Three-dimensional high definition electric resistivity exploration and direct imaging method

Abstract

The invention discloses a three-dimensional high-resolution resistivity prospecting and direct imaging method, the main content is to use a unipolar-dipole device for forming a mutually crossed orthogonal observation system in a total test area; the application of the three-dimensional high-resolution resistivity prospecting and direct imaging method can overcome the problems that the existing two-dimensional high-resolution resistivity prospecting method has inaccurate tunnel positioning and undetermined tunnel shape caused by the side effects. Compared with the general three-dimensional high-density resistivity prospecting method, the three-dimensional high-resolution resistivity prospecting and direct imaging method has high sensitivity to underground tunnels, thereby truly realizing the multiple coverage measurements of underground analysis and distinguishing units, having stronger anti-interference and static offset removing capabilities and easily realizing the rolling measurement and the seamless connection of the test area. The three-dimensional direct imaging method is fast and effective, and has no problem of difficult convergence. The method can obtain more precise information of the positions, the sizes and the shapes of the underground tunnels, thereby having great significance for the study of the shallow fine geological structure.

Description

technical field [0001] The invention belongs to the field of geological exploration, in particular to a three-dimensional high-resolution resistivity exploration and direct imaging method. Background technique [0002] In order to meet the demand for the detection of shallow fine geological structures, the high-density resistivity method was developed (Griffiths D H, Barker R D. Two-dimensional resistivity imaging and modeling in areas of complex geology. Journal of Applied Geophysics, 1993, 29: 211 ~226). The method adopts smaller electrode pitch and higher density electrode arrangement along the survey line, such as Wenner device, Schlumberger device, dipole-dipole, monopole-monopole, joint profile, intermediate gradient and other devices. Array observation, followed by inversion and fitting imaging. In the detection method with small pole distance and high density, the high-resolution resistivity method of monopole-dipole device is adopted (Oven T E. Detection and mappi...

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Problems solved by technology

[0004] In order to solve the problem of inaccurate positioning and shape when the existing two-dimensional high-resolution resistivity method detects unknown underground tunnels (the tunnel shape it depicts is the plane shape on the two-dimensional section), the general three-dimensional In addition to the high-density resistivity method being insensitive to isolated underground targets, the fitting method used in inversion imaging is computationally complex, time-consuming and difficult to converge; in order to obtain higher detection accuracy when detecting underground tunnels and the three-dimensional shape of underground targets, while providing a fast, accurate, and intuitive inversion interpretation method. The present invention provides a "three-dimensional high-resolution resistivity exploration and direct imaging method", which uses a uniform monopole-dipole device Orthogonal grids are laid out on the ground for area measurement. Through proper electrode arrangement and combination, multiple coverage observations of underground analysis and resolution units are formed in both vertical and horizontal directions. Direct graphic imaging changes from the original semicircle cross-drawing imaging to Hemispherical cross-drawing imaging, thus obtaining a more accurate spatial position of the tunnel within the detection depth range of the entire survey area, and more accurately reproducing the size and shape of the underground tunnel in real time in the field

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