JACKING METHOD BY UNDERWATER ARRIVAL

PROBLEM TO BE SOLVED: To provide a jacking method in which a guiding machine therefor can be easily recovered even in an underwater part, thereby dispensing the construction of an arrival shaft and reducing construction cost.SOLUTION: Water cut-off between a casing 4 and natural ground G is carried out by a portal cut-off part 20 on a start side, and then a guiding machine 10 is propelled. The guiding machine 10 is made to arrive in an underwater part W, and thereafter a pinch valve 14 is closed, an opening inside the casing 4 is blocked by a water cut-off member 30 inside the casing, the guiding machine 10 is disconnected from the casing 4 in the water, and an opening of a front end 4a of the casing 4 from which the guiding machine 10 is disconnected is closed by a cut-off cover.