| 摘要 |
<p>PROBLEM TO BE SOLVED: To reduce resistance at the time of excavation and control collapse of an inner wall after completion of the excavation. SOLUTION: A face plate provided with an excavation bit 28 for excavating a ground surface, a screw 15 for carrying out of an excavation pit soil excavated with the excavation bit 28 to the edge of which the face plate 16 is attached, and an outer cylinder 14 provided to surround the screw 15 are equipped. The edge of the outer cylinder 14 is positioned more forward than an excavation face formed by the face plate 16, and its outer circumferential face is made a tapered face 14b which is a gradually small diameter as it goes to the rear part.</p> |
