Characterization of textured geomembranes predictive of interface properties

June 1st, 2009

Currently under development is a new application of technology for textured geomembrane sheet characterization. By Boyd Ramsey and Jimmy Youngblood Introduction Currently under development is a new application of technology for textured geomembrane sheet characterization. We believe this method of characterization will demonstrate a strong correlation to interface shear testing with a more rapid testing […]

Read More Edit

Geosynthetics at Flurry Bog

June 1st, 2009

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 […]

Read More Edit

Geosynthetics revive Irish bog

June 1st, 2009

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 […]

Read More Edit

Geotextiles in levees (Part 2 of 2)

June 1st, 2009

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 […]

Read More Edit

The difference between strength parameters

June 1st, 2009

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 […]

Read More Edit

GCLs and hydraulic equivalence

June 1st, 2009

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 […]

Read More Edit

The effects of heat on Subtitle D composite liner systems

June 1st, 2009

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 […]

Read More Edit

Maximum slope angle for geosynthetic-lined slopes

June 1st, 2009

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 […]

Read More Edit

Design strength for GCLs

June 1st, 2009

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 […]

Read More Edit

Fixing an exposed landfill cover

June 1st, 2009

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 […]

Read More Edit