A COMPARATIVE STUDY ON THE RESISTANCES OF BUCKET FOUNDATION IN SAND WITH DIFFERENT INSTALLATION METHODS

Abstract

Model tests have been performed to investigate the vertical, horizontal and cone tip resistances
of bucket foundations embedded in sand with different installation methods; suction force by pump and jacking
force by actuator. Micro-cone penetrometer was used to evaluate the variation of the effective stress inside pile
after model pile installation. As a result, in vertical pull-out test, the pile installed jacking force method shows
3 times larger resistance than installed suction force method. In horizontal pull-out test, the ultimate horizontal
capacity and the slope of load-displacement curve for the model pile installed by suction force were decreased
by 22% and 40% respectively compared to the pile installed by jacking force. In cone penetration test, inside
cone tip resistance of the pile installed by suction force shows about 40% smaller than that installed by jacking
force. It is because the effective stress was reduced due to upward seepage of inner pile in sand by suction
force. Therefore, we can see that the effect of installation method on bucket foundation has to be considered to
investigate the behavior of it experimentally.