Saturated soil cover on liner question

October 1, 2015  |  News, Q&A: GMA Techline

Questions and answers from the GMA Techline. I need your advice on a reservoir we are designing. It is an irrigation reservoir with a 40-mil HDPE geomembrane liner on a 3:1 slope. The client wants to cover the liner with 1ft of silt loam soil. The water elevation in the reservoir will fluctuate abou…
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Geotextile data

October 1, 2015  |  News, Q&A: GMA Techline

Flammability? Zip ties? MARV? Ponds? GT specs? Questions and answers from the GMA Techline. I am a student of hydraulic structures and I need some data about transmissivity of geotextiles (ASTM D4716 or ISO/DIS 12958); and also permittivity or cross-plane permeability (ASTM D5493 or every valid stan…
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Protrusion/particle shape—geotextile cushions

October 1, 2015  |  News, Q&A: GMA Techline

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 geomem…
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Zip-tie strength

October 1, 2015  |  News, Q&A: GMA Techline

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

October 1, 2015  |  News, Q&A: GMA Techline

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 whil…
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Nonwoven needle-punched GT

October 1, 2015  |  News, Q&A: GMA Techline

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 co…
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Effluent pond liners

October 1, 2015  |  News, Q&A: GMA Techline

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 betwee…
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GCL woven side against geomembrane

October 1, 2015  |  News, Q&A: GMA Techline

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…
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HDPE flammability

October 1, 2015  |  News, Q&A: GMA Techline

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,…
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Stormwater detention pond

June 1, 2015  |  News, Q&A: GMA Techline

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 …
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