| 摘要 |
PROBLEM TO BE SOLVED: To provide a cut off structure using check valves for a back-fill filling hole of a soil resistant hydraulic structure such as a sealed segment, having improved working safety and workability during refilling of a back-fill material while improving the cut off performance of the check valve, allowing easy mounting/demounting thereof and improving the safety thereof, and to provide a back-fill material refilling method. SOLUTION: On the inside back-fill material filling side (the natural ground side) of a filling pipe 2, the simple check valve 20 is provided which is normally closed and opened with the filling pressure of the back-fill material. On the back-fill material filling side (the tunnel inside), the high-water cut off check valve 10 using a compression spring 13 is easily and detachably mounted via a snap ring 14, which is normally closed and opened with the filling pressure of the back-fill material. Such double cut off improves cut off performance and safety, resulting in improved working safety and workability during refilling the back-fill material. COPYRIGHT: (C)2009,JPO&INPIT |
