Journal Article

Effects of installation advancement rate on helical pile helix behavior in very dense sand

Annicchini, Matheus Morato, Schiavon, José Antonio, Tsuha, Cristina de Hollanda Cavalcanti

2023

Overview

During installation, the helical pile should penetrate into the ground at a rate equal to one helix pitch per rotation to prevent additional soil disturbance, as usually recommended in installation guides; however, in the field this is frequently difficult to achieve. To have a better understanding of the effects of the advancement rate (AR) on the installation torque and helix bearing capacity, six calibration chamber tests were performed on an instrumented single-helix pile installed in very dense sand using three different AR values (0.8, 1 and 1.2). For the range tested, the results indicated that AR affects the uplift and compressive capacity of the pile helix. A reduction in compressive capacity of 24% on average was observed for AR of 0.8, compared to the recommended pitch matched installation (AR = 1), while for AR of 1.2, the compressive capacity increased 12% on average. In uplift, the capacity variation was about − 26% and + 6%, respectively, for AR of 0.8 and 1.2 compared to the pitch matched installation case. The effect of AR was also observed for the capacity-to-torque factor related to the helix portion of a deep helical pile and suggests the necessity for monitoring AR to ensure the applicability of the torque factor for pile capacity control.

• Publisher: Springer Nature B.V
• Subject: Bearing capacity / Calibration / Civil engineering / Piles / Sand / Sand & gravel / Torque / Uplift