ABSTRACT
Laboratory model pile tests were performed to evaluate ultimate uplift capacities and critical relative displacements (CRD). The uplift capacities are significantly affected by pile surface conditions and the depth of pile embedment. The test results show that the CRD is not constant and is independent of the pile size, but is most closely related to the magnitude of the critical pile-soil adhesion along the pile shaft. An empirical relationship between these two quantities was established from the experimental results. This empirical equation was then verified by comparison with the reported results of conducting field tests on piles. A method has been proposed to calculate the value of adhesion coefficient for smooth metal piles in clay.
