Forensic investigation of laterally loaded screw pile using finite element analysis

Abstract

Recent studies on the screw piles indicate that it has huge potential to resist the lateral loads. Large diameter screw piles may be useful to support wind turbines where it could be subjected to a significant amount of lateral loads due to wind. In this paper, a forensic investigation is conducted to determine the failure behaviour of a laterally loaded screw pile installed in sand using three dimensional finite element analysis. Lateral behaviour of screw piles (single and double helix) are backpredicted in terms of lateral load-deflection curves and the results are compared with the measured field tests data. In the analysis, the soil is modelled using Mohr-Coulomb criteria and the shaft and helix are modelled as a linear elastic material. The interface between the shaft, soil and the helix is modelled using the master-slave approach available in ABAQUS. The numerical results for the single-helix pile are found to be in good agreement with that of the field tests data. However, for double helix pile, the backpredicted lateral load-deflection behaviour deviates from the field tests. This deviation may be due to the soil disturbance caused during installation which is not considered in the present study. The ultimate lateral capacity of the screw pile is also backpredicted using the finite element analysis and the available empirical and analytical relationship. The results are finally compared with that of the field tests data. Forensic study shows that the available empirical and analytical relationships highly overpredicts the ultimate lateral capacity and is valid only for rigid/short screw piles. Therefore, future study should focus to develop improved relationships involving flexible/long screw piles. Copyright � Soil Mechanics and Geotechnical Engineering, ARC 2019.All rights reserved.