【作者】 全红娟；

【导师】 李貅；

【作者基本信息】 长安大学 ， 地球探测与信息技术， 2003， 硕士

【摘要】 瞬变电磁法是一种时间域电磁测量方法，是利用不接地回线或接地线源向地下发送一次脉冲磁场，在一次脉冲磁场的间歇期间，采用不接地线圈接收感应二次磁场。该二次磁场是由地下地质体受到一次磁场激励后在其内部形成的感应涡流产生。随地质体导电性能及空间赋存位置的不同，感应涡流衰变的规律也有所不同，通过分析和研究二次磁场的时空变化特征，达到解决地质问题的目的，因而大大地简化了对地质目标体所产生异常的研究。 随着勘查精度要求的提高，对瞬变电磁法方法技术的研究也提出了新的课题。本论文根据瞬变电磁法勘探工作者的实践，利用电磁波运动学特征在讨论其基本原理和电磁波传播规律的基础上，结合在论文过程中进行的大量模拟实验资料，进一步引入了多孔径瞬变电磁发射场源，实验结果分析证明采用瞬变电磁多孔径发射场源改善了辐射场的方向性，提高了瞬变电磁法勘探的垂向分辨力。论文主要内容如下： 第一章 概述。文中简要介绍了瞬变电磁法的发展概况和基本原理，并提出了论文的主要研究内容和研究意义。 第二章 模拟实验研究。利用相似性准则进行大量的物理模拟实验，实验观测中以铜板和铜球作为目标体，详细介绍了模拟实验研究的目的、方案、使用设备以及实验内容，并对实验数据进行了处理分析，作出了不同模拟条件下单、多孔径的二次场衰减电压曲线和一次场等值线图，找出多孔径作发射源的探测最佳深度。 第三章，多孔径瞬变电磁实验分析。借助于相控阵原理的思想，结合模拟实验观测值对比结果，对多孔径TEM方法进行模型分析，详细讨论了多孔径一次场的辐射方向特性，利用光波的运动学特征提出类相干的概念，分析了多孔径TEM辐射源存在类相干现象，推导出类相干实验公式，并得出类相干项与多孔径框边长以及埋深的关系表达式和。 第四章 结论与建议。总结本论文的主要创新点以及其今后的工作，并讨论了此方法的不足之处。 多孔径TEM的解释理论和方法技术的应用，对提高TEM资料的解释精度及分辩能力无疑具有重要的意义。有关多孔径瞬变电磁技术还未见有关文献报道，因此通过模拟实验定性得出结论是本文的主要研究目的。如果实现瞬变电磁多孔径技术，即可配合多通道瞬变电磁法仪器，将多道数据采集技术和成像软件系统结合，将对瞬变电磁法这一勘探手段的实际应用注入新的活力，所研究的成果将对瞬变电磁法的应用和推广具有很大的实际意义。更多还原

【Abstract】 Being a method of time-domain electrical magnetic surveying, the transient electromagnetic method(TEM) can transmit first pulse electromagnetic field to underground making use of loop or electrical source and receive secondary induction field during of the pulse intermission. The rule of induction bow attenuation wave that is excited first field and formed in internal will be different with the difference of electric capability of geology body and existence position. So this method can resolve geology question and predigest consumedly research of geology object abnormity.With the improvement of precise demand new tasks will also appear for study of transient electromagnetic method. According to practice of transient electromagnetic operators, this paper will introduce a new multi-aperture transient electromagnetic method integrating a lot of simulation experiment data on the base of its primary theory and transmission rule. In the end, result shows this new method can improve so much direction of electromagnetic field that it increases lognitudinal resolving power. The main contents is as follows:The first chapter introduces summarization, it simply introduces the developed general situation and basic theory, it also brings forward main research contents and meanings in the future.The second chapter is about model experiment study, it introduces purpose, scheme, equipment and experiment contents having copperplate and copper ball as object by comparability rule experimenting plenty of physical models, deals with experiment data and makes second field attenuation voltage curves first field isoline both single aperture and mutli-aperture in different situation. In the end, it obtains best depth of multi-aperture source.The third chapter is experiment analyses of multi-aperture transient electromagnetic method, it analyzes multi-aperture transient method in theory and discusses radiation direction characteristic of first field by means phased array theoryand integrating result of experiment contrast. According to kinematics character it also brings forward similar interference concept and analyzes reason of similar interference phenomenon, it gained footing between similar interference item and depth on the base of it and experiment formula.The forth chapter is about conclusion and suggestion. It simply concludes innovation point of this paper, introducing work assume in the future and brings forward shortcoming of this experiment.It is important significance to apply this theory and technology to improve precise of TEM data and resolving power. The main purpose of this paper is obtaining conclusion by via of experiment, because it have not report about multi-aperture TEM technology so far. It can match multi- channels transient electromagnetic apparatus if this method comes true, further, connect data collection technology with imaging software system.In conclusion, it will immit new energy for exploration means of transient electromagnetic method, moreover its production will in practically have great significance to TEM applying and generalizing.更多还原