Abstract: A method and apparatus for forming a support aggregate pier having compacted aggregate lifts in a soil matrix, includes an elongate, hollow tube with a bulbous leading end bottom head element that is forced or lowered into the soil matrix. The hollow tube includes a mechanism for releasing aggregate from the lower head element of the tube as the tube is lifted in predetermined increments. The same hollow tube is then lowered or pushed in predetermined increments to vertically compact the released aggregate in thin aggregate lifts, while forcing a portion of the compacted aggregate transaxially into the soil matrix at the sidewalls of the cavity. The process may be repeated to form a series of compacted aggregate lifts comprising an aggregate pier or the process may include forming only a single lift for the aggregate pier while densifying adjacent matrix soils and imparting lateral stress in these soils.

Abstract: A method and apparatus for forming a support aggregate pier having compacted aggregate lifts in a soil matrix, includes an elongate, hollow tube with a bulbous leading end bottom head element that is forced or lowered into the soil matrix. The hollow tube includes a mechanism for releasing aggregate from the lower head element of the tube as the tube is lifted in predetermined increments. The same hollow tube is then lowered or pushed in predetermined increments to vertically compact the released aggregate in thin aggregate lifts, while forcing a portion of the compacted aggregate transaxially into the soil matrix at the sidewalls of the cavity. The process may be repeated to form a series of compacted aggregate lifts comprising an aggregate pier or the process may include forming only a single lift for the aggregate pier while densifying adjacent matrix soils and imparting lateral stress in these soils.