Location

Arlington, Virginia

Session Start Date

8-11-2008

Session End Date

8-16-2008

Abstract

Two highway bridge approaches, about 10 and 12 m in height, near Calcutta, India constructed with mechanically stabilized earth failed recently. These embankments were founded on soft and compressible, fine-grained soils of the intertidal flats and backswamps of the Ganges delta. One of these embankments, which failed in the final stages of its construction, was constructed after foundation soils were strengthened with preloading and prefabricated vertical drain installation and the other second embankment that failed within a month of its opening for traffic was constructed on unimproved ground. Fortunately, direct collateral damage from these incidents was small. Available geotechnical data indicated that design inadequacy was the main cause of these failures. Using pre- and post- consolidation shear strengths the embankments were redesigned. Reconstruction involved PVD installation at the second site and construction of stabilizing berms at both locations. The facilities are now operational and appear to be performing satisfactorily. Details of the failures, post failure investigations and monitoring, and redesign are presented in the paper.

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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Failure of Two High Embankments at Soft Soil Sites

Arlington, Virginia

Two highway bridge approaches, about 10 and 12 m in height, near Calcutta, India constructed with mechanically stabilized earth failed recently. These embankments were founded on soft and compressible, fine-grained soils of the intertidal flats and backswamps of the Ganges delta. One of these embankments, which failed in the final stages of its construction, was constructed after foundation soils were strengthened with preloading and prefabricated vertical drain installation and the other second embankment that failed within a month of its opening for traffic was constructed on unimproved ground. Fortunately, direct collateral damage from these incidents was small. Available geotechnical data indicated that design inadequacy was the main cause of these failures. Using pre- and post- consolidation shear strengths the embankments were redesigned. Reconstruction involved PVD installation at the second site and construction of stabilizing berms at both locations. The facilities are now operational and appear to be performing satisfactorily. Details of the failures, post failure investigations and monitoring, and redesign are presented in the paper.