Contribution to the Long-Term Shear Strength of a Needle Punched GCL

Abstract

For the evaluation of the long-term internal shear strength of a needle punched geosynthetic clay liner, long-term shear creep rupture tests have been carried out. The tests were carried out at elevated temperature of 80 °C in de-ionized water with the purpose to accelerate the creep of the fibres so that faster failure times are forced. A normal stress of 50 kPa was applied while the shear stress was varied for each test. The test results showed that the time to shear failure directly depend on the applied shear stress and the shear stresses showed a clear correlation with failure times. The long-term internal shear stress has been determined through an extrapolation of the regression line at the test temperature of 80 °C. In addition to lifetime prediction, the applicable shear stress was calculated for a minimum of 100 years under a normal stress of 50 kPa at a given field temperature of 30 °C.