Shear behavior of geocell-geofoam composite

Abstract

In design, internal stability of EPS lightweight fills are provided either by applying load distributing mechanisms (thick pavements or concrete slabs) or using more strong lightweight material through denser EPS geofoam blocks. However, unit weight of the EPS geofoam is a limited parameter. As an attempt to improve the mechanical properties of EPS geofoam, geocell-geofoam composite (GGC) is introduced in this study. Geocell mattresses were infilled with solidified geofoam beads in the factory to fabricate GGC. The EPS geofoam and GGC samples were tested using a large-scale shear test apparatus of size measuring 1 m3. Results indicate that inclusion of the geocell leads to a considerable increase in the shear strength and a great decline in the compressibility of the geofoam. In comparison with EPS blocks, up to 72% rise in the shear strength and 67% decline in the vertical displacement were observed in GGC samples at the normal stress of 35 kPa. In addition, incorporation of the geocell was found to change the resisting mechanism of the EPS geofoam from cohesive to cohesive-frictional. While there was only 4.5% decline in the cohesion, the internal friction angle of the tested geofoam increased six-fold due to the involvement of the geocell.