含腐蚀缺陷管道弱磁信号的正演模型

A Forward Modeling of Weak Magnetic Signal in Defective Pipeline

针对埋地集输管道在非开挖条件下的腐蚀检测难题,结合磁偶极子模型以及应力磁化强度模型,建立一种含缺陷管道弱磁信号正演模型。通过数值模拟方法研究了腐蚀缺陷磁感应强度波形特征及离地高度、磁化强度对磁感应强度的影响。结果表明:腐蚀缺陷处Bx和By出现极值特征且方向相反,Bz出现过零点特征且峰值改变方向;分别讨论了离地高度以及磁化强度对信号的影响。通过开展现场检测,验证正演模型的准确率,其误差率为11.11%。

Aiming at the problem of corrosion detection of buried gathering and transmission pipeline under trenchless conditions,combined with magnetic dipole model and stress magnetization model,a forward modeling model of weak magnetic signal of defective pipeline was established.The waveform characteristics of magnetic induction intensity of corrosion defects and the effects of ground clearance and magnetization on magnetic induction intensity were studied by numerical simulation.The results show that at the corrosion defect BX and by had extreme value characteristics and opposite direction,BZ had zero crossing characteristics and the peak value changed direction.The effects of ground clearance and magnetization on the signal were discussed respectively.Finally,the field test was carried out to verify the accuracy of the forward model,and the error rate was 11.11%.