Investigation of the local strains in a geosynthetic composite

Effects of the sample treatment and the strain gauge attachment on the local strains developed in a geosynthetic composite which is composed of a core layer of knitted textile needle-punched with two layers of nonwoven geotextile were investigated using a wide-width tensile test apparatus and a photogrammetric technique. It was found that to impregnate both ends of the specimen with epoxy to form stiff areas for claimping was an effective way of preventing slippage of the core knitted textile in the jaws so that uniform deformation of the test specimen could be obtained. It was also found that penetrating strain gauge cement into the geosynthetic composite to create two stiff bases on the geotextile for fixing both ends of the strain gauge provided an efficient manner for monitoring the tensile strain of the geotectile. The tensile strain readings obtained using the suggested installation method was comparable with those measured using the photogrammetric method.