孔中磁法位场延拓在城市深埋金属管线精细探测中的应用研究

Research on Application of Potential Field Continuation of the Borehole Magnetic Survey in Detailed Detection of Deep Buried Metal Pipeline in Urban Areas

在城市发展与改造过程中,地下深埋管线的精细探测问题严重影响着工程的施工安全。现阶段通常选用孔中磁法等物探方法对深埋金属管线进行精细探测。针对常规孔中磁法仅能判断管线埋深、无法获取管线平面位置的缺陷,本文尝试将孔中磁测数据进行位场延拓,从而获取管线的平面位置信息。首先通过将钻孔中采集到的原始磁测异常曲线进行数据扩边、傅里叶变换、位场延拓、反傅里叶变换等一系列数据处理过程,从而获得不同延拓距离后的磁测异常曲线,然后根据延拓后的磁测异常曲线上的“尖脉冲”标志,获得地下深埋金属管道的平面位置信息,同时对管道埋深判断也更加精细。最后借助于模拟实验和天津滨海新区雨污分流改造项目,将孔中磁法位场延拓方法应用于地下深埋燃气管道的精细探测中。结果表明:孔中磁法位场延拓不仅可以更精细地判断管道埋深,还可以获得管道的平面位置信息。

The problem of detailed detection of deep buried metal pipeline seriously affects the construction safety of the project in the process of urban development and reconstruction.At present,some geophysical prospecting methods such as borehole magnetic method are usually used for detailed detection of deep buried pipeline.In view of the defect that the conventional borehole magnetic method can only distinguish the buried depth of the pipeline without obtaining the plane position of the pipeline,this paper attempts to extend the potential field of the borehole magnetic data to obtain the plane position information.And this method is fast in operation and stable in effect.In this paper,the original magnetic anomaly curves collected from boreholes are subjected to a series of data processing processes,such as data expansion,Fourier transform,potential field extension,inverse Fourier transform,etc.,so as to obtain the magnetic anomaly curve of different continuation distance.Then,according to the‘sharp pulse’mark on the extended magnetic anomaly curve,the plane position of the buried metal pipeline is obtained,and its depth is judged more finely.Finally,with the help of the simulation experiment and the application of detailed detection of underground deep buried gas pipeline in the diversion reconstruction project of rain and sewage pipeline in Binhai new district of Tianjin province,the results show that the potential field extension of borehole magnetic can not only judge the depth of the deep buried pipeline more accurately,but also obtain the plane position of the pipeline.