Retracted: Relationship between Installation Torque and Axial Capacities of Helical Piles in Cohesionless Soils

Abstract

With the rapid growth of the helical piling industry, reliable installation torque estimates and measurements become crucial. This paper presents a theoretical model developed to estimate the torsional resistance of cohesionless soils to helical pile installation. The theoretical torque model was verified using installation records collected from different sites. The paper also highlights factors that affect helical pile installation including soil properties, fluctuation in groundwater levels, shape of pile shaft, pile geometry, and method of helical pile installation. Torque factors, Kt, commonly used in the industry to correlate between installation torque and pile capacities, were also assessed and presented in the paper. The results of the study indicated that the torque factor is a function of the load path (i.e., tension or compression). Therefore torque factors in compression and tension, Kc and Kt, were formulated and presented in the paper.