Laboratory Modelling and Analysis of Displacement Pile in Different Geometries on Alluvial Soils

Abstract

Alluvial soils are weak soils that require precautions and have disadvantageous engineering characteristics such as low shear strength and bearing capacity, high void ratio, and settlement potential. Different foundation systems are preferred for structures built on these soils to transfer the load effects safely. Pile foundations as deep foundations are classified depending on various parameters such as; material property, application method, and load-bearing method. In this study, cylindrical and square concrete piles with different cross-sections and lateral areas were placed in the alluvial soil. The natural alluvial soil taken from İzmir province, Balatcik location was placed in a displacement-controlled pile model unit with a unit weight of ≈ 17 kN/m3. The manufactured concrete piles were driven into the soil with a Standard Proctor hammer. Tensile effects were applied at different time intervals to examine long-term and short-term behavior. As a result of experiments, load-displacement (py) and displacement-time (y-t) graphs were drawn. When the displacement piles were examined under long-term tension, it was seen that the cylindrical piles displaced the most. Square piles with the same cross-sectional area as cylindrical piles made less displacement. All studies were modeled 1:1 as numerical and compared with experimental results. Numerical investigations revealed that under long-term effects, the highest displacements were observed in cylindrical piles, while the lowest displacements were in square piles with equal cross-sectional area as cylindrical piles. Under short-term tension effects, investigations showed that the highest bearing capacity, according to both experimental and numerical results, was in square piles which have an equal cross-sectional area with cylindrical piles. Studies showed that the experimental and numerical results for pile behavior were compatible.