Mechanical properties of two-layered specimens using homogenization approach

The triaxial compression test is widely used in the research for understanding mechanisms of soil properties and in engineering practice to characterize the strength and stiffness parameters. Layered soils are not often investigated due to the complexity in measured and evaluating strains. In unpaved structures, geogrids are normally used between compacted aggregate layer and weak soil layer. There is a need to understand the main mechanical properties at the soil-geogrid interface. Triaxial compression tests were carried out on homogeneous and two-layered specimens (unreinforced and reinforced) under a low effective confining pressure of 30 kPa. A new elastic homogenization approach was proposed to compare the stress-strain relationship of the layered soils with the homogeneous specimens. The main mechanical geotechnical properties of two-layered specimens were studied in terms of stress-strain and volumetric-strain curves. The homogenization method of specimens can give insight into the stiffness gain with the addition of geosynthetics at the interface.