Method for improving ground by high-pressure injection agitation method and special head used for this ground improvement method

摘要

PROBLEM TO BE SOLVED: To provide a ground improvement method by a high pressure injection agitation method that shortens a construction period and also reduces construction costs by easily creating a wall type solidification improvement body in the foundation.SOLUTION: A ground improvement method by a high pressure injection agitation method that improves the foundation by creating a solidification improvement body T in the foundation by inserting a pipe rod 2 into the foundation and injecting a hardener from an injection nozzle 34 of a special head fitted to the pipe rod 2 at a high speed under high pressure includes: providing the special head 6 with three injection nozzles 34 apart in a substantially lateral direction; performing cross injection of hardeners by the three injection nozzles 34 so that the hardeners cross one another at destinations of injections in slight different injection directions; rotating and carrying out the cross injection of the hardeners from the three injection nozzles 34 by a predetermined angle to a predetermined range without any vertical movement; then lifting the pipe rod 2 upward by a predetermined length and then rotating and carrying out the cross injection of the hardeners from the three injection nozzles 34 by a predetermined angle to a predetermined range without any vertical movement; and repeating the lifting and cross injection upward so as to create the wall type solidification improvement body T in the foundation.