Call For Papers: TRB Annual Meeting

June 1, 2009

The 89th sessions of the Transportation Research Board will be held Jan. 10-14, 2010, in Washington, D.C. Call Title: Innovations in Geosynthetic Drainage Technologies; Sponsoring Committee: AFS60 – Subsurface Drainage; Co-Sponsoring Committee(s): AFS70 – Geosynthetics; Call organizer: Dr. John C. Stormont (jcstorm@unm.edu”). This session solicits papers dealing with innovative applications of geosynthetics to provide drainage …

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Fixing an exposed landfill cover

By Timothy D. Stark Q: The following photo shows a landfill cover with a gray material exposed. Is this good? If not, what should be done? A: A close-up of the gray material indicates that it is the geomembrane that is part of the final cover system for this landfill. This is not good and …

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Design strength for GCLs

By Timothy D. Stark Q: What design strength should be used for GCLs? A: If the GCL is not encapsulated between two geomembranes, the slope design should/must assume that the GCL will be fully hydrated at a low normal stress (e.g., 5–10 psi for a liner system). If the GCL will be encapsulated between two …

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Maximum slope angle for geosynthetic-lined slopes

By Timothy D. Stark Q: Is there a maximum slope angle for geosynthetic-lined slopes? A: Yes there is, and the slope angle should not exceed the lowest geosynthetic interface friction angle, δ, of the system. The slope angle should not exceed δ because this condition can/will lead to tension developing in the geosynthetics and possibly …

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The effects of heat on Subtitle D composite liner systems

By Timothy D. Stark Q: What effect does heat have on a Subtitle D composite liner system? A: Heat can have many detrimental effects on a Subtitle D composite liner system. For example, heat can adversely affect the compacted low permeability soil liner by reducing its moisture content, leading to an increase in hydraulic conductivity …

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GCLs and hydraulic equivalence

By Timothy D. Stark Q: Are GCLs hydraulically equivalent to a compacted low permeability soil liner? A: A good, but difficult, question. GCLs are hydraulically equivalent to low permeability soil liner in terms of advective flow. However, GCLs are not hydraulically equivalent to low permeability soil liner in terms of diffusive flow unless a natural …

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The difference between strength parameters

By Timothy D. Stark Q: What is the difference between the strength parameters c and ø, and a and δ? A: Good question because these parameters are frequently used interchangeably. c and ø, and a and δ are shear strength parameters used to represent the strength/failure envelope for a particular material. The strength envelope is …

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Geotextiles in levees (Part 2 of 2)

History, performance, and design of geotextiles in levees: A report from New Orleans By Jody Dendurent and Mark Woodward Editor’s note: Part 1 of this 2-part series ran in the April/May issue of Geosynthetics. Following the Abstract and Introduction below, Part 2 concludes with sections 3, 4, and 5 of this manuscript. Abstract Geotextiles are …

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Geosynthetics revive Irish bog

Geosynthetics-lined ‘floating trail’ protects and displays rejuvenated blanket bog at Cuilcagh By Shelby Gonzalez Introduction: Bringing a bog back to life In the late 1980s, the blanket bog on the slopes of Cuilcagh Mountain in County Fermanagh, Northern Ireland, was in bad shape. Years of overgrazing, mechanized peat harvesting, and other mistreatment had damaged the …

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Geosynthetics at Flurry Bog

Piled embankment design, construction,and monitoring for A1/N1 dual-roadway By Wyatt Orsmond Introduction The A1/N1 section of highway between Newry and Dundalk forms part of a strategic transportation link between Belfast and Dublin. This section includes 14.5km (9mi.) of high-quality, dual-carriageway (divided-highway) construction and was challenged by a tight route corridor threaded between steep mountains and …