Research Associate, Louisiana Transportation Research Center, Louisiana State Univ., Baton Rouge, LA
Lab Manager, SGI Testing Services, LLC, Norcross, GA
Pages: 10 Published: Jul 2013
The internal shear strength of geosynthetic clay liners (GCLs) can be evaluated through direct shear testing in accordance with ASTM D6243 under a specific set of boundary conditions for a given normal stress. In order to prevent slippage at the GCL–gripping system interface and ensure an internal shear failure of the GCL, a gripping surface made of spikes 1 to 2mm tall mounted on a rigid substrate is recommended in the standard method and has been commonly used. It is recognized that certain boundary effects exist as a result of the aggressive gripping system. To improve the hydraulic performance and/or protect the bentonite core, a multi-component GCL is designed to have a thin membrane or film laminated or glued to one of the carrier geotextiles. It is necessary to investigate the boundary effect on the multi-component GCL internal shear strength tests, because the film– or membrane–geotextile interface is more prone to interference from the rough gripping surface recommended by the current standard. A series of internal shear strength tests were conducted on the same multi-component GCL product under different gripping conditions. It was found that tests using the aggressive gripping system yield a significantly higher peak shear strength of the multi-component GCL and a lower residual shear strength at large displacements.
multi-component GCL, shear strength, stability, direct shear, gripping surface, boundary effect
Paper ID: STP156220120075