Patent ID: 7488139
Filing Date: 2009-02-10
Classification: E02D

Abstract:
1. A method of constructing aggregate piers comprising the steps of: forming an elongated cavity in a ground surface, said cavity having a sidewall and a generally uniform cross-sectional area; placing a lift of aggregate into the cavity with a lift thickness approximately equal to a distance across the cavity; tamping the lift with a pyramidal or conically shaped tamper head having a substantially hollow portion and a top or base approximately equal to said cross-sectional area of the cavity, and a bottom or tip no more than about 20% of the area of the top or base, to increase the lateral stresses in the sidewall of the cavity, wherein the tamper head is sized and configured to connect to and be manipulated by a tamper rod, mandrel or shaft that connects to and communicates a mechanized force from a power source to the tamper head for delivery to the lift of aggregate; and repeating the placing and tamping steps with successive lifts.