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Protrusion/particle shape—geotextile cushions

October 1, 2015

Flammability? Zip ties? MARV? Ponds? GT specs? Questions and answers from the GMT Techline. Our landfill liner project specifications require the use of rounded to subangular gravel to be placed as a leachate drainage layer or leachate collection pipe bedding. The gravel is separated from the geomembrane liner by a nonwoven geotextile cushion. During bidding, …

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Zip-tie strength

Flammability? Zip ties? MARV? Ponds? GT specs? Questions and answers from the GMA Techline. We had a problem at one of the construction projects where we were providing CQA. It turned out that the installer had two different types (and apparently strengths) of zip ties. There ended up being seam failures in some of the …

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GRI White Paper #10/Test Method GTI2(A)

Flammability? Zip ties? MARV? Ponds? GT specs? Questions and answers from the GMA Techline. I have reviewed GRI White Paper #10, GRI Test Method GT12(a), ASTM D4354, and ASTM D4759 and have a question. I have reviewed some recent CQA test results of a nonwoven cushion geotextile roll sample and while the average of the …

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Nonwoven needle-punched GT

We specify that the geotextile under riprap must be nonwoven, needle-punched, Class 1. NCHRP Report 568 (page C-25, Section 7.1) requires that nonwoven geotextile filter under riprap must have a mass density greater than 12osy (ounces per square yard). We have the following questions: What is the cost difference between nonwoven needle-punched, Class 1 12osy …

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Effluent pond liners

Flammability? Zip ties? MARV? Ponds? GT specs? Questions and answers from the GMA Techline. I’m designing an effluent pond (the geotechnical aspect at least) and have a couple of questions: Do you see any issues with placing a gravel (rounded) subdrain system underneath the pond, sandwiched between a geomembrane (likely textured HDPE) and a geotextile …

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GCL woven side against geomembrane

Flammability? Zip ties? MARV? Ponds? GT Specs? Questions and answers from the GMA Techline. I seem to recall a webinar or presentation in which the presenter warned against using the woven side of a GCL against a geomembrane due to bentonite squeeze-out and subsequent slippage. Instead, the nonwoven side was recommended against the geomembrane with …

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HDPE flammability

Flammability? Zip yies? MARV? Ponds? GT specs? Questions and answers from the GMA Techline. I am involved with a landfill permit renewal. A question keeps coming up concerning the flammability potential of HDPE liner. What is that potential and do you know of any liner system fires? Eric | USA Eric, HDPE melts between 110 …

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Stormwater detention pond

June 1, 2015

Geomembrane testing? Root penetration? Welding HDPE with LLDPE? Woven geopipe? Questions and answers from the GMA Techline We are designing a campus that has a pond for stormwater detention, as well as an architectural/aesthetic pond that is about an acre in area, 6 feet deep, sideslopes 4H:1V, and is right up against a building. The …

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Woven Geopipe?

Geomembrane testing? Root penetration? Welding HDPE with LLDPE? Woven geopipe? Questions and answers from the GMA Techline We hope you can give us contacts for some fabricators who could supply geosynthetic pipe or equal. We want to make woven pipe for water—sizes from 3 to 30 feet and pressures 10 to 100 feet of head. …

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Welding on the slope

Geomembrane testing? Root penetration? Welding HDPE with LLDPE? Woven geopipe? Questions and answers from the GMA Techline I have a colleague who is insisting that we build a pond’s embankment extension by welding new geomembrane to an old one on the “slight” slope (really somewhere 1:4 ratio). I am arguing that we should do welding …