The Numerical Simulation And Application Research Of The Magneto Telluric Sounding

With the mining scale and depth of coal mine increasing unceasingly, mine geological factors also become complex, coal mine geological disasters are more serious, so that they are enormous threat to the safety production in coal mine. This paper, combining with coal mine actual production, through theoretical analysis, numerical simulations, and application research,it researchs on magneto telluric method, in order that provides help for detecting geologic abnormal body.Firstly, it analyzes the basic principle of magneto telluric method which includes the electromagnetic wave propagation theory, the wave impedance and apparent resistivity, introduces the system composition of EH4 electromagnetic instrument and researchs on data processing problem, which contains work methods and techniques, interfering signal eliminate, near field source correction, inversion, graphics. Secondly, it adopted the EMAGE-2D software as system operation platform and finite element numerical simulation method established the goaf, low resistance body, fault land electric model and used the forward modeling SUFER rendering resistivity section. Through the under different conditions model calculation result analysis, it is conclusion that their apparent resistivity section distribution characteristics and changing rules, which provides a better theory basis for magneto telluric method detecting of sounding mined-out area, faults, the technology of low resistance body and data interpretation. Then, based on magneto telluric field is susceptible to the effects of undulating terrain topographic effect, it introduced the basic principle and calibration, used finite element numerical simulation and summarized the characteristics of two-dimensional topographic influence:the TM mode is more vulnerable than TE mode; the closer roads edge, the easier to be influenced by topography; mountain terrain is more vulnerable than valley; the bigger gap between the mountains and valleys, the easier to be influenced by topography; the more narrow top, the more susceptible to be influenced by terrain. Through the typical examples, terrain affects the shape of resistivity, so it used the "ratio method" for terrain correction and proved that this method can effectively eliminate the influence of 2d terrain.Through detection application examples of containing water strata, goaf, fault in coal mine, combined with ore party geological data and drilling verification, delineated the scope of geologic abnormal body, it proves that validation is similar toactual detecting and also proves the correctness of the simulation results and the effectiveness of correction and topography. It expands the application scope of magneto telluric technology and has good application value to coal exploration and geological disaster in coal mine.