| 摘要 |
PROBLEM TO BE SOLVED: To prevent breakage of a packer due to friction of the packer with a boring hole and also prevent a chemical agent injected from a grouting rod from flowing back toward the ground surface. SOLUTION: A boring hole 40 is formed by a boring rod 1 equipped with a plurality of packers up to the upper end 41 of a specified chemical grouting zone L and a grouting rod is inserted in the inside of the boring rod 1, and built up to the upper end 41 of the chemical grouting zone L and a first stage 1s is excavated by the grouting rod 3, and the packer 10 is expanded to seala gap between the boring rod 1 and the surrounding natural ground G at the outside of the packer and seal a gap between the boring rod 1 and the grouting rod 3 at the inside of the packer. After a chemical agent is injected in the first station 1s, the packer 10 is contracted to form a gap between the inside of the packer and the grouting rod 3 and then a second stage 2n adjoining the first stage 1s is excavated by the grouting rod 3 and thereafter, the same procedure with the first stage is repeated.
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