INTERACTION BEHAVIOR OF STEEL GRID REINFORCEMENTS IN A CLAYEY SAND

The interaction behaviour between steel grid reinforcements and a clay ey sand has been studied in laboratory and field pullout tests. The cl ayey sand is potentially useful as cheap, low quality, locally availab le and cohesive-frictional backfill in the construction of mechanicall y stabilized earth walls and embankments, especially in coastal areas. The laboratory tests were conducted under undrained conditions at thr ee compaction moisture conditions. The field tests were conducted on d ummy reinforcements embedded at different elevations in a full-scale t est embankment resting on soft clay foundation. The laboratory tests r evealed that the moisture content of the compacted soil, compaction st ress, applied normal stress level, diameter and spacing to diameter ra tios of the transverse members of the steel grid, all affect the soil- reinforcement interaction, and thereby, also the magnitudes of the pul lout resistances. Interferences between the bearing transverse members of the grid were found to be less significant for spacing to diameter ratios above 75. The laboratory tests, in general, gave conservative values of the pullout resistances as compared with the field tests. Th e proposed prediction equations agreed well with the experimental data .