In order for preserving the subterranean stream which is cut off by the waterproof wall which is applied in case of the structure construction

摘要

PROBLEM TO BE SOLVED: To provide a water flow-through hole forming device and a water flow-through hole forming method for forming a water flow-through hole at an optional time in an impervious wall part to maintain underground water flow intercepted by a soil-mortar impervious wall. ;SOLUTION: In this water flow-through hole forming device 10, a pile core hollow steel pipe 20 closed at the upper and lower parts, with a pressure pipe 3a connected thereto is provided with a water flow-through hole 1 closed with an expansion bursting part 22, in a position of intercepting underground water flow by the driven pile core hollow steel pipe. The expansion bursting part 22 is constituted to block the water flow by fastening an elastic member such as a rubber plate to the pile core hollow steel pipe 20 with an elastic material fixing frame 23a by a screw 23b. A pile core material is built in the impervious wall to fill soil mortar, and in the hardening process of the soil mortar, a pressurized solution is filled in a pressure chamber from the pressure pipe. The expansion bursting part is thereby pushed outside of the pressure chamber to remove the soil mortar around and bursts at the expansion limit to open the water flow-through hole. Then a cut-off gate is pulled out of the ground to open a communicating hole, thus allowing the passage of water.;COPYRIGHT: (C)2003,JPO