To collect a propelling machine from a starting shaft as it is without disassembling and re-assembling the same, even if an arrival shaft cannot be bored.
The propelling machine 1 excavates the natural ground by extending a cutter 4 in a radially outer direction to carry out rotational driving, and at the same time the machine 1 is propelled together with propelling pipes A by a propelling jack arranged at a starting end of the propelling pipes, via a cutting-edge ring 3 attached to the front end of the top propelling pipe A. When the front end of the propelling machine reaches an existing structure, a natural ground retaining material 20 is injected into an overbreak portion by a natural ground retaining material injecting means 6, and a cutoff packing 7 is inflated to make contact with an inner peripheral surface of the propelling pipe. Further, engagement of the cutting-edge ring 3 with a drum 2 is canceled to retreat the cutter 4 in a radially inner direction, followed by penetrating the propelling pipes into the existing structure. Thereafter the cutoff packing is deflated and the propelling machine is retreated rearward along the interior of the propelling pipes to be collected.
KUNUGIBARA NOBORU
HAYASHI YUUGO
Tadashi Takahashi
Takashi Watanabe
Masakazu Aoyama