SHAFT RESISTANCE OF PILES CLOSE TO BACKFILLED SAND COLUMNS

Abstract

In most reconstructions, existing old pile foundations are removed to construct new foundations. After removing the existing pile, the hole is backfilled, but there are issues such as different conditions from the surrounding ground. We report axial compressive loading model tests to investigate the shaft resistance of piles close to backfilled sand. In these model tests, the sandy ground is prepared in a chamber and a backfilling process is simulated, with varied backfilled sand density. The tests reveal that the maximum shaft resistance of the pile depends on the density of the backfilled sand. A numerical finite element method analysis is also performed to examine shear failure in the soil near the pile, which contributes to the shaft resistance mechanism of the pile. When the conditions of the backfilled sand are different from those of the soil, the shear stress of the soil near the pile is affected in both the backfilled sand area and the soil opposite the backfilled sand, and the shape and thickness of the shear band that occurs near the pile changes.