| 摘要 |
<p>PURPOSE:To prevent any unexcavated remnants in an oval sectional tunnel from occurring by forming a section of an excavator into an ellipse, while installing a sliding cutter, being free of slide motion, in a fixed cutter installed radially in an excavating plate, and clamping each bit group to both these cutters. CONSTITUTION:A section of a shield excavator body 1 is formed into an ellipse, and an excavating plate is set up in front of this body 1. In addition, a fixed cutter 2 is radially installed in this excavating plate, and a group of bits 21 is installed in this cutter 2. Then, a sliding cutter 3 is installed in the cutter 2 free of slide motion, and a group of bits 31 is installed in this cutter 3, while a difference in length between an oval major axis and a short axis is set as an expansion stroke of the sliding cutter 3.</p> |
