Figure: On-board transient electromagnetic drag measurement

Figure: Inversion results of on-board transient electromagnetic drag measurement

In order to test the effect of vehicle-mounted transient electromagnetic drag measurement, the measurement was carried out at the middle line of the South to North Water Diversion Project in the Henan section. The measurement lines passed through four metal drainage pipes and one inverted siphon respectively. The measurement speed of vehicular transient electromagnetic drag in the field is about 5 km/h. The data collected in the field are inverted, and the results are shown in Figure 2. In Figure 2, the positions of low resistance anomalies A, B, C and D correspond to the positions of metal drainage pipes respectively. At the horizontal position of about 240 meters, there is a low resistance anomaly area, which is very consistent with the site inverted siphon position, and the depth is about 10-15 meters. It shows that the vehicle-mounted transient electromagnetic drag measurement has a good effect.