Geomembrane Response in the Wide Strip Tension Test

The geomembrane wide strip tension test is a performance test that provides test data from which the stress-strain response of a geomembrane may be calculated. However, the volumetric response of the geomembrane must be accounted for when processing the test data to obtain the geomembrane stress-strain properties. This paper presents the results of strain controlled, uniaxial tension tests performed on two common polymeric geomembranes. During the tests, measurements were taken at specific locations on the geomembrane specimen. These measurements, combined with results from photographic analyses, allowed the specimen width and thickness to be determined during the tests. The measured values corresponded well with the theoretical values, assuming that the geomembrane is incompressible. The test results were not sensitive to the aspect ratio of the test specimen. The wide strip tension test should be considered a uniaxial (not a plane strain) tension test. It was also shown that modeling the stress-strain response of polymeric geomembranes with a constant cross sectional area instead of a constant volume significantly underestimates the actual stress-strain response of the geomembrane, particularly at large strains.