Creep testing and data extrapolation of reinforced GCLs

Abstract

Presented herein are the results of creep tests on three internally reinforced geosynthetic clay liners (GCLs) conducted for 1000 h at each increment of loading. Two of the GCLs were reinforced by needle punched and one was by stitch bonding. All three GCLs sustained loads up to 60% of their short-term strengths without any evidence of fiber pullout or breakage. The recorded deformations were nil at 20% loadings and were small, but measurable, at the higher loadings. Having the experimental data, the Kelvin–Chain model was used for extrapolation out to 1.0×10 6 h (114 years) from which isochronous time curves were plotted. The 100-year predicted deformation data at a 30% stress level is approximately 5 and 10 mm for the two needle punched GCLs, and approximately 10 mm for the stitch bonded GCL. It is concluded that such deformations are reasonable and can be accommodated by the reinforced GCLs currently being produced. There is a need, however, for additional investigation and to formalize a GCL specification to ensure that the proper polymer formulation is used in these materials.