The term friction pile is derived from the very means in which the pile develops its resistance to uplift or compression forces. They are a full-displacement piles consisting of a concrete-filled, steel pipe with a closed-end conical tip. This proprietary conical tip, welded to the bottom of the steel pipe, is used to advance the pile into the ground. The full-displacement pile pushes soil into the surrounding formation as the pile is drilled in place using high torque.
Friction piles offer unique performance characteristics in terms of limited noise pollution, low vibration and limited spoils generation. Noise levels are limited to the low hum of the drill rig diesel engine. No vibration can be paramount when working in close proximity to existing structures.
Friction piles are a relatively simply installation method and generally lead to highly efficient work sequences which can expedite project schedules and lower project costs.
Unlike typical drilled piles where the spoils are extracted, friction piles displace spoils in close proximity to the advanced casing. This increases the density of the immediate area and increases the friction or load bearing characteristic of the ground. Just as a screw torques into a piece of wood pushing aside wood silvers, so too do friction piles, pushing aside spoils but retaining a certain pressure that is pushing back on the pipe. In addition, Coastal Drilling East utilizes a proprietary conical tip that was developed to minimize spoils and ground heave while maximizing capacity. Little to no spoils generated make the use of friction piles ideally suited for sites having contaminated subsurface.