Geomembrane Monitoring Articles

  • Detection and Location of Leaks in Geomembrane Liners Using an Electrical Method: Case Histories

    ABSTRACT A field-proven electrical technique, developed at Southwest Research Institute, San Antonio, Texas, is commercially available to detect and locate leaks in geomembrane liners. The electrical technique is used to inspect 100% of the geomembrane material that is covered by a conducting liquid. A voltage applied across the liner produces a uniform electrical potential distribution in ...

  • Costs and Benefits of Geomembrane Liner Installation CQA

    ABSTRACT Because the cost of third-party construction quality assurance (CQA) of geomembrane liner installations is typically comparable to the cost of the geomembrane liner, CQA must be optimized to obtain the most benefit for the owner, rate payers, and environment. A regulation-based CQA protocol usually includes testing the material, observing the quality control (QC) program of the ...

  • Performance-Based Specification Of Electrical Leak Location Surveys For Geomembrane Liners

    ABSTRACT Electrical leak location surveys can be a crucial part of the final quality control of geomembrane liner installations. The method has been offered as a commercial service since 1985 and is the only practical test method that can find holes in the liner after protective soil cover is put on the liner. During the past fourteen years the test method has been used on a wide variety of ...

  • Experience with GCLs used as a conductive layer in geomembrane leak-location surveys

    Engineers, installers, regulators, and owners are starting to rely on geomembrane leak-location surveys as part of the construction quality assurance for landfills. The various methods are described in ASTM Standard D 6747.' Standard procedures for conducting leak-location surveys of geomembranes covered with earth materials are described in ASTM Standard D 7007.2 Figure 1 shows the ...

  • Enhanced Geomembrane CQA through proper application of geomembrane leak location surveys

    Abstract Historically, geomembrane construction quality assurance (CQA) has focused on destructive testing of welded seams to verify seam strength and integrity. Paradoxically, seams are not subject to significant stress and practically never fail in service, while holes and construction damage in the geomembrane are a much more widespread problem. The historical approach fails to evaluate ...

  • Cutting holes for testing vs. testing for holes

    When it comes to geomembrane quality assurance, are destructive testing practices as effective as basic leak detection technologies? The function of a geomembrane liner is to prevent liquid flow to the environment. CQA measures should be judged on how effective they are in meeting this requirement. This article critically examines the industry’s current means of providing confidence ...

  • Locating Geomembrane Liner Leaks under Waste in a Landfill

    Abstract An Electrical Leak Imaging and Monitoring (ELIM SM) survey was used to locate leaks under 2.5 meters of stabilized waste in an active geomembrane-Iined landfill. The landfill is lined with two 2-mm thick HDPE geomembranes that are separated by a geonet drainage layer. The primary liner is covered with 600 mm of drainage sand and 2.5 meters of stabilized waste for a total cover ...

  • Strain Measurement in HDPE Geomembrane Tensile Tests

    According to ASTM D 638, the tensile strain in an HDPE geomembrane dumbbell specimen subjected to a tensile test should be evaluated using an extensometer that records the elongation of a defined length of the central portion of the specimen. However, the current practice in the United States for HDPE geomembrane quality control and conformance testing consists of following the 1991 NSF standard ...


    By ASTM International

  • Notched Constant Tensile Load (NCTL) Test for High-Density Polyethylene Geomembranes

    A modification of an old test method, the notched constant tensile load (NCTL) test, is reintroduced to evaluate the stress-cracking performance of high-density polyethylene (HDPE) geomembranes. In this modified test, notched dumbbell-shaped specimens are subjected to a range of constant tensile loads in a 10% Igepal (CO-630) solution at 50°C. The method has been proposed to ASTM and is being ...


    By ASTM International

  • Axisymmetric Tension Testing of Geomembranes

    The newly developed axisymmetric tension test is useful in evaluating the performance of geomembranes subjected to out-of-plane stress conditions such as those that can develop due to localized subsidence under waste-containment cover and liner systems. In this paper, the equations necessary to describe the geomembrane stresses and strains during testing are derived, and equations used to ...


    By ASTM International

  • Time-Temperature Superposition in Mechanical Durability Testing of Polyethylene Geomembranes

    The mechanical durability of polyethylene geomembranes is considered in this technical note. Polyethylene plastic pipe research has shown that there are universal factors for shifting high-temperature failure (short time) data to low temperatures (long time). Data presented here indicate that these same shift factors may also apply to geomembranes. Crack growth rate studies are proposed as a ...


    By ASTM International

  • CBR Strength (Puncture) of Geosynthetics

    While there exist many types of mechanical tests for use on geosynthetics, most seem to be more suitable for one type of system or another. This paper focuses on a test which may have widespread applicability to assess the strength of all types of geosynthetics. It is the forcing of a 50-mm (2.0-in.) diameter plunger through a horizontally fixed geosynthetic of 150-mm (6.0-in.) diameter. Such ...


    By ASTM International

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