By Antonio Marinucci and Marco Chiarabelli
There have been several new advancements in the last three generations of drilled displacement piles (DDP). Dan Brown is a civil engineer at Dan Brown & Associates stated the torque and crowd required to construct a drilled displacement pile is substantial…the energy required to install the pile is related to the resistance of the soil to the displacement, and so the piles are often installed to a depth that is controlled by the capabilities of the drilling rig. For the installation of conventional DDPs, Soilmec hydraulic drilling/piling rigs are capable of producing high torque and large crowd forces, which are needed for the desired pile diameters and depths.
The early methods (prior to the 1970s) used to construct displacement piling (“first generation” piles) focused on either soil removal during the advancement of the tool or on the insertion of large casing into the ground during advancement. Moreover, relatively low torque (50-100 kN-m or 37,000 to 74,000 ft-lb) was required by the drilling equipment to perform these piles, but the production was slow. The methods comprising these first generation piles include Atlas piles, DeWaal piles, Franki VB piles, Fundex piles, and Olivier piles. The next version of displacement piles emerged during the 1970s and improved upon the production rate achievable during advancement by adding partial auger flighting near the bottom of the tooling. Methods comprising this second generation of displacement piling include Pressodrill pile, Tubex pile, SVB pile, and SVV pile. Since the 1980s and even more during the last two decades, there has been advancements in the tooling (e.g., increased diameters, and design of the flights and body to increase production), techniques (e.g., reduced vibrations, spoils, and noise), and drilling equipment (e.g., greater torque and pulldown crowd force, which permit larger diameters and greater depths). Methods comprising this third generation of DDP include: Omega pile, Berkel Auger Pressure Grouted Displacement (APGD) pile, Menard controlled modulus columns, Trevi Discrepiles, and displacement piles constructed using the Soilmec’s patented new compaction technology called Traction Compacting Tool (TCT) to reduce the crowd force required to perform displacement piles: It requires small size piling rigs (or it may enlarge their field of application) because the displacement process takes place during the tool extraction phase. To learn more about Soilmec’s TCT technology, contact us today.