Effect of backfill properties and surface treatment on the capacity of adfreeze pipe piles

• Published in: Canadian Geotechnical Journal
• Main Authors: Sego, D. C., Smith, L. B.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Canadian Science Publishing 1989
• Subjects: Ice; permafrost
• Online Access: http://dx.doi.org/10.1139/t89-082; http://www.nrcresearchpress.com/doi/pdf/10.1139/t89-082

This note presents the results of a limited number of laboratory-scale pile load tests to establish those modifications to current pile construction procedures that would be most effective in increasing pile capacity. The results indicate that the properties of the backfill (ice content, salinity, and size of annulus) have a significant influence on short-term pile capacity, while the properties of the native soil are less important. The results demonstrate that the pile capacity can be maximized through the use of nonsaline sand backfill. In saline soils, the shear strength at the backfill - native soil interface may govern the design, and must be evaluated together with the adfreeze strength at the pile-backfill interface. The results also demonstrate that the roughness of the outside surface of the pile has a significant influence on adfreeze strength. Sandblasting the pile surface doubled the adfreeze strength at the pipe-backfill interface. This effect appears to be due to increased surface roughness rather than to the removal of paint from the pile surface. Key words: adfreeze strength, backfill, permafrost, piles, pile surface treatment, salinity.