| 摘要 |
PROBLEM TO BE SOLVED: To provide excavation bits which are for use in cutting concrete or mortar reinforced with fibers, which can prevent cut fibers from having lengths longer than necessary, thereby able to prevent formation of a large mass of the concrete or mortar having the fibers adhering thereto when the concrete or mortar is removed. SOLUTION: The excavation bits (20N) are arranged on a shield cutter (100) of a shield machine. Each bit has a bit cutting section (30) located opposite to a bit mounting side (U) of the shield cutter (100), and the bit cutting section (30) has a notch region (40) formed in a surface thereof. The notch region (40) has a recessed cross section and extends along a bit rotating direction (direction indicated by an arrow T). COPYRIGHT: (C)2004,JPO&NCIPI |
