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The GMA Techline
August 1st, 2020
Seaming dissimilar geomembranes Q: I kindly request your technical support in the questions below: A nonpolyethylene geomembrane was used in phase 1 of the tailings dam waterproofing system of a gold mine. For the expansion (phase 2), the use of a high-density polyethylene (HDPE) geomembrane is being evaluated. How can the HDPE geomembrane join the bituminous […]
The GMA Techline
June 1st, 2020
Moderated by George R. Koerner Minimum sediment thickness Q: We are going to construct some evaporation ponds on existing sediment on top of a Hypalon geomembrane. The sediment looks to be predominantly fine. The subgrade condition below the liner is not known for sure. In such conditions, can you recommend a minimum sediment thickness that […]
Test method for determining leakage through imperfections in GMs of a composite liner system
June 1st, 2020
George R. Koerner This article describes a large-scale test method intended to determine the leakage through imperfections in a geomembrane (GM) under a given head. It can be used as a performance test to simulate field conditions where the GM is physically breached. The test method places a GM test specimen of 2 feet (0.6 […]
How does your geosynthetic react to changes in temperature?
April 1st, 2020
An essential aspect of geosynthetics is that they function well over a large range of temperatures in either buried or exposed environments. There has been much work in this area; see Giroud and Morel (1992), Koerner and Koerner (1995 and 2006), Lord, Soong and Koerner (1995), and Tsuboi, Imaizumi and Miyaji (1998). Most of the […]
The GMA Techline
April 1st, 2020
Moderated by George R. Koerner and Y. “Grace” Hsuan Welding Rod Q: This question is in regard to the welding rod intended for welding of geomembranes (both high-density polyethylene [HDPE] and linear low-density polyethylene [LLDPE]). Are there any GRI GM13- or GM17-based requirements for welding rods or are there any white papers or specifications? I […]
The GMA Techline
August 1st, 2019
Moderated by Robert M. Koerner, George R. Koerner and Y. “Grace” Hsuan A geotextile for unpaved driveway/road? Q: Is there any point in using a 150 g/m2 (4.4 oz/yd2) nonwoven geotextile in building an unpaved gravel driveway or gravel road? If so, what should be the most important characteristics of the fabric and what are […]
Commentary on flood abatement using geosynthetics
August 1st, 2019
By Robert M. and George R. Koerner Figure 1a: Geosynthetic reinforced steep soil slopes (courtesy W. Hsieh On Sept. 8, 1900, a Category 4 hurricane struck Galveston, Texas, which is situated on the Gulf of Mexico about 8 feet (2.4 m) above sea level. The storm created a 15-foot (4.6-m) storm surge, killing 8,000 to […]
The GMA Techline
June 1st, 2019
Who is doing the testing? Q: This question relates to the number of rolls to be selected as the lot sample for specification conformance testing and refers to ASTM D4354. When I look at this standard, it appears the values in Table 1 of GRI’s White Paper #10 refer to the number of units to […]
Reflections on sustainability with respect to geosynthetic materials
June 1st, 2019
By Robert M. and George R. Koerner Listening to and reading the news, there seems to be regular criticism of all plastics insofar as concerns as to their post-use disposal in light of their exceedingly long lifetimes. Rarely, if ever, is the distinction made as to which plastics are really necessary to society and which […]
MSE wall failures can be mitigated through the use of geotextile filters
April 1st, 2019
For the past 17 years, the Geosynthetic Institute (GSI) has been accumulating data on failures of geosynthetic reinforced mechanically stabilized earth (MSE) retaining walls. We presently have 320 cases, of which 201 (63%) have been caused in whole or part by water within, or adjacent to, the reinforced soil zone. We sincerely hope that our […]