GROUND IMPROVEMENT METHOD BY HIGH PRESSURE INJECTION AGITATION METHOD, AND SPECIAL HEAD USED FOR GROUND IMPROVEMENT METHOD

• Main Authors: TANAKA HATSUICHI, ISOTANI SHUJI, OKADO MASANORI, IMAKIRE KENICHI, NAKAJIMA YOSHITAKA
• Format: Patent
• Language: English; Japanese
• Published: 29.10.2015
• Subjects: EMBANKMENTS; EXCAVATIONS; FIXED CONSTRUCTIONS; FOUNDATIONS; HYDRAULIC ENGINEERING; SOIL SHIFTING; UNDERGROUND OR UNDERWATER STRUCTURES

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. 【課題】地盤中に壁形の固結改良体を容易に造成できるようにし、工期の短縮を図ると共に工費の低減も図る高圧噴射攪拌工法による地盤改良方法を提供する。【解決手段】地盤中に管ロッド２を挿入し、管ロッド２に取り付けた特殊ヘッド６の噴射ノズル３４から硬化材を高速高圧で噴射して地盤中に固結改良体Ｔを造成して地盤を改良する高圧噴射攪拌工法による地盤改良方法において、特殊ヘッド６に３個の噴射ノズル３４を略横方向に離間して設け、この３個の噴射ノズル３４においてそれぞれ噴射方向を僅かにずらして噴射した先で硬化材が交差するように硬化材を交差噴射させると共に、この３個の噴射ノズル３４からの硬化材の交差噴射を所定の角度だけ回転して所定の範囲に上下に移動することなく行い、その後、管ロッド２を所定の長さ上方に引き上げてから、３個の噴射ノズル３４からの硬化材の交差噴射を所定の角度だけ回転して所定の範囲に上下に移動することなく行い、これを上方に向かって繰り返し行うことにより、地盤中に壁形の固結改良体Ｔを造成する。【選択図】図８