Numerical Analysis of Installation Performance and Uplift Bearing Capacity of Helical Piles in Clay

Helical piles are widely used for their low installation noise, low disturbance, recyclability, and increased load-bearing capacity. This study investigated the effects of installing multiple-plate helical piles on the surrounding soil using the coupled Eulerian-Lagrangian finite-element method. The comprehensive parametric study was carried out using the advancement ratio, the spacing ratio, the ratio of helix plate diameter to shaft diameter, the embedment depth ratio, and the soil strain softening parameters. The influence on the uplift capacity was then investigated by mapping the remolded soil strength field, derived from the coupled Eulerian-Lagrangian computation, into a numerical model for finite-element limit analysis. The results reveals that the penetration of single- and multiple-plate helical piles affects the soil strength in a cylindrical region with a radius of 0.7 times the helix plate diameter and a height of the penetration depth surrounding the pile. Although strain softening parameters have a significant impact on soil strength, they do not alter the range of soil strength disturbance. The impact of embedment depth ratio on uplift bearing capacity is most notably significant. © 2024 American Society of Civil Engineers.