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The GMA Techline

April 1st, 2019

Vegetation causing gases under geomembrane? Q: I have a site where we are installing a high-density polyethylene (HDPE) liner in an existing pond. Because of some residual heavy metals in the top layer of soil, I would like to strip off the top 3–6 inches (7.6–15.2 cm) of soil and vegetation. Alternatively, we could mow and […]

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The GMA Techline

October 1st, 2018

Toxicity of nonwovens? Q: Are there any comprehensive tests (or a general synopsis) of the environmental toxicity of leachate from nonwoven polypropylene fabrics when aged in a freshwater or saltwater solution? Regulatory and municipal bodies in Europe and New Zealand are requesting more info about products that are used in riparian and coastal environments. A: […]

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Geosynthetics opportunities and solutions in shale gas extraction

October 1st, 2018

While natural gas contained within shale rock is geologic and thus ancient by its very nature, the practice of its removal by horizontal drilling coupled with hydrofracking is a relatively recent development (Figure 1). Indeed, these dual technologies are making possible the recovery of huge amounts of natural gas—so much so that one can envision […]

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The GMA Techline answers all

August 1st, 2018

UV Weathering of Geotextiles Q: My firm is providing construction quality assurance services for a landfill cell expansion. We are having an issue with our contractor and are going to be in a position of having 8 ounces/square yard (271 g/m2) of nonwoven geotextile exposed for a period of time, which exceeds the seven-day limit […]

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The durability of exposed geomembrane covers

October 1st, 2017

The most frequently asked question by people in the geosynthetics world is how long is the anticipated lifetime of geosynthetics. So much so that of the more than 3,000 questions submitted to the GMA Techline since it began in 2004, 591 (19.7%) have been on lifetime, aka durability. Of these, 49% were on buried lifetime, […]

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Questions and answers from the GMA Techline

February 1st, 2017

Spraying? Shear Strength? Hydraulics? [A more] non-permeable GT? Q: I have received an inquiry for a non-permeable geotextile, which is UV-resistant and will be installed on a long slope for erosion control. Could you kindly recommend a product that would meet these requirements or a solution for this application? Your assistance with this is much […]

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