| 摘要 |
PROBLEM TO BE SOLVED: To provide the control method of a manhole, by which the buried manhole can be specified accurately, and a manhole cover particularly suited to the control method. SOLUTION: Control numbers, corresponding to each record of a control file, are marked to the surface of the manhole cover before installation, and the manhole cover, on which the control number of interest is marked, is mounted on a manhole frame buried at the place of burying stored in the control file in response to the control number of interest. The manhole covers have characteristic control numbers for each manhole cover marked on the surfaces after casting. The control numbers can be given by fixing control plates, to which the control numbers are marked or projected, into shallow recesses molded to the surfaces of the manhole covers by casting.
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