Evolution of Pile Shaft Capacity over Time in Soft Clays (Case Study: Leda Clay)

This thesis presents a comprehensive experimental investigation to examine the evolution of pile shaft capacity over time. This phenomenon is observed in piles driven into soft clays, which referred to as pile set-up/freeze. The first phase investigates the behavior of pile-soil interface over time using a modified direct shear test at two loading rates of slow and fast. The second phase involved a series of pile load testing was performed on steel and concrete piles driven into Leda clay in a test site. The piles were tested immediately after driving to measure their initial bearing capacities, and were tested repeatedly over different elapsed time to study the change in pile shaft capacity. The excess pore water pressure around the pile was also monitored by a sensor. The average pile capacity measurements indicated that there is approximately 4.5-5.5 times increase in the pile capacity after 30 days from the initial day.