中文摘要：

在埋地金属管道检测领域中,常规检测手段多采取接触式的,检测前需要先对管道进行开挖或是停运,难以满足工业检测要求。而被动式弱磁检测技术可以实现对埋地管道的非开挖检测。本研究在介绍被动式弱磁检测技术原理的基础上,通过改变测磁传感器与管道垂直方向之间的距离来模拟管道的实际埋深,通过试验数据的分析可以得出磁场强度、管道埋深和腐蚀深度之间存在指数关系。在此基础上,结合磁场梯度变化和概率统计的原理可以得出缺陷判断的依据,即当磁场梯度在（μ-2σ,μ＋2σ）区间外变化时可判定为缺陷。与常规检测手段相比,被动式弱磁检测技术无需人为对管道进行磁化。在管道非开挖条件下,可以对埋地金属管道腐蚀状况进行科学评估,并实现二维成像。

英文摘要：

In the field of the buried metal pipeline detection,most of the conventional detection is a contact. It is necessary to excavate and stop running before detection. So it is difficult to meet the requirements of industrial detection. Passive micro magnetic detection technology can realize the buried pipeline trenchless detection. In the basis of the principle of the detecting technology,the distance between the magnetic sensor measurement and pipes is to simulate the actual depth of the pipe. It is found that the relationship between change of the magnetic intensity,the depth of pipeline,and corrosion depth which through the pipe after a lot of date of experiment are analyzed. On the basis of this,combination of gradient magnetic field and the principle of probability and statistics can draw defect judgment basis,that is when the magnetic field gradient in the interval（ μ- 2σ,μ ＋ 2σ）to change the defects can be judged. The conclusion shows,compared with conventional detection methods,the passive micro magnetic technique doesn＇t have to artificial magnetize the pipe in advance,which guarantees of buried metal pipeline corrosion condition of scientific assessment and realize the detection of 2D imaging in the condition of non-excavation.