A Damage Risk Assessment Method for Crossing Pipelines Based on Non-Contact Magnetic Detection and Coercive Force

The crossing pipelines exhibit a relatively high potential risk due to environmental factors. Currently, limited by the confined inspection space and the thick anti-corrosion coating on the pipeline surface, there is no efficient and feasible method for detecting and assessing the damage risks of crossing pipelines. In this study, a strong-weak magnetic composite detection method is proposed to address the inspection challenges. Non-contact magnetic detection technology is utilized for preliminary screening, and the coercive force stress detection technology is employed for positioning and assessing the damage level. Firstly, a force-magnetic coupling magnetization model for steel pipelines is established, and the variation laws of the initial magnetization intensity and coercive force of ferromagnetic materials with the increase of stress under weak magnetic and alternating saturated excitation are studied. Subsequently, a strong-weak magnetic composite detection method and a grading assessment method for damage risks of crossing pipelines are established. Finally, engineering applications are carried out to demonstrate the feasibility and accuracy of this method. The results show that under weak magnetic excitation, the initial magnetization intensity of the pipeline increases with the rise of stress, while under alternating saturated excitation, the coercive force increases exponentially with the increase of stress. In practical applications, 11 damaged areas are identified, including 4 low-risk areas of Level III and 7 medium-risk areas of Level II. Through the structural deformation inspection of the suspension bridge tower and X-ray detection verification, consistent assessment results are confirmed. This proves the feasibility and engineering applicability of the strong-weak magnetic composite detection method, and provides a novel approach for the damage risk assessment of crossing pipelines.