基于磁异常的平行管线数值模拟

摘要

In order to detect underground parallel pipeline accurately and efficiently,the authors used the magnetic dipole method to simulate underground parallel iron pipeline model,chose MATLAB to calculate the magnetic anomaly curve generated by the model,and analyzed changes of the magnetic anomaly curve caused mainly by the basic shape and the number of peaks.Numerical simulation re-sults show that the amplitude and magnetic width of magnetic anomaly signal are both affected by the selected parameters.Specifically, the center distance,depth and susceptibility all significantly change the basic curve shape as well as the number of curve peaks;the length,diameter and thickness affect the amplitude,but do not change the basic shape;with the same parameters,the calculated magnet-ic anomaly curves respectively from the COMSOL software and the magnetic dipole method have the same normalization shape,which shows that the demagnetization affects the curve amplitude of magnetic anomaly,thus proving the validity of magnetic dipole method in the parallel pipeline model forward analysis.%为了准确、高效探测地下管线,利用磁偶极子分析法模拟水平平行铁质管线模型,应用Matlab软件计算该模型产生的磁异常曲线,分析模型在不同参数变化下磁异常曲线的基本形态、峰值个数变化及原因.数值模拟结果表明,所选取参数对磁异常信号的幅值和磁宽均有影响:管间距离、埋深和磁化率明显改变了曲线的基本形态,影响曲线峰值个数;管线长度、外径和管壁厚度影响曲线幅值,不改变其基本形态;在相同参数条件下,分别应用Com-sol软件与磁偶极子分析法计算磁异常曲线,结果归一化后对比发现曲线形状吻合,验证退磁效应影响磁异常曲线幅值,从而验证了磁偶极子分析法应用于平行管线模型正演分析的正确性.