| 摘要 |
PROBLEM TO BE SOLVED: To provide a water swivel which can adapt to not only a normal and reverse circulation system for a construction method for a cast-in-place pile but also excavation by a reverse circulation system using an air lift system, at a greater depth. SOLUTION: An air introducing port 30 is provided in an outer housing 16 which constitutes a main body of the water swivel 10 for supplying water into an excavated pile hole, and an air passage 24 is formed in the wall thickness of an inner housing 17 serving as a rotating cylinder. An air supply pipe 35 is pulled out from the air passage 24 so as to be pointed to a pile for an air lift, which is positioned along a rod 20. Line packing 25 and line packing 26 are provided between the outer housing 16 and the inner housing 17 on a rotational side so that outside air can be prevented from being mixed in from a slight gap between the inner and outer housings, and the water swivel can adapt, in a stationary state, to the squeeze pumping or suction of slurry into an excavated hole through the rotating rod. COPYRIGHT: (C)2005,JPO&NCIPI
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