Relation between axial load variation and vertical displacement at pile head during large earthquake

抄録

During large earthquakes, pile heads are subjected to repeated axial load variations owing to the overturning moments caused by the inertial forces of the superstructure. Such axial load variations may cause the residual and unequal settlement and damage to superstructures and lifelines. However, the characteristics of pile settlement during large earthquakes remain unknown. Therefore, this study investigated the settlement characteristics of pile foundations during large earthquakes using a dynamic centrifuge test on a soil–pile–superstructure system. The following results were obtained. (1) The residual settlement of piles caused by a large earthquake could be estimated using the maximum axial load variation, skeletal curve, and correction factor. (2) The unequal settlement between the front and rear piles could be estimated based on the relationship between the dynamic vertical displacement and the axial load variation instead of the skeletal curve. Moreover, it was found that the unequal settlement based on the skeletal curve may have been significantly overestimated