【作者】 嵇艳鞠；

【导师】 林君；

【作者基本信息】 吉林大学 ， 地球探测与信息技术， 2004， 博士

【摘要】 随着社会经济和城市建设的发展，对工程与环境地质问题的关注，需要对浅层近地表进行精细探测与评价。瞬变电磁法勘察是环境与工程探测的重要方法，主要用于地下水调查、地下固体废物与污染物探测、考古、土壤评价及城市管线探测等。近年来，高分辨率探测浅层的地下目标体已经成为瞬变电磁法发展的热门方向，消除实测全程瞬变信号中的一次场和线圈过渡过程的影响，是实现浅层高分辨率探测的关键技术。本论文以非磁性导电球体在斜阶跃激励下的全程瞬变电磁响应为基础，以消除实测全程瞬变信号中接收线圈的过渡过程影响、提取全程瞬变二次场为研究重点，结合中国地质大调查项目“轻便面积性时间域电法仪器完善与示范”、国家自然科学基金项目“浅层高分辨率全程瞬变电磁(ATTEM)系统与关键技术研究”、国家自然科学基金项目“近区磁源阵列瞬变电磁探测系统与实验研究”和国家科技十五攻关计划子专题“强场源瞬变电磁技术完善与升级”的科研工作，主要研究成果如下：1.研究了斜阶跃脉冲激励下的一次感应电压及其过渡过程，并以非磁性导电球体为模型研究了斜阶跃脉冲激励下的二次感应电压和全程瞬变响应特征，分析了接收线圈的过渡过程存在时，一次场和二次场同全程瞬变响应的关系。2.研究了一次感应电压及其过渡过程对全程瞬变电磁响应的影响，分析了接收线圈的各个电性参数对全程瞬变响应的影响，论证了剔除一次场的过渡过程可以获取全程瞬变二次场，可以缩小最早取样时间，使探测深度变小。3.以实际测量参数和理论计算相结合的方法，对浙江舟山市老虎山4测线和吉林长春地质宫327室内实测瞬变响应进行全程二次场提取的研究，证<WP=150>明了剔除一次场的过渡过程可以提高浅层探测的分辨率和精度，消除了视电阻率值在浅部出现高阻盖层现象，进一步验证了勘探深度变小。4.研究了提高瞬变电磁信号晚期信噪比的方法，提出三点指数逼近非线性平滑滤波和基于几何平均的近似对数等间隔取样处理方法，基于“烟圈”理论的一维快速反演和解释的方法，研制开发了一套ATTEM数据处理及解释软件。5.利用自行研制的ATTEM样机在长春蔡家活断层和浙江舟山连岛工程的勘察应用，进一步验证剔除一次场可以提高浅层的探测分辨率。全文的主要创新性工作：1.首次研究了在考虑接收线圈的过渡过程情况下对实测全程瞬变电磁响应剔除一次场的方法，实现全程二次场的提取，以提高近地表浅层勘探的分辨率和精度。2.针于自行研制的ATTEM系统的均匀密集采样方式，首次提出三点指数逼近非线性平滑滤波和近似对数等间隔取样处理的方法，以提高瞬变信号的晚期信噪比。3.从解释方法和测量系统上，突破了常规时间域电磁系统只测量衰减段瞬变响应及相应的解释方法，自行研制的ATTEM样机实现了全程瞬变响应的测量，并研制开发了可以剔除一次场影响的处理解释软件，在长春蔡家活断层和浙江舟山连岛工程勘察应用中，对提取全程二次场算法进行了验证。围绕“浅层高分辨率全程瞬变电磁系统中提取全程瞬变二次场的技术研究”有待进一步研究的工作：1.针对浅层高分辨率瞬变电磁探测问题，需要研究接收线圈的频率特性，缩短接收线圈的过渡过程，降低全程瞬变信号早期畸变。2.进一步研究在早期全程瞬变信号的超高速采样技术、高精度实时同步技术，提高记录数据的分辨率。3.结合时频分析、短时傅里叶变换、小波变换等技术，研究晚期瞬变信号的压制噪声技术，提高测量信号晚期信噪比，使数据可用范围加大。4.进一步研究多匝小线圈工作装置下的反演及解释工作。5.研究瞬变电磁信号偏移成像技术，目前国内研究的不够。更多还原

【Abstract】 With the developing of social economic and city construction, and more attention for the engineering and environmental geology, shallow subsurface investigation and evaluation has become the key subject of current research. Transient electromagnetic exploration (TEM) is an important method for environment and engineering, mainly applied in ground water investigation, ground solid waste and poison detecting, archaeology, soil engineering studies and detecting city ground piping, etc.Recently, high resolution shallow subsurface sounding is a popular electromagnetic research orient. Removing primary field and transient process from the measured all-time TEM(ATTEM)signals is the key technology for high resolution shallow subsurface sounding. Based on all-time transient electromagnetic response of nonmagnetic conductive sphere under tilting step signal, this dissertation, which depends on China Geology Investigation Project ”Portable area TEM instrument advancement and demonstration” and National Natural Science Foundation ”Research on high resolution shallow subsurface all time TEM system and key technology” and “Research on near area magnetic source TEM system and experiment ” and National Science and Technology the tenth Five Plan ”Strong field source TEM technology perfecting and advancement”, mainly discusses on removing transient process from the <WP=152>measured all-time TEM signals and gaining the secondary field. The achievements are obtained as following:1. Research on primary induction voltage and its transient process under the tilting step impulse, and discuss all time transient response characterization of secondary induction voltage and its transient process based on nonmagnetic conductive sphere model. Analyze the all time transient response relation between the primary field and secondary field while the transient process exists in receiver coil.2.Research all time transient electromagnetic response affected by primary induction voltage and its transient process, and analyze all time transient response changing with the receive coil electrical parameters, also demonstrate to gain all time secondary field by removing primary field and reduce earliest sampling time in order to achieve smaller exploration depth.3. According to combine measured parameters and theoretical computation, research on all time secondary field extraction at line 4 Mountain Tiger Zhoushan Zhejiang Province and Changchun Geology Palace room 327, and prove further that removing the primary field can improve the resolution and precision of shallow subsurface sounding and it can eliminate high resistivity shallow layer during apparent resistivity reversion.4. It is put forward to adopt three-point exponential approximation nonlinear smooth filter and logarithm equal-interval based on geometry average approximation after researching on improving later signal noise ratio of transient electromagnetic signal. Develop a set of software for data process and inversion based on “smoke coil” theory one dimensional fast inversion method.5. The exploration results, using self-made ATTEM instrument Changchun Caijia alive faultage and zhoushan Liandao Engineering Zhejiang Province, prove further that removing primary field can improve resolution of shallow subsurface sounding. Main innovation in this dissertation:1.It is proposed firstly removing primary field from measured all time transient electromagnetic response while considering transient process of receiver coil and extract all time secondary field and improve resolution and precision of shallow subsurface exploration.2.To the end of equally compression sampling, it is put forward firstly to process data using three-point exponential approximation nonlinear smooth filter and logarithm equal-interval in order to enhance later signal noise ratio of <WP=153>transient electromagnetic signal. 3. From the point of inversion method and measurement system, break through only measuring attenuation part of transient response in the routine time-domain electromagnetic更多还原