Pullout Capacity of Screw Piles in Sandy Soil

Abstract

In this study, the behavior of square screw piles models 5´5 mm² embedded in sandy soil was investigated. The sandy soil layer 400 mm thickness was compacted into four sub-layers in a steel container with diameter 400 mm in size. Sandy soil layer was compacted into three relative densities 30%, 60% and 90%. Model tests are performed with screw pile length 100 mm, 200 mm and 300 mm and with helix diameter 15 mm and 20 mm. Also, one helix and double helices were used for these piles. This study revealed that the pullout force of screw piles increases with increasing depth of embedment in the sandy layer, relative density of sandy soil, helix diameter and number of helices plates. The increase in pullout forces of screw piles are 22–40% and 41–70% when relative density of sandy soil changes from loose state to dense state respectively.