METHOD AND APPARATUS FOR CREATING SUPPORT COLUMNS USING A HOLLOW MANDREL WITH UPWARD FLOW RESTRICTORS

摘要

A system and method for installing aggregate piers is provided. A cylindrical hollow mandrel is driven to a desired depth. Aggregate is fed through the mandrel in steps. The mandrel is raised and driven to tamp the aggregate. Physical members in a tamping head of the mandrel allow aggregate to remain in a cavity formed by the mandrel, and prevent aggregate from entering the mandrel during driving.