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The Service Life of Geomembrane Liners: Actions to be Taken

Explore comprehensive actions for extending the service life of geomembrane liners, covering steps for regulators, owners, designers, manufacturers, and more. Learn key responsibilities and crucial aspects of geomembrane installation and maintenance.

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The Service Life of Geomembrane Liners: Actions to be Taken

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  1. The Service Life of Geomembrane Liners: Actions to be Taken Ian D. Peggs I-CORP INTERNATIONAL, Inc. Ocean Ridge, USA EuroGeo 3 Munich March 2004

  2. RESPONSIBILITIES REST WITH: • Regulator • Owner • Design engineer • Manufacturer • Fabricator/installer • CQA firm • Earthworks contractor • Operator

  3. REGULATOR: • Knowledgeable staff who do not: • only decide to do an electrical integrity survey at the end of construction • decide that a permitted 1 m of sand on a 3:1 slope is now inadequate and demand it be increased to 1.7 m – it all falls down! • require that HDPE be used for every liner application • expect a zero leakage rate through a single liner

  4. OWNER • Hire experienced design engineer • Hire independent CQA firm to report directly to owner or engineer • Hire adequate CQA staff • Do CQA as soils cover geosynthetics • Require liner integrity survey • Prepare operational plan for first layer of waste placed on liner

  5. MOBILE LEAK SURVEY: 600 mm STONES, 3 m WATER. DRAG PROBE USED. LEAK IN MIDDLE. BURN-THROUGH LOCATED WITHIN 5 mm

  6. 1 mm LEAK AT TIP OF PEN FOUND USING WATER LANCE SURVEY

  7. DESIGN ENGINEER • Do not practice outside expertise • Design for electrical integrity survey • Select correct material/grade • Specify material correctly • Hire experienced installer • Ensure manufacturer/installer can meet specifications • Ensure adequate CQA is performed – subgrade to cover soil • Require electrical integrity survey

  8. DESIGN ANOMALY • Geomembrane liners are designed with minimum stress…….. • ……. then we use double textured geomembrane to keep soil on slopes! • May be acceptable with LLDPE, PP, PVC but not HDPE…… • ……. unless HDPE has adequate SCR • Extra care in bioreactors with higher temperatures and more settlement on slopes

  9. MANUFACTURER/INSTALLER • Read and meet specifications • Do not assume anything • Be consistent with, and only improve, additives • Get to understand SIP • Generate fully integrated QA/QC documents • Deliver QA/QC documents with products

  10. WELD AIR WELD SIP IN HDPE GEOMEMBRANE SEAM

  11. CQA • Generate integrated CQA Plan • Use experienced staff • Use sufficient staff • Integrated records • Record failing data • Monitor cover soil placement

  12. FOUND BY FAST IRS SURVEY

  13. HDPE • SCR (ASTM D5397) • OIT (standard or high pressure) • Thermal aging (GRI.GM13, S-OIT) • UV resistance (GRI.GM13, HP-OIT) • Seam shear elongation • Seam peel separation • SIP • [Why is weld shear strength f(thickness)?]

  14. PP • Montell CA743GA, CA721GW, CA1722GW resins • Thermal Aging (GRI.GM18, HP-OIT) • UV Resistance (GRI.GM18, HP-OIT) • Note black vs non-black • Leaching out additives • Aging under stress • Seam shear elongation • Seam peel separation • SIP

  15. DELAMINATION IN 1 mm PP

  16. LLDPE • Density (0.935 g/cm3) • OIT (standard or high pressure) • Thermal aging (GRI.GM17) • UV resistance (GRI.GM17) • Seam shear elongation • Seam peel separation

  17. PVC • Plasticizer • To cover or not is f(plasticizer) • PVC alloys • 30 year experience • Seam shear elongation • Seam peel separation (allowed)

  18. PLASTICIZER RETENTION • Plasticizer permanence is a function of molecular weight. • PGI recently updated the PGI 1104 spec to include a minimum MW of 400.

  19. CONFINED GEOMEMBRANE MAXIMUM ALLOWABLE STRAIN • SMOOTH HDPE (SCR <1500 HR) 6% • SMOOTH HDPE (SCR >1500 HR) 8% • HDPE STRUCTURED SURFACE 6% • HDPE RANDOM TEXTURE 4% • LLDPE (DENSITY >0.935 g/cm3) 10% • LLDPE (DENSITY <0.935 g/cm3) 12% • STRUCTURED LLDPE 10% • TEXTURED LLDPE 8% • SMOOTH PP 15% • THIS ONLY APPLIES TO GEOMEMBRANE CONFINED BETWEEN TWO SOIL LAYERS. IT SHOULD NOT BE APPLIED TO UNCONFINED GEOMEMBRANE.

  20. FOR OPTIMUM DURABILITY: • Sensible regulation • Experienced engineer • Considered material/specifications • Good installation • Knowledgeable CQA • Appropriate conformance testing • Final integrity survey • Careful initial operations • 400 years covered, 75 years exposed?

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