| 摘要 |
PROBLEM TO BE SOLVED: To provide a construction method for a manhole for reducing a cost, shortening a construction period and minimizing a diameter of a cylindrical casing at the same time, and for reducing an amount of concrete when a cut-off concrete, a backing concrete or the like is placed. SOLUTION: In a process for hoisting down the lowest stage, after cut parts 23, and a front end part of an inflow pipe 17 and the front end part of an outflow pipe 18, are fitted, a part of the manhole 22 is hoisted down to a bottom surface of a vertical shaft 13 while the end parts of the pipes 17, 18 are inserted into the cut parts 23. As a result, the cylindrical casing 12 is minimized, the cost is reduced, and the period of construction is shortened. Further, the amount of use of the concrete is reduced when the backing concrete 29 is placed in a gap d2 between the cylindrical casing 12 and an assembling type manhole 20, and when the cut-off concrete 14 or the like is placed. COPYRIGHT: (C)2004,JPO
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