H.B. Poorooshasb - Department of Building, Civil and Environmental Engineering Concordia University, Montreal, Canada

The latest version of the CANAsand constitutive model, Noorzad (1998), is used to evaluate the mode of deformation and change of the stress regime in a layered sand deposit resting on a pervious rigid bed. The output from this evaluation is used, in turn, to study the performance of a rigid (concrete) pile and a compacted gravel pile (also known, unfortunately, as a stone column). In the case of the concrete pile graphs representing the distribution of the shear force and bending moments along the pile are presented and discussed. For compacted gravel, particular attention is given to the effect of reduction of the lateral stress component on the integrity of the pile. Such a stress reduction can have a devastating effect on the stability of the unit. Since the gravel piles are always placed as a group and at a close pitch this effect is likely to be of greater importance to the piles (columns) installed at the perimeter of the group.