A full-scale study is reported of the response of four pairs of piles of 150 mm through 620 mm diameter, bored piles drilled with slurry, continuing-flight auger-cast pile (CFA), and a fulldisplacement pile (FDP). One of each pair was equipped with an Expander Body to increase the pile-toe diameter, preload the pile axially, as well as bring about a stiffer pile toe and, thus, achieve a stiffer pile. All piles were constructed to 9.5 m depth in a loose to dense silty to dense sand. The EB-equipped piles were supplied with bidirectional cell immediately above the EB (depth 8.3 m). Static loading tests performed on all piles showed that the expansion of the EB markedly increased the pile toe stiffness. This, not just by increasing the pile toe area, but also by preloading the soil underneath the pile toe and increasing the shaft resistance acting around the 1.5 m long EB.
Subjects: Bored piles, CFA piles, Full Displacement piles, static loading test, pile-toe augment.
Author: Bengt H. Fellenius, Dr.Tech., P.Eng., K. Rainer Massarsch, Dr. Tech., Mario Terceros H., Eng. and Mario Terceros A.
Publisher: DFI, EFFC