GROUND IMPROVING BODY FORMING METHOD AND APPARATUS

PROBLEM TO BE SOLVED: To provide a ground improving body forming method the construction period of which is shortened by simultaneously executing insertion of a steel pipe and formation of a ground improving body and which is excellent in economical effect, and a ground improving body forming apparatus. SOLUTION: The ground improving body forming method comprises the steps of simultaneously advancing a pipe 6 having a pipe bit 5 provided at the tip end and a hardening material jetting rod 4 piercing the pipe 6, moving only the rod 4 backward by a specified distance after completion of boring to align hardening material jetting holes and sludge suction holes of both the pipe 6 and the rod 4 to one another, moving the pipe 6 and the rod 4 backward with jetting the hardening material into the ground and discharging the sludge for the primary formation, then advancing only the pipe 6 to align the holes of the rod 4 and other hardening material jetting holes of the pipe with the sludge suction hole for the secondary formation and repeating the above described primary formation and secondary formation to form the ground improving body with the pipe inserted. The ground improving body forming apparatus is also disclosed. COPYRIGHT: (C)2005,JPO&NCIPI