Load-settlement and skin friction behaviour of piles in dry sand: experimental and numerical study

Abstract

The objective of the study was to evaluate the load-settlement behaviour of piles, both with and without the inclusion of a sponge material at the pile base to minimize tip resistance and enhance skin friction. Laboratory experiments were conducted to examine the response of pile models subjected to axial loads in dry sand. Physical scaling principles were meticulously applied to determine model pile dimensions and tank size, which were dependent on the material properties of the model. The modelled pile, fabricated using aluminium, had an external diameter of 60 mm. The investigation encompassed pile length-to-diameter ratios of 4 and 6. Axial loads and skin friction were quantified using strain gauge measurements. Furthermore, numerical mod elling of the experimental tests was conducted using PLAXIS 3D, where the sand was represented using a hardening soil model and the pile was modelled elastically. Triaxial tests were performed on sand samples to characterize soil properties, and laboratory tests were executed to ascertain pile parameters. To account for soil pile interaction, interface elements were introduced between the soil and pile. Multiple parametric studies were undertaken by varying pile configurations, and subsequent numerical results were systematically compared with the experimental findings. Numerical models correctly represented pile’s behaviour under various loading cir cumstances. Less than ± 5% of displacement difference was detected between experimental and numerical findings, demonstrating acceptable agreement between the two methods.