Shaft capacities of closed-end piles under load reversals in sand

Since a wide range of opinions exists on axially loaded friction piles in sand a further evaluation and determination of the mechanisms involved with pile shaft capacities has been undertaken. A series of model pile load tests have been carried out in a geotechnical centrifuge to determine the effects of continuous load reversals. Axial compression and tension tests were performed on closed end pipe piles in a medium to dense dry silica sand. Both the end bearing and the total pile capacity were simultaneously measured to enable direct calculation of the shaft capacity. Pile loads and displacements were measured, as was the pile's inclination off vertical. With this information and the soil properties obtained within the laboratory, back calculations were performed using various methods to theoretically determine the pile shaft capacities. The theoretical values were then compared with the pile model data at prototype scale. (Abstract shortened by UMI.)...