| 摘要 |
<p>PROBLEM TO BE SOLVED: To provide an electromagnetic surveying method and electromagnetic surveying system by which the geological structure inside a tunnel and in the peripheral region of the tunnel is analysed by using the electromagnetic surveying principle in a time region. SOLUTION: An eddy current is produced in the measurement objective region by a transmitting loop cable that has been installed on the working face of a tunnel, and the current density distribution of the produced magnetic field is measured by a magnetic field sensor 22-1 installed inside the tunnel. In the same manner, the current density distribution is measured by a magnetic field sensor 22-2. Then, these measured results are temporarily stored in a memory 50, and the transient ratio data 52 being the hourly change ratio of the measured magnetic field are generated by an arithmetic processing part 44, and they are stored in the memory 50. Then, the transient ratio data 52 is compared by an analysing part 46 with the reference curve group data 72 previously stored in a data base 70. Then, by selecting a reference curve having the similar characteristic as the transient ratio data 52 from the respective reference curve group data 72 being the comparison object, the geologial structure in the measurement objective region is grasped.</p> |
