Displacement Grouted Columns (DGCs)
Displacement Grouted Columns (DGCs) provide both ground improvement and high capacity in a single deep foundation element. These columns can achieve higher capacity than augercast or large-diameter bored piles, without generating all the spoils.
DGCs are installed by screwing the injection tool into the ground using a rotary hydraulic drill rig (base machine). Upon reaching the designed depth the stem is unscrewed and grout/concrete is pumped under pressure displacing the ground around serving to increase lateral stresses (friction interface) in the soils. The screwing and unscrewing of a single segment of auger (helix) leaves a spiral space within the adjacent soil which is simultaneously pressure filled as the stem is withdrawn.
Depending on the helix diameter, the lateral soil displacement leaves behind a geometric element with an exterior “corrugated” shape. Such geometric configuration, coupled with pressure injection, forms the ideal displacement column with superior frictional properties and end bearing capacities. Installation imparts no impulse or vibration.