After jacking method and the fitting structural null takeoff pit which

摘要

PROBLEM TO BE SOLVED: To allow work for a connection of an inner pipe at the outside of an outer pipe even after connecting the inner pipe. ;SOLUTION: In this propulsion technique, the outer pipe 1 of a double pipe P having the inner pipe 2 movably mounted in the outer pipe 1 via a filler layer a is pressed into a ground W of a starting shaft S, the end face of an outer pipe 1 of a following double pipe P to be pressed therein is put in contact with the end face of the outer pipe 1 of the preceding double pipe P, a spigot 2b of the following inner pipe 2 is inserted and connected into a socket 2a of the preceding inner pipe 2, and the preceding and following double pipes are joined together. Then, horizontal thrust is applied to the rear end face of the outer pipe 1 for propulsion, and the joint and propulsion are alternately repeated for integral entrainment of the outer pipe being moved and the inner pipe being kept in the inserted and connected condition in the lateral direction. A propulsive force transmitting segment 8 is laid between the end faces of the outer pipes of the preceding and following double pipes P, P, via which propulsive force is transmitted from the following double pipe P to the preceding double pipe P. After work for the connections of the inner pipes 2, 2, a centering ring 10 and the segment 8 are fitted thereto and a cover 11 is applied thereon for propulsion.;COPYRIGHT: (C)2003,JPO