| 摘要 |
PROBLEM TO BE SOLVED: To provide a non-circular excavating method for performing excavation having a regular polygon cross section without damaging the advantage of rotation motion. SOLUTION: In the method for excavating a hole (H) in the form of a regular N-angle of N vertical angles, an excavating means (T) formed in the form of a regular (N-1)-angle inscribed to the excavating regular N-angle is used, the excavating means (T) rotates at a prescribed rotating speed along the orbital circle (R) of a prescribed radius centering an excavating center (O), and rotates around an excavation means center (G) at a prescribed speed to excavate. However, the excavating means (T) in the form of the regular (N-1)-angle uses a blade-like excavation bit or jet. In addition, a regular (N+1)-angular excavating means (T) can be used. |
