Evolution of pile shaft capacity over time in marine soils

Abstract

Driven pile foundations may experience an increase in bearing capacity overtime after installation which is referred to as pile set-up or freeze. Field observations have demonstrated that pile set-up could be substantial and the evolution of pile shaft capacity may continue for an extended time after pile installation. This paper presents results of a series of pile load tests conducted on medium-scale steel and concrete pile foundations driven into marine sensitive clay in Gloucester, Ontario. The piles were tested instantly after driving to measure their initial bearing capacities, and were tested repeatedly over different elapsed times to study the evolution of pile shaft capacity over time. The excess pore water pressure around the pile was also monitored by a piezometer. The pile performance analysis was established by monitoring the shaft capacity of driven model piles over 1 month in soft marine clay. The average pile capacity measurements for both steel and concrete piles showed approximately 4.5–5.5 times increase in the pile capacity 30 days after initial driving depending on the type of the piles used.