| 摘要 |
PURPOSE:To measure the horizontal displacement quantity of an underground excavator from an execution scheme line in a real time without accompanying traffic blocking, by calculating the horizontal displacement quantity on the basis of the detection value of a magnetic field detection element and the depth of the detection element from a magnetic field generating cable. CONSTITUTION:An underground excavator 1 starts excavation from a departure pit 2 while a guide line 4 is laid on the surface of the earth along an execution scheme line and a constant current with low frequency is supplied from an AC constant current source 5. Coils 11-13 and an inclination gauge 14 are arranged to the excavator 1 and the outputs thereof are respectively transmitted to an arithmetic unit 7 through a signal transmission line 6. The arithmetic unit 7 calculates V2/V1 from induced electromotive voltage levels V1, V2 respectively detected by the coils 11, 12 and calculates a depth (d) from a predetermined formula on the basis of an inclination gauge 14. Further, on the basis of the angle of rotation of the coil 13 when the output of the inclination gauge 14 and that of the coil 13 become min., the depths of the respective coils 11, 12 and the distance between the coils 11, 12 are corrected according to a predetermined formula and the corrected values are substituted for the other predetermined formula to calculate the horizontal displacement quantity of the excavator 1. |
