The Application Of EH-4Magnetotelluric Method For Engineering Geological Survey In Yunnan Region

With the fast development of the high-speed railway in China, we need reliableand more accurate methods to prospect and solve problems in Engineering Geologyfield, Magnetotelluricmothod is a kind of Geophysical method which has been widelyused for solving these problems, it has advantages such as deep exploration depth,lower cost, sensitive to the layer with low resistivity, high resolution, etc. Includingthese methods, EH-4can be wider used for Engineering Geology exploration, becauseit has a smaller volume and relative portable.This paper is about the application of EH-4to explore and solve EngineeringGeology problem, the objects of study are Xianghe tunnel of Guangda railway,Xiaojiang active fault zone in Yiliang, soft soil distribution at New Kunming SouthRailway Staion.Yunnan province is a mountainous region, it has complicated terrain conditionsand geological structure, especially cavities are highly developed there, therefore, theEngineering geological conditions are not good, there are many unknown factorsduring the engineering design and constructions. Meanwhile, it is sensitive to theinfluence of high-voltage lines when implementing EH-4near the region wherehuman live, all of these result in many new topics for us to explore and solve.The influences of various sources of interference to the quality of data and andcorresponding solutions were listed in this paper, these are reliable references for dataprocessing and interpretation. We implemented new wiring layout at swamp regions,thus expanded the area for EH-4exploration. Under this background, with the acquisition of large amount of first-handinformation, implement pre-processing with IMGEM, combining the field record andthe possible influences of various interferences, choosing the data with higher qualityas possible, generating resistivity sectional plot, then combining the geological andgeophysical information that we’ve already known to analyze and do theinterpretation, we can delineate the geological structures that we are interested in onthe sectional plot to generate the final interpretation plot. In this thesis, we didexploration and research in Xianghe tunnel, Xiaojiang active fault zone and NewKunming South Railway Station, excluding various interferences as far as possible,and compare the results of these three exploration areas, improved the accuracy ofEH-4exploration, thus generating some degree of significance to the EH-4exploration in the future.