GWFV walls and slopes

October 1, 2017

New patented technology is available to construct geosynthetic wrap-face vegetated (GWFV) retaining walls and reinforced soil slopes using a pyramidal-woven, high-performance turf reinforcement mat (HPTRM) in conjunction with fiber-composite internal braces. This wrap-face system eliminates the need for temporary external bracing (formwork) or for facing elements comprised of metallic wire-frame units, which traditionally have served …

Part 1: Controlling uplifting gas bubbles in exposed geomembrane-lined ponds

There is a substantial legacy of literature devoted to the design, construction and operation of geomembrane-lined ponds, with perhaps the best and most complete reference being 34 years old by Giroud (1983). Even with this long history, there continue to be problems and failures with lined ponds. One of the problems continuing to plague the …

The durability of exposed geomembrane covers

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, …

GMA Techline

Welding HDPE to PVC and more Q: I would appreciate any input you have on these questions: Can a high-density polyethylene (HDPE) geomembrane (GM) be welded to a PVC geomembrane? I am looking to connect a geomembrane to a building foundation. Based on some research, I have found the following options: bolt the geomembrane to …

Part 2: The regulation of CCR in the United States: Geosynthetics and barriers

As discussed in Part 1 of “The Regulation of CCR in the United States,” for the first time in decades, nationwide regulation of CCR (coal combustion residuals) surface impoundments expands the regulated use of geosynthetic materials. While the CCR Rule (2015) allows continued operation of existing CCR surface impoundments, it provides criteria for the disposition …

Part 1: The regulation of CCR in the United States: Geosynthetics and barriers

August 1, 2017

The regulation of coal ash (coal combustion residuals or CCR) has significantly expanded the market for geosynthetics within the United States. Further, there is interest in these regulations around the globe in every country using coal as an energy source. These regulations are the result of recent environmental incidents. The regulations call for the increased …

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GMA Techline

Liner repair? Pullout tests? Sewn seams? Shear strength of sludges? Geomembrane liner repair Q: I have a facility that has submitted liner repair documentation for the repair of a high-density polyethylene (HDPE) liner for a leachate/stormwater pond at an industrial landfill site. The repairs were performed using either a patch or, for indentations and small …

CCR management using geotextile tubes

Introduction Since the late 1800s, coal has played a leading role in U.S. production of electrical energy. Coal-fired power plants have provided reliable electrical power from the earliest days when power plants were run with hand-fed coal to heat boilers to produce steam. The introduction of pulverized coal led to improvements in the electrical-generation process …

Using geosynthetics for macroencapsulation for CCR on-site clean closure

Coal combustion residuals (CCR) have been used for many years in the construction of berms and engineered structural fill applications, including embankments for highways, dikes, and levees. However, large, unencapsulated structural fill projects have become a focus of environmental concerns due to potential leaching of metals and structural failures. Cap-in-place of CCR surface impoundments is …

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Achieving zero leaks on a budget with geomembranes

June 1, 2017

For more than 30 years, the geomembrane industry has been told that “all geomembranes leak” (Giroud 1984), as if this were some foregone conclusion no matter what might happen from geomembrane manufacturing to the time it is put into service. But recently, the idea of “zero leaks” has been a hot topic at industry conferences, …