| 摘要 |
PURPOSE:To prevent the occurrence of unexcavated portion by a method in which an upwardly eccentric ring cuter is provided between paired drum cutters set on the horizontal rotary shaft, and rotation force from a rotary drive source is transmitted to the drum cutters and the ring cutter. CONSTITUTION:Rotation force of a rotary drive source 16 serves to turn a ring cutter 26 through a decelerating gear group 30, a horizontal rotary shaft 32, and a gear 34. By the rotation force of the drive source 16, drum cutters 22 are turned to the opposite direction of the ring cutter 26 through a decelerating gear group 38, a horizontal rotary shaft 40, gears 42 and 46, a horizontal rotary shaft 44, and gears 48 and 50. Since a rectangular pit is excavated under the ground by the excavator, an underground continuous wall having necessary strength can be formed without leaving unexcavating portion. |
