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Drainage geocomposite

October 1, 2008

From the GMA Techline Subject: Drainage geocomposite— I have to test drainage geocomposite material regarding friction behavior and internal shear strength. In terms of references, I see 2 options: friction test (drain material/soil), according to ASTM D5321; and internal shear strength, according to ASTM D5321. I know that for friction test of drainage material, it …

How long will my liner last?

What is the remaining service life of my HDPE geomembrane? By Ian D. Peggs, P.E., P.Eng., Ph.D. Introduction In his keynote lecture at the GeoAmericas-2008 conference last March, Dr. Robert Koerner (et al., 2008) of the Geosynthetic Institute (GSI) reported the ongoing Geosynthetic Research Institute (GRI) work to make the first real stab at assessing …

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Geotextiles in dams: Forging federal guidelines

August 1, 2008

By Douglas A. Crum Abstract The major building era for large dams in the United States, from the 1940s to the 1970s, ended about the time geotextiles were becoming popular. For the last 40-plus years, geotextiles have been used in many dams worldwide for various applications. During this period, federal agencies have resisted experimentation with …

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Active LFG control: An unreliable aid to veneer stability

June 1, 2008

By Gregory N. Richardson, Stacey A. Smith, and Pieter K. Scheer Abstract The potential for sliding failure of final covers and piggyback liners in municipal solid waste (MSW) landfills equipped with active landfill gas (LFG) control systems is demonstrated and the need for a contingency passive venting system is presented. Two final cover failures illustrate …

Celebrating a decade of GSI/GRI polyolefin specs

By Bob Koerner From the very beginning of the GSI/ GRI consortium in 1986, it was recognized that specific focus groups were the way to initiate individual programs and documents. After a draft document is eventually established within a group, the entire membership is then brought into the activity for modification and eventual agreement. This …

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Slack calculations

April 1, 2008

From the GMA Techline Subject: Slack calculations — Do you have a reference that discusses the impact of environmental conditions and the procedures for determining “slack” into an HDPE liner at the time of installation? (Rod, California) Reply: The subject of calculating slack in geomembranes for the purpose of backfilling, and then having the lower …

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A forensic hypothetical: The case of the percolating water

By Dov Leshchinsky Introduction Nearly every SRW system in the market has experienced some sort of failure. Like the power of chum in luring sharks, failures attract attorneys and engineering experts. Typically, the attorney for the plaintiff will compile “expert” reports providing a list of what appear to be the faults in design and/or construction. …

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The GRS bridges of Defiance County

By Michael Adams Introduction Three years ago, the Federal Highway Administration (FHWA) teamed up with local officials in Defiance County, Ohio, to test a new prototype geosynthetic-reinforced soil (GRS) integrated bridge system. Built in 2005, the prototype GRS bridge on Bowman Road in Defiance County is a success story for the county as well as …

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Geomembrane thickness

From the GMA Techline Subject: Geomembrane thickness— We have been designing an ash pond for a thermal- electric plant, where we intend to use an HDPE geomembrane for the lining system. Can you recommend what thickness we should use for safety reasons, as our project is located near Halong Bay [in northeast Vietnam]? Do you …

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GRI Standards

From the GMA Techline Subject: GRI Standards — I am seeing references to GRI Standards GM 10, GM 14, and GM 18 in a project spec for a facility that will be under construction soon. There are other references too, of course, but these I’ve listed are not current, according to your Web site. Please …