Highway Under Traffic: A Case History on Egnatia Motorway in Greece

Chicago, Illinois

In the winter of 2010, a landslide occurred on Egnatia motorway affecting an embankment approximately 300m long and 8–20 m high. The crest of the slide was at a distance of 60m uphill from the highway and the maximum depth of movement was 28 m. The bedrock in the area consists of alternating layers of siltstone and sandstone with local conglomerate intercalations covered by a soil layer of variable thickness (up to 30m) and consistency. The sliding occurred within a zone of plastic red clay just above bedrock exhibiting strength parameters between peak and residual values. A horizontal movement of 30cm was recorded with an initial rate of up to 15mm/day measured in the numerous inclinometers that were installed. Immediate measures were adopted consisting of dewatering through pumping wells constructed in the central reserve between the two carriageways and unloading through earth removal from the crest of the sliding mass. These measures resulted in a significant mitigation of the movement allowing for the design and construction of permanent stabilizing measures (mainly shear keys) whilst the motorway remained under continuous operation. A staged approach was applied in the design and construction of the remedial works based on the constant monitoring of the slide behavior through inclinometers. The paper describes the sliding event and the actions taken to deal with the emergency. It presents the geotechnical model and the geometry of the sliding based on the results of the geotechnical investigation and the extensive network of instruments that were installed. It discusses the alternatives examined and the stabilization measures that were designed and eventually implemented. Finally, it outlines the construction sequence and assesses the effectiveness of the stabilization measures to date based on the geotechnical instrument monitoring.