| 摘要 |
PROBLEM TO BE SOLVED: To provide a rectangular cross section boring machine capable of efficiently burying a tubular support member of elongated rectangular cross section into the ground. SOLUTION: The greater part of the ground excluding small parts at four corners of rectangular cross section can be excavated because of excavating the ground using a lateral pair of screw shafts partially overlapped with each other from the front view in a jacking direction and rotated in opposite directions to each other. Further, since sediment produced by excavating the ground is discharged by a lateral pair of screw blades in linkage, obstacles such as gravel and rocks buried in the ground can be positively conveyed backward, thereby causing no clogging. COPYRIGHT: (C)2007,JPO&INPIT |
