CCR landfill final cover test pad—Part 1

August 1, 2020

By Nina J. Balsamo, John Massey-Norton, John R. Klamut, Terry Queen,Charles F. Straley and Mark R. Lehner An integrated drainage system (IDS) geomembrane, which provides both a low-permeability membrane and drainage space above the geomembrane, is being used in the final cover at a coal combustion residuals (CCR) landfill in West Virginia. Part 1 of …

Innovative geosynthetic solution saves 106-year-old Panama Canal structures

By Tom Stephens and Nicolas Ruiz The Panama Canal opened for business 106 years ago and was hailed as the eighth wonder of the world and an engineering marvel. It has become the most consequential global waterway ever constructed. Since 1914, more than a million ships of all sizes have passed through the canal’s original …

PVC sheet piling for cutoff and containment barriers

By Brendan Sheppard and Steve Hargrave Polyvinyl chloride (PVC) sheet piling (Figure 1) has been used for more than 25 years in bulkheads throughout the United States and beyond as a replacement for steel, concrete and timber materials due to the high corrosion resistance it offers in marine environments. More recently, barrier walls have been …

The GMA Techline

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 …

EPA finalizes revisions to the coal ash closure regulations, increases public access to information

July 30, 2020

On July 29, the U.S. Environmental Protection Agency (EPA) finalized several changes to the regulations for coal combustion residuals, known as CCR or coal ash, to implement the court’s vacatur of certain closure requirements as well as adding provisions that enhance the public’s access to information about the management of coal ash at electric utilities. …

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Enhanced moisture management of pavement systems through capillary suction

June 1, 2020

By René B. Laprade and John M. Lostumbo Moisture within pavement layers is a principal cause of pavement deterioration (Cedergren 1994, Christopher and McGuffey 1997, Henry and Holtz 2001). Specific problems associated with moisture include (1) reduction in pavement strength caused by excess water in the base course layers and/or the subgrade soils, (2) shrinking …

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Assessment of condition of an uncovered geosynthetic landfill bottom liner system

By James L. Hanson and Nazlı Yeşiller Composite liner systems consisting of geomembranes (GMs) placed over geosynthetic clay liners (GCLs) commonly are used for containment applications. Such systems are used in base liners for ponds, reservoirs, basins and canals, and bottom and cover liner systems for landfill facilities. Even though the use of GCL-GM composites …

The GMA Techline

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 …

High-strength geocell and geogrid hybrid reinforcement

Compressor station gravel pad on soft subgrade By Sanat Pokharel, Timothy Yii, Marc Breault and Meisam Norouzi Infrastructure development in natural resources rich Alberta, Canada, often encounters very soft ground conditions that pose several construction and sustainability challenges to transportation infrastructure, such as roads, rails and pipelines. As the conventional construction practices may not always …

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Geosynthetic strip MSE wall at Point Defiance Marina

April 1, 2020

By Paul C. Frankenberger and Robert Lozano  This article will focus on a geosynthetic strip mechanically stabilized earth (MSE) wall case study using discrete geosynthetic strips with large precast facing panels (Figure 1), an innovation of the original MSE invention. The system is the Highway Innovative Technology Evaluation Center/National Transportation Product Evaluation Program reviewed GeoMega …