Load–Displacement Behavior of Inclined Screw Piles in Sand under Different Centrifuge Acceleration Levels

ahmed hussein

doi:10.71229/90d6hn30

Authors

Ahmed A. Hussein School Building Department, Ministry of Education, Baghdad, Iraq. https://orcid.org/0009-0003-5040-9031

DOI:

https://doi.org/10.71229/90d6hn30

Keywords:

screw pile, helical pile, uplift capacity, centrifuge modelling, inclined tension, sandy soil

Abstract

This paper presents a study of the uplift behaviour of screw pile models embedded in dry sandy soil under inclined tensile loading by small scale and centrifuge modelling. The tested screw pile had a helix diameter of Dh=2d, a spacing ratio of S/Dh=3, and an embedment depth of 400 mm. Tests were conducted at a relative density of 55% under 1g, 5g, 10g, and 15g acceleration levels. Three tensile load inclination angles, 30∘, 60∘ and 90∘, were considered. A pipe pile without helices was tested as a reference case to evaluate the improvement ratio (Q/Qo). The ultimate uplift capacity was determined using a displacement-based criterion corresponding to 10% of the helix diameter. The results showed that uplift capacity increased with both load inclination angle and centrifuge acceleration level. The maximum capacity was recorded for vertical tensile loading (90°) reaching 240 kN at 15g. The improvement ratio also increased with the acceleration level and load angle with the maximum value of 20.8 at 90∘ and 15g. The results indicate that the application of the helical plates considerably improves the tensile strength, especially in the vertical loading case and higher stress.

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