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A landfill liner, or composite liner, is intended to be a low a permeable barrier, which is laid down under engineered landfill sites. Until it deteriorates, the liner retards migration of leachate, and its toxic constituents, into underlying aquifers or nearby rivers, causing spoliation of the local water. Modern landfills generally require a layer of compacted clay with a minimum required thickness and a maximum allowable hydraulic conductivity, overlaid by a high-density polyethylene geomembrane. The United States Environmental Protection Agency has stated that the barriers "will ultimately fail," while the site remains a threat for "thousands of years," suggesting that modern landfill designs delay but do not prevent ground and surface water pollution.〔(gfredlee.com ) - National Research Council of the National Academies (2007): ''Assessment of the Performance of Engineered Waste Containment Barriers''. Committee to Assess the Performance of Engineered Barriers. Washington DC.〕 Chipped or waste tires are used to support and insulate the liner.〔Benson, C. H., Olson, M. A. & Bergstrom, W. R. (1996) (Temperatures of Insulated Landfill Liner ), p24-31〕 == Mechanical Properties == The primary forms of mechanical degradation associated with geomembranes result from insufficient tensile strength, tear resistance, impact resistance, puncture resistance, and susceptibility to environmental stress cracking (ESC). The ideal method of assessing the amount of liner degradation would be by examining field samples over their service life. Due to the lengths of time required for field sampling tests, various laboratory-accelerated ageing tests have been developed to measure the important mechanical properties.〔Rowe, R. Kerry, S Rimal, and S Rimal. 2008. Aging of HDPE Geomembrane in Three Composite Landfill Liner Configurations. Journal of Geotechnical & Geoenvironmental Engineering. 134, no. 7: 906-916.〕 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「landfill liner」の詳細全文を読む スポンサード リンク
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