Exploration in challenging mountainous areas,as recognized for its significant difficulty,is always taken as an important subject in railway engineering.Geophysical methods,characterized by portability,high operational efficiency,and intuitive data representation,are applicable to investigations in such difficult terrains.Large-span chambers,with their extensive lateral extents,cannot be adequately surveyed by a single geophysical profile line,demanding higher precision approaches.This paper presented an array-based 3D audio-frequency magnetotelluric exploration method tailored for investigating large-span chambers in challenging mountainous areas.The profile line layout comprehensively considers tunnel depth,chamber span,uniformity of measurement point distribution,and the impact of edge effects on exploration accuracy,thereby significantly enhancing the quality of field data.Through joint inversion,a detailed 3D apparent resistivity database was constructed,visually illustrating the spatial distribution of underground geological anomalies.The study outcomes effectively reveal the morphology of fractured and water-rich rock masses beneath the surface,providing valuable references for tunnel construction designs.
large-span chambersaudio-frequency magnetotelluric methodarray-based 3D profile linesrailway tunnel exploration
维普
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