Effects of temperature on geomembrane strength

From the GMA Techline

Subject: Effects of temperature on geomembrane strength— I am working on the design for some lined reservoirs where the liner may be exposed for some time during the summer, with the temperatures possibly approaching 120°F. We plan to use a 60-mil HDPE geomembrane.

Giroud et al. advises that summer and winter temperature effects should be considered in the anchorage design. However, I have been unable to find data regarding changes of strength with temperature.

Can you direct me to where I might obtain this information, or perhaps advise on how these factors are normally considered during design?

Also, do you know if the strength of white geomembrane is less affected by heat than that of black geomembrane? (Greg, California)

Reply: There have been undocumented studies on the temperature dependence of HDPE GMs insofar as their stress vs. strain response is concerned. In general, the higher the temperature, the longer the elongation at break and the lower the strength. The yield point, however, is relatively unaffected..

This is important in your question since we generally design HDPE on the basis of its yield properties. This being the case, I do not know how it would affect an anchorage design. At least in my example in “Designing with Geosynthetics,” it would have no effect.

Thanks for the question and good luck.

Bob Koerner | GMA Techline