In late 2019, the GeoEngineering Centre posted a video presentation from Queen’s University PhD student Vanessa Di Battista. The topic, “GCLs and Antarctica: Effects of Subgrade on Hydration and Desiccation,” builds nicely on work Queen’s researchers have been involved in at Antarctica’s Casey Station for many years.
Di Battista spent a couple work season at the station.
Geosynthetic clay liners (GCLs) have been there in remediation works with contaminated soils. Geosynthetic liners and covers have been used to encapsulate contaminated soil in biopiles. The piles enable native soil microorganisms to break down the contaminants during the few warm months in which the microbes are active.
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GCL HYDRATION & DESICCATION
“One thing that really stuck out to me was the variability of moisture content of our samples,” Di Battista says.
She had exhumed samples from a relatively small area but found a tremendous range of values, from desiccation as low as 21% moisture content to hydration as strong as 191% moisture content. The hydraulic conductivity of the most desiccated sample was 5.2 x 10-11.
“Even though it is an increase [versus virgin numbers], it’s still a relatively good number. This GCL would probably perform well in the field.”
Her research then turned to focusing on the GCL hydration and how to manage the varying hydration conditions in Antarctica’s cold desert environment.
“We noticed that our GCLs were overlying sharp and jagged rocks,” Di Battista notes. “We know that the quality of subgrade has a large effect on the quality of our GCL hydration.”
Watch the video above to learn about the GCL hydration test plots used to analyze different installation set ups, including with geotextile separators and geotextiles and geomembranes under the GCL.
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