| 摘要 |
PROBLEM TO BE SOLVED: To provide a ground improvement method by using a special multiple pipe which can greatly reduce steps of work in soil improvement work and increase workability by making it possible to establish a columnar soil improvement body in the ground and perform soil improvement by one working process.SOLUTION: In a ground improvement method by using a special multiple pipe, a special multiple pipe 1 comprises a cylindrical screw pipe 5 moved upwards and downwards inside a casing pipe 2, and a spiral screw blade 10 for soil removal is attached to the outer periphery of the screw pipe 5 while a plurality of open holes 11 penetrating in the vertical direction are installed in the screw blade 10 from bottom to top. In the method, after the special multiple pipe 1 is penetrated, an improvement material or a soil purification material is jetted into the special multiple pipe at the bottom edge of the special multiple pipe 1, while the casing pipe 2 and the screw pipe 5 are rotated so that the jetted improvement material or soil purification material is moved in the vertical direction by the open holes 11 installed in the screw blade 10 and is mixed with an original ground soil in the special multiple pipe 1.SELECTED DRAWING: Figure 1 |
