Vertical stress variation induced by helical pile installation in very dense sand
Vertical stress variation induced by helical pile installation in very dense sand
Helical piles have emerged as an effective solution for supporting power generation turbines in offshore wind farms. This is primarily due to their high tensile resistance, provided by the anchor effect of the helices, as well as the minimal disturbance they cause to the marine environment during installation. Understanding soil behavior during helical pile installation is crucial, as the process significantly influences the piles tensile capacity through the disturbances generated in the surrounding soil. This study examines the variation of vertical stresses around two single-helix pile models installed in a large calibration chamber filled with very dense dry sand. The piles featured 42.2 mm diameter shafts with helix diameters of 127 and 170 mm, embedded to a depth of 1000 mm. Vertical stresses were monitored using stress transducers installed at depths of 500, 750, 1000, and 1250 mm, each located 300 mm radially from the piles central axiscorresponding to 1.8D and 2.4D from the longitudinal axes of piles 2 and 1, respectively, where D is the pile helix diameter. Results showed a modest increase in vertical stress as the helix approached each sensor depth, following the passage of the helix, the stresses gradually return to levels similar to those recorded prior to installation. Additionally, increasing helix diameter from 127 to 170 mm had negligible effect on vertical stress at the measured horizontal distance from pile axis, with both pile configurations displaying similar magnitudes and depth-related trends.
Christopher Fonseca da Silva; Jussara Ferreira Michette; Cristina De Hollanda Cavalcanti Tsuha
11th International Conference on Physical Modelling in Geotechnics (ICPMG2026)
Session 6: Onshore and offshore foundation systems
https://doi.org/10.53243/ICPMG2026-138