Numerical simulation of the lateral load test on piles through a parametric analysis

Pile foundations are utilized to transfer load from the superstructure to the soil mass when the surface layer of the ground exhibits low load-bearing capacity. For an axially loaded pile, the load is transmitted to the soil through lateral friction at the soil-pile interface and via tip resistance. However, these elements are subject to significant lateral forces in addition to vertical ones. The resistance of piles to lateral loads depends on boundary conditions, stiffness, and concrete strength of the pile, as well as soil type, soil stiffness, and soil strength. Several models are employed to analyse laterally loaded piles, including soil modelling using nonlinear springs, commonly known as p-y curves. This article aims to investigate the impact of pile geometric properties, soil type, and the chosen model on simulating soil-pile interaction on the structural performance of a pile embedded in soil subjected to a transverse load. The study encompasses the variation of three pile diameters (60 cm, 80 cm, and 100 cm), three pile lengths (5.5 m, 10.5 m, and 15.5 m), and three soil types (soft clay, stiff clay, and moderately compacted sand). The effects of diameter (D), pile length (L), slenderness ratio (L/D), and soil type on the lateral response of the pile are examined. Additionally, an analysis is conducted regarding the influence of linear and nonlinear (p-y curves) Winkler models on simulating soil-pile interaction. The presented results indicate that the foundation behaviour, when considering soil-pile interaction, is contingent upon various factors and should be rigorously assessed by designers. It is noteworthy that, depending on the soil type, soil modelling using horizontal linear springs yields acceptable results, obviating the need for a nonlinear model. However, when soil particles exhibit friction or low cohesion, a careful analysis of soil parameters and the chosen model for simulating soil-pile interaction is warranted, with numerical simulation via FEM in conjunction with lateral load testing recommended to determine the optimal method.