Progressive Damage to GCLs Under Repeated Load Cycles: Fid-Bau Portal

Progressive Damage to GCLs Under Repeated Load Cycles

Pillai, Anjali G. / Latha, Gali Madhavi

Geosynthetic clay liner is used in the design of cover and barrier systems in engineered landfills. The shear strength at the interfaces is critical for slope stability. Though the interface shear characteristics of natural sand with GCLs are well established in literature, the recent problems of sand extraction and its harmful impact on coastal erosion has rendered it impractical. The geotechnical application of manufactured sand (Msand) is an uncharted field even though it has been approved as an admissible alternative to natural sand for manufacturing of concrete. The study involves analyzing the interface shear strength of GCLs with manufactured sand and compare them against river sand for identical loading conditions and identical gradations. The initial phase of study subjected the non-woven interface of GCL to interface shear tests with sands. To simulate the field conditions and to give an insight into the reduction of shear strength, same GCL specimen is subjected to repeated cycles of loading. Results showed continuous reduction in displacement values at which peak shear stress was attained. The interface shear strength parameters are evaluated for both interfaces. The assessment of surface changes of GCL due to the interaction with different type of sand is digital image analysis using MATLAB. The damage to the specimen is quantified on the reduction of shear strength over the cycles. Results from these studies provide conclusive indication to replace natural sand with Msand in landfills in terms of interface shear characteristics.