THREE DIMENSIONAL ANALYSIS OF SINGLE LATERALLY LOADED HELICAL PILES IN COHESIONLESS SOIL

Abstract

Helical pile is a deep foundation system consist of steel central shaft with a series of attached helical plates at particular locations installed by rotational torque technique. The advantages of helical piles enables them to be widely used for different types of onshore and offshore structures and various application functions from typical deep foundation to ground anchoring system. This research focused on the performance of laterally loaded single helical pile in cohesionless soils using finite element program Plaxis 3D. In order to assess adequacy of the numerical model which is used in conducting parametric study. The results of four field lateral load tests for different helical piles geometry were compared with the results of the numerical model and the comparisons show a good agreement. This study presents a simulation for predrilling process of helical piles by two different approaches. The first approach was conducted by creating a surrounding zone around helical pile with reduced strength and stiffness and the second approach was conducted by using interface element around helical pile. In addition, a parametric study was performed considering cohesionless soils in order to highlight the role of some parameters related to both pile and soil on the behavior of helical piles under lateral loading. The soil strength range from loose to dense. The piles configurations include straight shaft pile and helical piles with 1,2,3,4 helices. The effect of number of helices, rigidity of piles, slenderness ratio, sand densities on pile head deflection and lateral resistance of helical piles were evaluated. Moreover, the strain wedge zone mobilized around straight shaft pile and helical piles including the