Patent ID: 6988856
Filing Date: 2006-01-24
Classification: E02D

Abstract:
1. A method for forming a large diameter, subterranean soil cement column in material located in a subterranean earth situs utilizing a large diameter soil processing tool with a pilot in conjunction with a preformed sacrificial guide, comprising the steps: forming a sacrificial guide by advancing and rotating a small diameter soil processing tool into said situs to break said material into pieces, said small diameter soil processing tool forming a hole as it advances; while advancing said small diameter soil processing tool into said situs, introducing a cement slurry into said pieces from said tool at a velocity sufficient to hydraulically divide said pieces into particles and mix said cement slurry with said particles to form a soil-cement slurry, said soil-cement slurry containing cementitious solids, soil particles and free water; withdrawing said small diameter soil processing tool from said situs; while withdrawing said small diameter soil processing tool, rotating said tool at a rotational speed to exert a centrifugal force by said tool upon said soil-cement slurry in excess of two G's, whereby said centrifugal force causes the solids of said soil-cement slurry to migrate further from the center of said hole than said free water to form a first cylindrical region at the outer edges of said hole and a second cylindrical region at the center of said hole, said first region having a smaller proportion of free water than said second region; allowing said mixture in said hole to set up; advancing said pilot of said large diameter soil processing tool into said second region of said sacrificial guide; driving said tool downwardly, and forming a large diameter soil-cement column by physically and hydraulically dividing said material into particles and mixing cement slurry with said particles; and breaking said sacrificial guide with said large diameter soil processing tool, whereby said sacrificial guide fragments are mixed into and become part of said soil-cement column formed by said large diameter soil processing tool.