Archives

Soliciting all interested parties in creating a new geomat specification

April 1st, 2024

FIGURE 1 Polypropylene geomat with geotextile The Geosynthetic Institute (GSI) has a long history of creating industry-wide generic specifications for geosynthetics. At present, we have 23 promulgated and three others under development. Like all engineered materials, geosynthetics need general requirements/thresholds to incorporate into plans and specifications.  GSI is currently undertaking a new effort in regards […]

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Connection strength of geosynthetics anchored in concrete

February 1st, 2023

FIGURE 1 Photographs of various styles of embedment liners Nearly all geomembrane installations are fixed at the perimeter of the containment by burying the liner in an anchor trench or by attaching it to concrete (i.e., a collar wall, foundation, ring wall, manhole, vault, etc.). The standard approach for connecting the geomembrane liner to concrete […]

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Geomembranes with better performance

February 1st, 2023

Q:We are researching liner alternatives for an industrial client that will have lined impoundments subject to high temperature influent (>140 degrees F), low pH (1 SU+/-), and may have organic contaminants. Are there any polyethylene geomembranes that meet these requirements?  A: Thank you for your question about geomembranes with better performance than GRI GM13 GMB […]

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Strength Reduction Of Geogrids Used In Reinforced Walls

February 1st, 2023

Q:At the moment there are two issues that create uncertainty with the use of PET fabrics and geogrids in the Netherlands. First, for many years we built pile-supported geosynthetic reinforced embankments (so-called piled mattresses to reduce settlements under embankments on soft soils). The fill is supported by a geosynthetic mat, which rests on top of […]

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Transitioning from 30 MIL PVC geomembrane to 60 MIL HDPE

February 1st, 2023

Q:I have a client that operates a Subtitle C landfill that utilizes a double-liner system of 30 mil (0.76mm) PVC geomembrane for the base liner. They are wanting to evaluate the possibility to transition from 30 mil (0.76 mm) PVC to 60 mil (1.52 mm) high-density polyethylene (HDPE) geomembrane for the base liner system. In […]

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Overlap seam specifications for geotextile separators

February 1st, 2023

Q:What is the typical overlap for a geotextile used as a separator in a highway project?  A: This is a very simple question requiring an involved answer. Overlap seam specifications for geotextile separators are all over the place depending on material type and application. It is best to check the plans and specification, consult the […]

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Landfill Gas Emissions Modeling

February 1st, 2023

Q: I’m writing to see if you are aware of any research on landfill gas (LFG) emissions modeling through various geomembranes, particularly for temporary covers?  A: Landfill gas modeling is the practice of forecasting gas generation and recovery based on past and future waste disposal histories and estimates of collection system efficiency. It is an […]

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Do you have experience with T seams?

August 1st, 2022

Q: I have a question about T-intersections where three panels of geomembrane meet. In my experience these intersections have all needed to be repaired with a patch. However, a recent project fusion welded straight through these intersections. Air channel testing was completed on the first seam prior to completion of the perpendicular seam. After the […]

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Geosynthetic clay liner with aquiclude

August 1st, 2022

Q: We are trying to design and construct an aquiclude with a geosynthetic clay liner (GCL). Do you have any experience with this application where a GCL has been used as the impervious barrier between a flowing stream and the underlain geologic formation? A: I have not heard of a GCL being used alone in […]

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Working on an ethylene interpolymer alloy (EIA) specification

August 1st, 2022

Q: I have an upcoming project that will use ethylene interpolymer alloy (EIA). Is the Geosynthetic Research Institute (GRI) working on a specification for this material? A: Nice to hear from you and thanks for your Techline question. We have been working on this subject for a long time. GRI-draft GM34 standard specification revision 4 […]

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