INTERACTION BETWEEN REINFORCING GEOSYNTHETICS AND SOIL TIRE CHIP MIXTURES

The objective of the present study was to evaluate the mechanical prop erties of tire chips and soil-tire chip mixtures relevant to geosynthe tic-reinforced earthworks. Tests were conducted to evaluate shear stre ngth and pull-out capacity with a woven geotextile and two geogrids. S oil-tire chip mixtures made with clean sand and sandy silt were tested . These properties were then used to assess the potential advantages o f using soil-tire chip backfills for geosynthetic-reinforced retaining walls and embankments. The test results show that the geosynthetic pu ll-out force in tire chip and soil-tire chip backfills increases with displacement-i.e., no peak pull-out force is generally obtained, at le ast for displacements less than or equal to 100 mm. Pull-out interacti on coefficients for tire chip backfills are typically greater than 1, whereas for soil-tire chip backfills they typically range between 0.2 and 0.7, even though the pull-out capacity for soil-tire chip backfill s is generally similar to or greater than the pull-out capacity in a s oil backfill. The higher strength, lower unit weight and good backfill -geosynthetic interaction obtained with soil-tire chip backfills can r esult in walls requiring less geosynthetic reinforcement than walls ba ckfilled with soil. In addition, embankments can potentially be constr ucted with steeper slopes and a smaller volume of material when soil-t ire chip fill is used, while providing greater resistance against late ral sliding and foundation settlement.