Application Of High-Frequency Magnetotelluric Method In The Tunnel Exploration And Detection

In recent years, railway construction has a large amount of various projects, long tunnel of geological exploration has always been complex engineering problems. The paper connected with the practical application of a tunnel in closely. First of all, The paper has studied the basic theory of the high-frequency magnetotelluric, then introduced EH4 conductivity imaging device what has more general used in recent years as electromagnetic devices and made a more detailed study of theories and methods of the instrument including basic theory, working methods and methodology, data acquisition and data processing and related technology research and so on. Finally, the EH4 system has used in engineering example, focusing on analysis and interpretation of the results graph, and then based on the division of rock class, and put forward reasonable proposals for construction.EH4 system has a good application effect and prospect, but we know little about it at present because of the technology encapsulation is very rigorous. So we have to research its detailed technical in depth. Its content of output file is one key in this paper. If the content could be understood clearly, it can guarantee the follow-up data processing, and also can provide the basis for creating new processing method. In addition, eliminate noise research section in Hilbert-Huang Transform (HHT) is another important content in this paper. Hilbert-Huang Transform is a nonlinear method which can handle non-stationary time series. This technology is in the ascendant and used widely in many areas at present. Its theoretical basis is studied, and then through the analysis the application of data processing in EH4 system combined with examples, and the results is obtained satisfactorily by practice.The major research content and the achievements of the thesis are depicted as follows:(1) We have discussed the entire data acquisition and data processing of EH4 system in detail and the operation and inversion mapping techniques on IMAGEM;(2) Has read Y documents of EH4 file successfully, and analysis the output files in detail;(3) To find a simple and effective method of terrain correction, and can be well applied in practical work; (4) Made the Hilbert spectrum and marginal spectrum by programming, and provides a new approach To eliminate the noise in the data processing;(5) Segment analysis the Figure of Geophysical results with an engineering example, to some extent provided a reference for the geophysical interpretation.