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What’s the word in WRRDA?
June 1st, 2014
By Ron Bygness Geosynthetics! That’s the word all right! For the first time in U.S. history, the phrase “use of geosynthetic materials” is included in an official, passed-by-the-House, passed-by-the-Senate, signed-by-the-president, United-States-of-America law. You can read it yourself right here in the new Water Resources Reform & Development Act (WRRDA) section titled “Use of innovative materials”: […]
Geomembranes for pipes?
June 1st, 2014
From the GMA Techline I have been asked to wrap a proposed 30-in. circular/cylindrical sanitary sewer pipe (HDPE) with a geomembrane as a dual containment layer. Could I get some pointers as to what kind of geomembrane(material, thickness, etc.) can be used to achieve this task? Any other information, such as pros and cons, would […]
HDPE liner panel orientation?
June 1st, 2014
From the GMA Techline I am reviewing a construction report where a landfill cell has HDPE one-sided texture laid about 45 degrees from the direction of steepest slope across approximately one-third of the sideslopes. I am looking for quantitative data on any testing done with this type of orientation or any opinions you may have […]
Geogrid reinforcing behind rigid concrete retaining walls
June 1st, 2014
From the GMA Techline I participated in the Bologna Symposium and I [was] very happy and honored to see you live. I read a [GMA Techline] answer published in Geosynthetics magazine (Oct./Nov. 2009, p. 58), “Geogrid use behind rigid concrete retaining walls.” You refer to the Japanese railroad system guideline to verify a more in-depth […]
Steep geosynthetic-reinforced slopes stabilize access routes for construction of 27-km tunnel
June 1st, 2014
Semmering Base Tunnel project in Austria By Sören Schmidt Introduction Following two years of preparatory work, main construction began on Austria’s 27-km Semmering Base Tunnel in January 2014. The tunnel between Mürzzuschlag and Gloggnitz on the Vienna–Villach/Graz main line is divided into three contract sections. The 13km central section is currently under construction, and two […]
FS for anchor trench calculations?
June 1st, 2014
From the GMA Techline Do you have a recommendation for what Factor of Safety to apply to the allowable geomembrane force for anchor trench calculations? (Melanie | Colorado) Reply: Over the years my thoughts have changed from having a high FS for geomembranes in their anchor trenches to treating the situation very differently. The motivation […]
GM19, Revision 7—Peel separation 5 out of 5?
June 1st, 2014
From the GMA Techline I am looking for a discussion of how peel separation % in the latest revision of GM19 went from 4 out of 5 specimens to 5 out of 5 specimens having to pass the 25% or less requirement. (Gabriel | California) Reply: Others have noticed it as well and in response […]
Minimum low temperature for dual hot-wedge seaming
June 1st, 2014
From the GMA Techline Does the Geosynthetic Research Institute (GRI) offer any guidance on the minimum allowable ambient temperature to perform double-track fusion welds of HDPE and LLDPE geomembranes? (Jonathan | South Carolina) Reply: We have GRI-GM9 Standard Practice “Cold Weather Seaming of Geomembranes” and it allows for seaming down to -15 C (5 F). […]
Seepage through geosynthetic-tube dam
June 1st, 2014
From the GMA Techline I am trying to determine the steady-state seepage through a stack of sand-filled geosynthetic tubes with a triangular cross section (4-3-2-1 tubes). The permeabilities of the sand and the tube material are known. Can you suggest places I should look to get information on how to analyze this problem? (Ray | […]
Use of geogrids in piggyback landfills
June 1st, 2014
From the GMA Techline Do you have any specific project information on the use of geogrids in constructing piggyback landfills, especially in cold climates? I am interested in examples of the use and evaluation of geogrids when building landfills over closed landfills. Any information you can provide as to landfill sites would be greatly appreciated. […]