Laboratory Simulation of Bentonite Erosion by Downslope Flow on a GCL
Publication: Journal of Geotechnical and Geoenvironmental Engineering
Volume 140, Issue 8
Abstract
Under some circumstances, leaving a composite geomembrane/geosynthetic clay liner (GCL) exposed to solar radiation in the field has been shown to cause shrinkage of the underlying GCL. Recent field studies have shown that leaving a composite liner exposed can also lead to erosion of bentonite from the GCL due to downslope moisture migration. This paper reports an experimental technique that reproduced similar erosion in the laboratory on a typical landfill side slope of . The test method simulates the features that occur with the erosion of bentonite caused by downslope migration of evaporative water in the field. The laboratory tests demonstrate that erosion features can be present but may not be visible unless the appropriate back lighting is used. Erosion features measuring over 25 mm in width were produced. The test method simulated the features that were observed with bentonite erosion in the field and has the potential for use in examining other factors that may affect this type of erosion. The test method developed can be used for examining the response of GCLs when part of a composite liner that will be left exposed. The findings from this laboratory study provide additional motivation for timely covering of composite liner systems as recommended by GCL manufacturers.
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Acknowledgments
Funding for the development of the research infrastructure was provided by the Canada Foundation for Innovation, the Ontario Innovation Trust, the Ontario Research Fund Award, and Queen’s University. The research was funded by the Natural Sciences and Engineering Research Council of Canada. The support of the Killam Trust in the form of a Killam Fellowship to Dr. Rowe is gratefully acknowledged. This investigation into the long-term performance of geosynthetic liner systems is being conducted in partnership with Terrafix Geosynthetics, Terrafix Environmental Technologies, TAG Environmental, Naue, GSE, Solmax International, Ontario Ministry of the Environment, AECOM, AMEC Earth and Environmental, Golder Associates, and the CTT Group. The assistance of Amy Rentz with the development of the classifications in Table 3 and the LED photography is gratefully acknowledged.
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Information & Authors
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Published In
Journal of Geotechnical and Geoenvironmental Engineering
Volume 140 • Issue 8 • August 2014
Copyright
© 2014 American Society of Civil Engineers.
History
Received: Jan 2, 2014
Accepted: Apr 14, 2014
Published online: May 6, 2014
Published in print: Aug 1, 2014
Discussion open until: Oct 6, 2014
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