Assessment of piles’ resistance driven sequentially in fine-grained soils using pile load tests

This paper presents a field pile load test program conducted on four 0.36 m closed-end steel pipe piles with lengths ranging between 11 and 13 m installed in fine-grained soils. Subsurface investigations with standard penetration tests and cone penetration tests with pore pressure measurements were performed at the site. Three pushed-in piezometers at incremental offsets from the piles were also installed to monitor pore water pressure changes during and after the installation of piles. Several dynamic load tests were performed at different times to observe the change in pile resistance. A static load test was also performed on one of the piles. Some load test results showed an unexpected decrease in the resistances of some piles with time. The study showed that construction activities, e.g., installation of other piles, disturbs the soil and groundwater conditions which can significantly affect the pile resistance measured during load tests. This investigation revealed that pile driving and restrikes should be scheduled such that the effect of construction activities on load tests results will be avoided or minimized.