Patent ID: 8221034

Claim:
A method of forming an aggregate pier comprising the steps of: (a) driving downwardly into pier site soil a tapered mandrel having an open lower end initially covered by a cap to form a downwardly tapered cavity to a desired depth for said aggregate pier while supporting a sidewall of the cavity; (b) moving the tapered mandrel upwardly to a top of said cavity so as to separate said cap from said open end of the mandrel and withdraw said cap while delivering loose aggregate through said open end of the mandrel and depositing said delivered aggregate to the cavity so as to support said sidewall below said upwardly moved mandrel; (c) driving downwardly into said deposited aggregate a tapered mandrel having a blunt lower end surface so that said blunt lower end of the mandrel compacts said deposited aggregate and densities said soil; (d) moving said tapered mandrel having the blunt lower end surface upwardly from said compacted aggregate and depositing additional loose aggregate in said cavity; and (e) repeating said steps (c) and (d) until a pier component of a desired height is formed.