Research on Anchor Cable Force Detection Technology Based on Magnetic Intensity Distribution of Permanent Magnet

The anchor cables of slopes are affected by long-term environmental corrosion, geotechnical creep, and adverse weather, resulting in gradual loss of tensile force, leading to structural failure and subsequent safety accidents. This paper conducts research based on the distribution characteristics of magnetic induction intensity of permanent magnets, including model derivation, theoretical simulation, and indoor experiments, aiming to propose a new anchor cable force monitoring technology with high sensitivity, strong applicability, and good stability. Based on the molecular circulation model and the Biot-Savart law, the analytical expression of the spatial magnetic field distribution of a rectangular permanent magnet is derived, and combined with the stress-strain relationship characteristics of anchor cables, a theoretical model for the relationship between anchor cable tensile force and magnetic induction intensity is established. MATLAB was used to simulate and analyze the spatial magnetic field distribution and force-magnetic relationship. The analysis shows that the magnetic induction intensity along the central axis of the permanent magnet approximately exhibits a symmetrical quadratic curve distribution; its value is significantly negatively correlated with the anchor cable force. Based on this, a new anchor cable force monitoring technology is proposed, and an indoor experimental platform is established. Indoor experimental studies further confirmed the negative correlation between force and magnetism. The fitting results of the force-magnetic curve show that a quadratic function can better describe the correspondence between magnetic induction intensity and anchor cable force. Reproducibility analysis of experimental data showed low dispersion in magnetic induction values under various design loads and good stability, validating the effectiveness and applicability of the proposed anchor cable force monitoring technology.