Investigating the Impact of Geometrical Properties of Helical Piles Buried in the Layered Soil on the Compressive and Tensile Load-Bearing Capacity

Helical pile engineering relies on various factors and components, to the extent that the simultaneous effect of several parameters can present distinct results. In this article, considering the significance of soil layering in pile performance, the simultaneous impact of geometric parameters of helical piles in two-layer soils (clay over sand) on the compressive and tensile capacity of helical piles has been explored using the finite element method. Moreover, the failure mechanism of the adjacent soil has been investigated considering the geometric characteristics of the pile. Initially, a set of loading experiments conducted in the field part to analyze the compressive load-bearing capacity of helical and driving piles will serve as a basis for understanding real-world performance and validating numerical simulations. In the subsequent part, in a numerical study, various geometric parameters affecting the capacity of helical piles, such as diameter, spacing between the spokes, and number of spokes, are investigated. The field study results indicate that helical piles will exhibit a compressive load-bearing capacity approximately 7.1 times that of driven piles with a displacement equivalent to 5% of the pile diameter. In the numerical analysis, the results indicate that soil layering can impact both the compressive and tensile capacity of helical piles and induce alterations in the soil failure mechanism around the piles.