| 摘要 |
<P>PROBLEM TO BE SOLVED: To inexpensively manage a position in installation of a caisson. <P>SOLUTION: Laser surveying machines 40 and 42, which apply two laser beams 50 and 52 at different heights on a normal line 34, respectively, are disposed in an existing caisson 14, and two laser targets 70 and 72 at a distance in the direction of the normal line 34 are disposed in an installation caisson 18. The entrance/exit and installation height of the installation caisson 18 with respect to the normal line 34 can be checked by positions of the laser beams 50 and 52 launched into the laser targets 70 and 72. <P>COPYRIGHT: (C)2012,JPO&INPIT |
