Estimating Possibility of Applying Magnetic Sensors in Advanced Probing System of Tunneling Shield

The possibilities of placing magneto-sensitive sensors on the hull of a tunneling shield were considered to implement the magnetometric part in the advanced sensing system designed to detect power cable lines and ferromagnetic objects on the tunneling operation line or in close proximity to it. The change in topology of the magnetic field produced by the current-carrying cable line and caused by the presence of massive ferromagnetic objects and cable shield was numerically studied. The dependencies were obtained for the magnitude of magnetic induction in the soil to the twisted-wire gradient of the three-phase power cable line and the possibility to detect this induction were determined. The theoretical possibility to determine the presence of ferromagnetic objects in the soil without artificial sources of electromagnetic fields was justified by the change in the magnetization characteristic of the tunneling shield hull in the geomagnetic field.