隧道全空间瞬变电磁效应一维反演研究

发布时间：2018-05-16 14:05

本文选题：瞬变电磁法 + 一维半空间　；参考：《西南交通大学》2014年硕士论文

【摘要】：瞬变电磁法是对富水不良地质体进行超前地质探测的新方法。瞬变电磁法具有对低阻地质体响应敏感的特征,因此对充泥充水溶洞、充水断层、充泥充水破碎带等低阻特性的地质体的预报优势明显。目前基于地表半空间的瞬变电磁一维正反演已达到实用阶段,但是在隧道全空间中,其反演成果与实际地质情况相差较大,研究隧道全空间瞬变电磁反演理论就很有必要。考虑隧道全空间瞬变电磁效应,并对一维半空间反演公式进行修正,使其能应用到一维全空间。论文主要开展了以研究工作： 1.论文应用数值模拟对电磁学中“烟圈效应”进行模拟,从定性和定量角度对“烟圈效应”的进行验证； 2.应用软件建立三维全空间模型和半空间模型,分析比较全空间和半空间瞬变电磁效应的区别和联系,找到两者之间的联系； 3.利用对称性建立模型模拟全空间和半空间瞬变电磁效应,得到大量数据进行分析,并对一维反演解析式进行修正。通过对数值模拟结果的分析总结可得：感应涡流在半空间中如“烟圈”一样向下向外传播,而全空间中是以发射线圈为中心往外扩散；隧道全空间中掌子面后方瞬变电磁效应很明显,而大地半空间中几乎没有感应涡流；全空间瞬变电磁效应比半空间要强烈,且存在某一个范围内的倍数关系。
[Abstract]:Transient electromagnetic method (TEM) is a new method for advanced geological exploration of poor water-rich geological bodies. The transient electromagnetic method is sensitive to the response of low-resistivity geological bodies, so the prediction advantages of low-resistivity geological bodies such as mud-filled water-filled caverns, water-filled faults, and mud-filled water-filled broken zones are obvious. At present, the transient electromagnetic one-dimensional forward and inverse modeling based on surface half-space has reached a practical stage, but in the whole tunnel space, the inversion results are quite different from the actual geological situation, so it is necessary to study the theory of tunnel full-space transient electromagnetic inversion. Considering the transient electromagnetic effect in the tunnel, the one-dimensional half-space inversion formula is modified so that it can be applied to one-dimensional full-space. The thesis mainly carries out the research work: 1. In this paper, numerical simulation is used to simulate the "smoke ring effect" in electromagnetism, and the "smoke ring effect" is verified from the qualitative and quantitative point of view. 2. Three dimensional full-space model and half-space model are established by using software, and the difference and relation between full-space and semi-space transient electromagnetic effects are analyzed and compared, and the relationship between them is found. 3. The symmetry model is used to simulate the transient electromagnetic effects in full space and half space. A large number of data are obtained and the one-dimensional inversion solution is modified. Through the analysis and summary of the numerical simulation results, it can be concluded that the induced eddy current propagates downwards in the half-space like a "smoke ring", while in the whole space it diffuses outwards with the launching coil as the center; The transient electromagnetic effect behind the palm surface in the tunnel is obvious, but there is almost no induced eddy current in the earth half-space, and the transient electromagnetic effect in the whole space is stronger than that in the half-space, and there exists a multiple relation in a certain range.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U452.11

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