PURPOSE: To reduce a construction period by inserting a plurality of perforated pipes into the ground, injecting grouting chemicals into the ground through one part of the perforated pipes and, at the same time, generating negative pressure in part of the other perforated pipes to suck chemicals grouted thereinto.

CONSTITUTION: A plurality of holes 11 are perforated in the circumference of a perforated pipe 1, the front end thereof is closed, and closed valves 2 are provided to the basic ends. After that a grouting pump 4 is connected to the basic end of a perforated pile 1a through a hose 3, and a draining pump 5 is connected to the basic end of a perforated pipe 1b through a hose 3. Then, the pump 4 is operated to convey chemicals to the inside of the perforated pipe 1a, and the chemicals are grouted into the peripheral ground from a plurality of holes 11 and is impregnated. The pump 5 is operated to generate negative pressure in the perforated pipe 1b, moisture such as ground water, etc., contained into the peripheral ground through a plurality of holes 11 is sucked and are discharged to the outside. According to the constitution, the chemicals grouted from the perforated pipe 1a by suction force is sucked at the same time, the chemicals are efficiently infiltrated, and a construction period can be reduced.