Behavior of a Soil-Tire Shreds Backfill for Modular Block-Wall

In this study, soil-tire shreds was used as a backfill material behind a fully instrumented modular wall. A mechanically stabilized earth wall reinforced with geotextiles and geogrids and backfilled with a sand-tire shred mixture (25% tire shreds by volume) was designed and constructed using conventional geotechnical methods. After construction, the wall was loaded with a surcharge and monitored to assess the mass behavior of soil-tire shred backfills. Successive surcharges were placed corresponding to 42, 95, 148, and 200 kPa. The wall was instrumented with earth pressure cells, position transducers to measure displacement of the wall face, and strain gages to monitor strains in the geosynthetic reinforcement. Horizontal and vertical pressures behind the wall increased as the surcharge was placed, but at different rates depending on depth. Strain in the geotextile and geogrid layers also increased as the surcharge increased, with larger strains occurring near the face of the wall. Displacements of the face of the wall were largest near the top, and increased as the surcharge was placed. However, the displacements generally were small, even under the heavy surcharge. A favorable comparison was also obtained between deformations predicted using a finite element model and those measured in the field. The small displacements that were observed demonstrated that earth structures using soil-tire shreds backfills can be reliably designed and constructed with conventional geotechnical methods.