| 摘要 |
PURPOSE:To raise the efficiency of operations by a method in which casings fitted with drill shafts are connected with each other so that the opening diameter of an excavating blade coincide with that of an adjacent blade, and a steel sheet pile is attached to the front face of the casing connection. CONSTITUTION:A motor 15 is actuated to turn drill shafts 7 in casings 8, and three pits are excavated by excavating blades 9 and expanded by excavating blades 11 to form a sidelong continuous pit. The casing connection 22 carrying a wide steel sheet pile P is penetrated into the continuous pit, the drill shafts 7 are reversely turned, and the excavating blades 11 are closed. A cylinder 20 for vertical driving is driven, a support frame 19 and the connection 22 are pushed down, and the steel sheet pile P is set. A chuck-opening and closing cylinder 27 is driven to open claws 25, and the connection 22 and the shafts 7 are pulled up together with a driver 4.
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