SHEATH PIPE JACKING CONSTRUCTION METHOD

PROBLEM TO BE SOLVED: To easily and newly block a sheath pipe at an arrival shaft side end after a new pipe arrives. SOLUTION: In this construction method, a buoyancy material a is poured into the sheath pipe 1 to perform pipe jacking while letting the new pipe 2 float by buoyancy. A jig 20 for blocking the other end is provided at the other end of the sheath pipe 1, the most leading new pipe 2 is fitted and supported into a cylindrical body 122 of the jig 20 in a watertight manner, and then a lid (a level adjusting member) 123 is removed from the cylindrical body. Since the new pipe reaches the arrival shaft side end of the sheath pipe and its tip is fitted into the cylindrical body to block an end of the sheath pipe by itself, the lid blocking the sheath pipe thus far can be removed, and the new pipe protrudes further from the sheath pipe if its blocking condition allows travel of the new pipe. At this time, centering is performed by fitting a tip of the new pipe into the jig. The buoyancy material in the sheath pipe overflows from a hole 126 of the lid to maintain a level of the buoyancy material in the sheath pipe constant. COPYRIGHT: (C)2006,JPO&NCIPI