| 摘要 |
PROBLEM TO BE SOLVED: To provide a vertical hole excavation method and a vertical hole excavating device which achieve suppression of ground contamination dispersion while suppressing an increase in a construction period.SOLUTION: In the vertical hole excavation method of the present invention, a vertical hole 109 is formed by excavating a ground 101 having an upper water permeable layer 105 positioned on a water impermeable layer 103 and a lower water permeable layer 107 positioned below the water impermeable layer 103. This vertical hole excavation method comprises a first excavating step of excavating the vertical hole 109 up to a midway part 103a of the water impermeable layer 103, a replacing step of replacing soil excavated in the first excavating step with bentonite slurry 5, a layer formation step of forming a sealing layer 113 by spraying a layer formation material 111 onto an area S including a boundary part between the upper water permeable layer 105 and the water impermeable layer 103 in the bentonite slurry 5 and a second excavating step of excavating the vertical hole 109 up to the lower water permeable layer 107 from the midway part 103a of the water impermeable layer 103. |
