A method for identifying the types of subsurface heterogenous bodies based on surface spectral disturbance features

Abstract

The invention discloses a method for identifying the category of shallow underground heterogeneous bodies based on surface wave spectrum disturbance characteristics, comprising: arranging a reference survey line near a suspicious area of ​​the heterogeneous body, performing two-dimensional Fourier transform on the test signal to obtain frequency-wave number domain spectrum, the average phase velocity is obtained from the spectral ridge; one-dimensional Fourier transform is performed on the test signal at the measuring point to obtain the offset-frequency domain spectral cloud map, and the offset-frequency domain spectral cloud map is converted from the average phase velocity to Offset-wavelength domain spectrogram, used as a reference spectrogram. Arrange a test line in the suspicious area to obtain a test spectral cloud map, compare it with the reference spectral cloud map, predict the buried depth and position of the heterogeneous body by the corresponding wavelength and offset distance of the spectral cloud map feature disturbance, and identify the heterogeneous body by the relative weakening or enhancement of the spectral intensity. body category. The invention obtains the surface wave field spectral cloud map of the offset distance-wavelength domain through the vibration response signal of a set of surface measuring points, and can predict the orientation and buried depth of the heterogeneous body and identify the heterogeneous body type by analyzing the disturbance characteristics of the spectral map.

Description

technical field [0001] The invention relates to the technical field of underground shallow heterogeneous body detection in geotechnical engineering or municipal engineering, in particular to a method for identifying categories of underground shallow heterogeneous bodies based on surface wave spectrum disturbance features. Background technique [0002] In geotechnical engineering or municipal work, air-filled or water-filled underground air-raid shelters, karst caves, pipelines, soft soils, silts, etc. are often encountered. The shear wave velocity (or stiffness) of these heterogeneous bodies is lower than that of the surrounding medium, and they are soft bodies. Heterogeneous bodies such as floating stones and concrete blocks have higher stiffness than the surrounding medium and are hard bodies. When the site contains soft bodies or hard bodies, it will affect the construction safety and project quality, especially in the process of tunnel shield construction, the following ...

AI Technical Summary

Problems solved by technology

Caves are just a special case of soft bodies. Shallow soft bodies and hard bodies have different surface wave scattering characteristics from caves. Various analysis methods for cave detection are applied to the detection and analysis of shallow soft and hard bodies underground. May lead to omission or misjudgment

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