【作者】 张宇；

【导师】 胡杰；

【作者基本信息】 太原理工大学 ， 电子科学与技术， 2023， 硕士

【摘要】 瞬变电磁法是一种盲区小、深层探测分辨率较高的磁法地球物理勘探技术,其对陷落柱、含盐充水体、导电矿物等低阻构造区域有着较好的辨识能力,因此成为了煤矿水害防治中的一种常见探测手段。尽管瞬变电磁技术在探水方面的应用已有数十载,但由于国内外采矿方式差异较大,同时在先进技术及装备设计上受到垄断,该技术的应用与推广依旧受到制约,装备设计方面仍有较大的提升空间。本文以瞬变电磁接收机的设计作为主轴,从便携性作为出发点展开研究工作。文章首先在第二章介绍并分析了瞬变电磁的工作原理,利用多物理场仿真工具COMSOL对瞬变电磁响应的时域全过程和频域特征进行了研究,并在第三章进行器件对比与选型的同时,对电路中模拟噪声的来源及传递路径进行了详细的介绍与分析,然后给出了基于所选器件的高增益（60 d B）、低输出噪声(1.16 m V_RMS)、高线性度的模拟信号处理电路参考设计,以及详细的多通道ADC选型规则和电路、配套的数字控制电路、多轨道电源电路、电池管理电路的参考设计,完成了接收系统样机的研制。对于传统接收线圈体型较大且沉重的问题,本文分析了线圈直接耦合与中心抽头耦合的差异,然后提出了一种基于PCB、一致性高、平面面积仅为10×10 cm²、单层有效面积可达0.433 m²的平面线圈设计,使瞬变电磁接收系统的便携性得到了提升。为了改善瞬变电磁接收机的兼容性,实现非同步式的瞬变电磁信号采集,本文在第四章提出了基于STA/LTA算法的瞬变电磁脉冲信号实时识别与采集方法。文章结合瞬变电磁响应实测数据对STA/LTA算法的时窗选择进行了详细说明,并分析了均匀分布随机噪声、高斯白噪声、正弦噪声对该方法的影响,为检测阈值的选取提供了指导。最后,作者等人在校区中心草坪与河道附近对所设计的瞬变电磁接收系统进行了验证性试验,测试结果证明了该接收系统的有效性。更多还原

【Abstract】 Transient electromagnetic method is a magnetic geophysical exploration technology with small blind spots and high deep detection resolution.It has good identification capabilities for low-resistance structural areas such as collapse columns,saltwater-filled bodies,and conductive minerals.Therefore,it has become a common detection method in the prevention and control of coal mine water hazards.Although the application of transient electromagnetic technology in water exploration has been around for decades,due to the large differences in mining methods at home and abroad,and the monopoly on advanced technology and equipment design,the application and promotion of this technology is still restricted,and there is still a lot of room for improvement in equipment design.This paper takes the design of the transient electromagnetic receiver as the main axis and starts work from the portability.The article first introduces and analyzes the working principle of transient electromagnetics in Chapter 2,uses the multi-physics field simulation tool COMSOL to study the time-domain whole process and frequency-domain characteristics of transient electromagnetic response,and while comparing and selecting devices in Chapter 3,it also introduces and analyzes the sources and transmission paths of analog noise in the circuit in detail.Then it gives a reference design for an analog signal processing circuit with high gain（60 d B）,low output noise(1.16 m V_RMS),and high linearity based on the selected devices,as well as detailed multi-channel ADC selection rules and circuitry,supporting digital control circuitry,multi-track power circuitry,battery management circuitry reference design,completing the development of the receiver system prototype.For the problem that traditional receiving coils are large and heavy in size,this paper analyzes the difference between direct coupling of coils and center tap coupling,and then proposes a flat coil design based on PCB with high consistency,a flat area of only 10×10 cm²,and a single-layer effective area of up to0.433 m²,which improves the portability of transient electromagnetic receiving systems.In order to improve the compatibility of transient electromagnetic receivers and achieve asynchronous transient electromagnetic signal acquisition,this article proposes a real-time identification and acquisition method for transient electromagnetic pulse signals based on STA/LTA algorithm in Chapter 4.The article combines transient electromagnetic response measurement data to explain in detail the selection of STA/LTA algorithm window,and analyzes the impact of uniform distribution random noise,Gaussian white noise,sinusoidal noise on this method to provide guidance for selecting detection thresholds.Finally,the authors conducted verification tests on the designed transient electromagnetic receiving system near the central lawn and river channel in the campus.The test results proved the effectiveness of this receiving system.更多还原