GCLs in cold temperatures

June 1st, 2021

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. This is the only thing I found: Designation: D6102-20Standard Guide for Installation of Geosynthetic Clay Liners5.3.8 The GCL should […]

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Useful service life of nonwoven geosynthetics

June 1st, 2021

Q: Where can I find literature on the useful service life of nonwoven geosynthetic fabrics installed in soils? Thank you. A: Nice to hear from you and thanks for your question in regard to the service life of nonwoven geotextiles.  Below is a reference that I think is very good. In addition, I have exhumed […]

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OIT for UV and oven aging

June 1st, 2021

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? A: I would strongly recommend reading the EuroGeo 4 […]

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Geotextile under articulated systems in slope armoring

June 1st, 2021

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 particles of the drainage layer be washed out through […]

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Industry standard for wall drainage systems?

June 1st, 2021

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 construction of the wall that […]

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Anchors, tie-rods and whalers

April 1st, 2021

Q: We are having issues related to obstructions in the reinforced zone of our mechanically stabilized earth (MSE) retaining walls. In the first case, there is a rock outcrop that is limiting the length of the geogrid reinforcement. In the second case, we have a drop-down inlet structure to divert stormwater, which is in the […]

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Geomembranes for reinforcement?

April 1st, 2021

Q: We are using Robert Koerner’s Designing with Geosynthetics to calculate the required thickness of a geomembrane. See Figure 1 and Equation 1 from the book for details. Figure 1 Equation 1 Can you point us in the right direction with the mobilization distance, x? A: Yes, please see Figure 2 for high-density polyethylene (HDPE). […]

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Installing a geomembrane low to high gradient?

April 1st, 2021

Q: We are a large liner installation firm that has been asked to install a geomembrane liner from low gradient to high gradient. Is this the new normal? A: This is not normal, and we suggest you strongly object to this recommendation. There are many stakeholders in regard to panel layout (i.e., installer, general contractor, […]

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GRI-GM19 peel specification

April 1st, 2021

Q: Our liner system is a double composite and along a western tie-in. We need to extrusion-weld the secondary 60-mil (1.5-mm) HDPE (new cell) to an existing secondary 40-mil (1-mm) HDPE (old cell), and the state is continuing to have issues with the fact that we are using the 40-mil (1-mm) GRI-GM19 peel specification as […]

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Concrete interlayers

April 1st, 2021

Q: We are interested in using a geotextile as an “unbonded concrete interlayer” over existing concrete pavement to float the new slab over deteriorated pavement, instead of a thin asphalt layer. Do you have any guidance for us in this regard? A: Over the past several years, 16-ounce-per-square-yard (542-g/m2) nonwoven needlepunched geotextiles have been used […]

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