| 摘要 |
PURPOSE:To easily penetrate a cut-off sheet, by a method wherein a lower part is pre-excavated through rotation in the unfolded state of an unfolding head located to the tip of a rotary head, and a draw-in force is exerted on the lower end part of the cut-off sheet through a casing inserted outwardly of the rod. CONSTITUTION:A cut-off sheet 10 is penetrated as the lower part of about the whole of the width of the cut-off sheet 10 is pre-excavated with a rotary rod 2 forward rotated and an excavating blade 4 of an excavating head 3 brought into an unfolded state. When the excavating head 3 is lowered down to a specified depth Z, penetration is stopped, and with the rod 2 reversed, the excavating head 3 is brought into a folded state. The excavating head 3 is inserted into the casing 5 through expansion of a cylinder device 7 as a wire 14, by means of which a driving part 1 is lifted, is hoisted, and the wire 14 is loosened to exert the weight of a whole device on the lower end part of the cut-off sheet 10 to draw in the cut-off sheet 10 to the specified depth Z. |
