Granular backfill selection for direct embedded poles

The ultimate capacity and moment-displacement behavior of direct embedded transmission line pole foundations are dependent on the strength and deformation properties of the backfill material placed in the annulus surrounding the pole. This paper summarizes research conducted to measure: the strength and deformation properties of granular backfill materials; and their influence on direct embedded pole foundation behavior. The research found that compacted well-graded granular backfills had the greatest stiffness and strength. The degree of compaction has a greater influence on stiffness than strength.