Research Article
Characteristic of Magnetic Fluctuation of Underground Passing Pig Labeled with Magnets
Table 1
The influence of each parameter on the magnetic anomaly.
| Model parameters | Range | With the increase in the parameter |
| Pipeline buried depth (mm) | 2-3.5 | Fluctuation decreases | Existence of permanent magnets | Nonexistent-existent | Obvious fluctuation | Pipeline outer diameter (mm) | 500-700 | Fluctuation decreases | Pipeline wall thickness (mm) | 4-10 | Fluctuation decreases | Pipeline length (m) | 60-75 | Fluctuation almost remains the same | Pipeline permeability | 100-900 | Fluctuation decreases | Number of permanent magnets | 2-6 | Fluctuation increases at the center of the measuring line and almost unchanged at both ends | Polarity of permanent magnets | Horizontal-vertical | Fluctuation is negligible | Magnetic intensity (nT) | 21000-69000 | Fluctuation almost remains the same | Magnetic dip | −80°~80° | Fluctuation decreases first and then increases | Magnetic declination | −25°~25° | Fluctuation almost remains the same | Detection height in the experiment | 0.5 m-1.2 m | Fluctuation decreases |
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