Study on detection range of short distance water‐bearing anomaly via train‐borne transient electromagnetic method under interference of train tracks

The proportion of groundwater-related diseases in the operational high-speed railway tunnels in China is increasing and rapid and accurate disease monitoring is urgently needed. Therefore, it is a new attempt to monitor 5- to 10-m water-bearing anomalies in operating tunnel structures by using train-borne transient electromagnetic method. The stationary interference source train tracks in the tunnel environment have serious electromagnetic interference to the monitoring of water-bearing anomalies. Thus, this paper combines numerical simulations and indoor experiments to carry out research on the minimum water-bearing anomalies that can be monitored at such close distances by train-borne transient electromagnetic method under electromagnetic interference from train tracks. First, a comparative study of the electromagnetic characteristics of the water-bearing anomalies when their own parameters change is carried out by numerical simulation, followed by a comparative analysis of the electromagnetic response of the water-bearing anomalies under the interference of train tracks. For the missing electromagnetic response of the coil-metal-anomaly in the numerical simulation, a full-scale physical model experiment is conducted to obtain the time range of the three interferences. Also in the experiments, the feasibility of existing instruments for close range water-bearing anomalies detection is verified by comparing different transient electromagnetic instruments. Finally, the minimum water-bearing anomalies that can be monitored in close proximity under the interference of train tracks are obtained experimentally.