JOURNAL ARTICLES

Pennsylvania’s Department of Environmental Protection (DEP) and Department of Community and Economic Development (DCED) officials have welcomed the recent emersion of companies that collect and reprocess geomembranes used in various aspects of Marcellus Shale oil and gas drilling, development, and production. The geomembrane uses include well pad liners, above ground impoundments, secondary containment, and floating covers. Well pad liners are placed over a large area (usually 200ft × 200ft) around the drill well to contain drilling fluids, provide an antislip surface for drill workers, and contain oil and gas products.

During the summer of 2007, the city of Franklin, Tennessee and its surroundings were experiencing a severe drought. Due to the high heat and low flows in the Harpeth River, Franklin struggled to meet water supply demands in the area. The city’s raw water reservoir, which can hold 85 million gallons, was completely dry for several months. As a result, the 2.0 MGD Franklin water treatment plant was inoperable for periods of time. Water is normally pumped from the Harpeth River into the raw water reservoir, where it is later treated before consumption.

For more than a decade, thermal welding has proven to be an efficient and costeffective procedure for field-seaming geomembranes. Thermal welding of polyvinyl chloride (PVC) geomembranes has allowed use of air-channel tests in lieu of destructive peel tests to verify field seams meet specified seam peel strength (Thomas and Stark, 2003).

This paper presents a comparison of single- and multi-interface strength tests for two possible landfill liner system configurations.

Some geomembranes are flexible enough that they can be factory seamed into large panels, folded, transported, unfolded without creasing or damage, and field seamed and tested as necessary. These geomembranes are relatively thin, flexible, and are mainly produced by calendaring, lamination, and extrusion manufacturing processes. In short, calendaring uses a series of hard pressure rollers to form a thin sheet of plastic material, e.g., a geomembrane. Lamination involves constructing a geomembrane by uniting two or more layers of material, e.g., two plastic sheets with a fabric or scrim in the middle. Extrusion manufacturing is a process used to create a thin plastic sheet by forcing heated plastic through a die of the desired thickness.

The objective of this paper is to present a procedure for high sheet temperature air channel testing of dual-track thermal seams for 0.75 mm thick polyvinyl chloride (PVC) geomembranes. The proposed relationship and equation allow the seam peel strength to be verified by field air channel testing without conducting destructive tests.