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.