Peaking Deflections of Flexible Pipe during Initial Backfilling Process

Abstract

Most thermoplastic pipes exhibit peaking behavior during the initial backfilling process. It is shown with the actual field data that the peaking deflections can be beneficial for minimizing the long-term deflections of the pipe. An approach similar to the one proposed by Spangler is used to derive a formula for estimating the peaking deflections of thermoplastic pipe due to forces generated during the initial backfilling. The formula is tested in light of a number of field installation cases. The results show that the proposed formula predicts peaking deflections of both polyvinyl chloride and high density polyethylene pipes accurately under a variety of backfilled conditions.