| 摘要 |
PROBLEM TO BE SOLVED: To ensure the confirmation of the position of a paved manhole before subsequent processes are performed. SOLUTION: Distances are premeasured from the center of a manhole to three roadside reference points. The manhole opening is closed with a temporary cover 3 marked in the center, and the road including the temporary cover is paved uniformly. After the paving, a manhole center is determined from the reference points, and the pavement in the center is cut away by a core drill to expose the center of the temporary cover 3 so that the center is confirmed. A center fixing device 5 holed in the bottom is placed in the center, and the center is reconfirmed before a start of cutting. A shaft of a cylindrical cutter is set on the center fixing device to cut a circle around the manhole, and a manhole cover receiving frame is installed. COPYRIGHT: (C)2004,JPO
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