| 摘要 |
PURPOSE:To continuously obtain the accurate data of the horizontal displacement mode of an underground excavator from an execution scheme line in a real time, by laying one or more magnetic field generating cables to the surface of the earth and an appropriate magnetic field detection element is arranged in the side of the underground excavator to detect the magnetic field generated from each of said cables. CONSTITUTION:A current is supplied to the magnetic field generating cable 10 laid on the surface of the earth EP from an operation panel 30 while magnetic field detection elements S1, S2 are arranged to an underground excavator 20. The element S1 is fixed so that a magnetic field detecting direction is inclined by a predetermined angle from a vertical direction when looked from the front surface of the excavator 20 in the advance direction thereof and the element S2 is fixed so that a magnetic field detecting direction crosses the magnetic field detecting direction of the element S1 at an angle coming to line symmetry with respect to a vertical direction axis when looked from the front surface of the excavator 20 in the advance direction and both elements detect the magnetic field generated from the cable 10. The operation panel 30 compares the detected magnetic field levels by the elements S1, S2 to judge the horizontal displacement of the excavator 20 in the left and right direction with respect to the cable 10. |
