Settlement based load capacity curve for single helix helical pile in c - ϕ soil

Abstract

Helical piles are getting increasingly popular for lightweight engineering applications. Currently, the helical pile is mostly designed with torque capacity; however, it cannot explain the foundation's anticipated settlement. The current study developed a settlement-based design technique to determine the capacity of a single helix in small diameter helical piles. A three-dimensional nonlinear finite element analysis (FEA) was conducted using PLAXIS 3D. At first, the numerical models were calibrated and verified using load testing data from representative soil properties and realistic modeling assumptions. Then a parametric study was extended to determine the load settlement curve in different c- ϕ soil types, along with varying helix and shaft configurations. The load-deformation curves were grouped to develop multiple load capacity curves. Finally, the load capacity curve was validated by load test data. The range of calculated vs measured (from load tests) capacities (Qc/Qm) is 0.68 to 2.67, where the mean Qc/Qm is 1.10.