Location

Arlington, Virginia

Session Start Date

8-11-2008

Session End Date

8-16-2008

Abstract

Coquitlam Dam, constructed in the early 1910s, is a 30 m high hydraulic fill embankment. The dam is situated in a region of high seismic hazard in British Columbia, Canada. The existing dam core and shells, and part of the dam foundation are deemed to be liquefiable under the design earthquake. A new 30 m high compacted earth core rockfill embankment dam is currently being constructed at the downstream toe of the existing dam. As part of the construction of the new dam, a seepage cutoff wall has been completed underneath the central core of the new embankment to control foundation seepage gradients and to minimize piping potential of the foundation soils. The wall was constructed of plastic concrete using slurry panel construction method. Plastic concrete was selected to provide a seepage cutoff wall that has sufficient strength to withstand both static and seismic stresses beneath the new embankment, and yet is flexible enough to undergo seismic deformations, without cracking, with the surrounding soils. This paper describes the construction of the plastic concrete cutoff wall for the new Coquitlam dam, including the field and laboratory testing performed to confirm design wall stiffness, strength, and hydraulic conductivity requirements. The trial laboratory and field testing programs to determine plastic concrete mix design, and the QA/QC testing conducted during construction, including measurement of in-situ hydraulic conductivity of the constructed plastic concrete panels, are presented.

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

Construction of a Plastic Concrete Seepage Cutoff Wall for the New Coquitlam Dam

Arlington, Virginia

Coquitlam Dam, constructed in the early 1910s, is a 30 m high hydraulic fill embankment. The dam is situated in a region of high seismic hazard in British Columbia, Canada. The existing dam core and shells, and part of the dam foundation are deemed to be liquefiable under the design earthquake. A new 30 m high compacted earth core rockfill embankment dam is currently being constructed at the downstream toe of the existing dam. As part of the construction of the new dam, a seepage cutoff wall has been completed underneath the central core of the new embankment to control foundation seepage gradients and to minimize piping potential of the foundation soils. The wall was constructed of plastic concrete using slurry panel construction method. Plastic concrete was selected to provide a seepage cutoff wall that has sufficient strength to withstand both static and seismic stresses beneath the new embankment, and yet is flexible enough to undergo seismic deformations, without cracking, with the surrounding soils. This paper describes the construction of the plastic concrete cutoff wall for the new Coquitlam dam, including the field and laboratory testing performed to confirm design wall stiffness, strength, and hydraulic conductivity requirements. The trial laboratory and field testing programs to determine plastic concrete mix design, and the QA/QC testing conducted during construction, including measurement of in-situ hydraulic conductivity of the constructed plastic concrete panels, are presented.