No dilatancy is observed in the sand mass during the interface
shear tests, even though the sand specimens are dense.
This behavior confirms that the stress induced during shearing
is not large enough to disturb the whole sand specimen because
the FRP surface is relatively smooth. Under these conditions,
sliding dominates the shear resistance (O’Rouke et al.
1990; Dove 1996). If the roughness of the interface is increased,
dilatancy of the sand would be expected to occur, just
as Lehane et al. (1993) and Paikowsky et al. (1995) observed