| 摘要 |
PROBLEM TO BE SOLVED: To solve the problem that an excavated hole with a strong wall cannot be formed in a specific earth condition because earth and sand fall from the wall of the excavated hole before a filling material is filled in the completed excavated hole. SOLUTION: An earth removal head 40 is removably attached on the bottom end of a drill rod 20. By this, the earth in the circumference is removed when the head is made to penetrate the earth. Upon the arrival at a specified depth, the drill rod 20 is removed from the earth removal head 40. The bottom end of the rod 20 is designed as an earth removal part 30 with a width wider than that of the drill rod part adjacent to it. Because the earth removal part 30 has a wider width, the earth and sand falling from above at the time of extraction is removed toward the wall of the excavated hole. COPYRIGHT: (C)2005,JPO&NCIPI
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