| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To facilitate extraction of a concrete core having a large diameter to some extent and a height smaller than the diameter. <P>SOLUTION: First core-extraction cutting having a locus S1 and second core-extraction cutting having a locus S2 whose loci are circumscribed by each other, are performed on a concrete member C by use of a first core cutter (1) and a second core cutter (2). A second core C2 surrounded by the second core-extraction cutting locus S2 is removed. Thereafter, a plurality of perforations (h) are made in the outer circumference of the first core C1 partially exposed to a circular hole (H) surrounded by the first core-extraction cutting locus S1 from the bottom of the circular hole (H) formed by removing the second core C2. The bottom of the first core C1 exposed to the circular hole (H) is cut to extract the concrete core C1. <P>COPYRIGHT: (C)2012,JPO&INPIT</p> |
