Comparative Analysis of the Performance of Helical Piles and Conventional Concrete Piles in Different Soils Using Hardening Soil Model in PLAXIS 3D

Abstract

This study conducts a detailed numerical calculation of the axial behavior of helical piles (HP) and normal concrete piles (RCC) under extremely wide soil conditions using PLAXIS 3D with the hardening soil model (HSM). 144 finite element models were developed by systematic variation in pile length (10-20 m), diameter (450-750 mm), and helix configurations in the soil profiles of soft, medium, and stiff clay; loose, medium-dense, and dense sand; and layered stratifications. Results indicate that HP is always better than RCC piles at shallow to medium embedment depths (10-15 m) and smaller diameters (450-650 mm), with settlement reductions by 10-22% in clay and 12-20% in loose to medium-dense sand. In dense sand and hard clay, the differential performance is lessened considerably, with differential performance decreasing below 5% at larger diameters (750 mm) and depths of installation (20 m), where settlement behavior is governed mainly by pile length. HP in strata has 8-20% lower settlements than RCC piles, with maximum advantages in clay-sand profiles due to the combined effect of helix plates and end-bearing resistance. Overall, the findings indicate that while RCC piles remain suitable for application in dense soils at increased depths, HPs provide enhanced serviceability in soft and stratified soils, which indicates their potential to be a sustainable and efficient foundation choice in unfavorable geotechnical conditions.