Design of a CCR composite liner system

August 1, 2021  |  Q&A: GMA Techline

Q: We are designing a composite liner system for a coal ash landfill. From the bottom-up, the cross section is subgrade soil, geosynthetic clay liner (GCL), geomembrane, composite drainage layer with nonwoven geotextiles on both sides and then ash from coal combustion residuals (CCR). Do you have an…
Read More
A geotextile filter for an edge drain

August 1, 2021  |  Q&A: GMA Techline

Q: I am doing a geotextile filter design for a highway edge drain. All I have from the site is a grain size analysis of the sandy subgrade soil. Can you point me in the right direction?
Read More
Bluff repair in seismically active zone

August 1, 2021  |  Q&A: GMA Techline

Q: I am doing a bluff repair on the West Coast in a seismically active zone. Can you direct me to where I can get some design guidance?
Read More
Service life of nonwovens

August 1, 2021  |  Q&A: GMA Techline

Q: Where can I find literature on the useful service life of nonwoven geosynthetic fabrics installed in soils?
Read More
Metal leaching from geosynthetics

August 1, 2021  |  Q&A: GMA Techline

Q: Geosynthetics are made from polymers that use metal-based catalysts in their formulations. Do geosynthetics have the potential to leach metals into the environment?
Read More
Bringing geomembranes into equilibrium with atmosphere

August 1, 2021  |  Q&A: GMA Techline

Q: Some ASTM test methods request that one brings the specimens into equilibrium with the atmosphere prior to the test (some of them determine the conditions: 21±2ºC and 60±10% relative humidity). Considering that we just produce polyethylene geomembranes, and they are not significantly affected …
Read More
OIT for UV and oven aging

June 1, 2021  |  Q&A: GMA Techline

Q: I am contacting you in regard to the requirements for oxidative induction time (OIT) (standard [STD] and high pressure [HP]) in the GRI-GM13 specification for both ultraviolet light and oven aging. Do you need to conduct both OIT tests or just one or the other?
Read More
Geotextile under articulated systems in slope armoring

June 1, 2021  |  Q&A: GMA Techline

Q: I have a question about the geotextile placed under articulated systems in slope armoring. Based on my understanding, a drainage layer is recommended between the geotextile and the armoring structure, but, since the armoring structure has some spaces in between the armoring blocks, won’t the pa…
Read More
Industry standard for wall drainage systems?

June 1, 2021  |  Q&A: GMA Techline

Q: I just watched your recorded video of mechanically stabilized earth (MSE) wall inspection. Thank you for the presentation; it was very informative. I do have a follow-up question for you. I was recently the site engineer for a precast panel MSE wall and now have the opportunity to inspect constru…
Read More
GCLs in cold temperatures

June 1, 2021  |  Q&A: GMA Techline

Q: I am working on supporting a guide (independent) on what to consider when geosynthetic clay liners (GCLs) are installed in minus temperature regions (e.g., –4˚F [–20˚C]). There is not much published on this, especially independently.
Read More