Attenuation Analysis of Rayleigh Waves Used to Locate Shallow Manmade Tunnels

Abstract

The Attenuation Analysis of Rayleigh Waves (AARW) algorithm was applied to multi-channel surface wave seismic data acquired at two test sites for the purpose of locating manmade tunnels in the Earth's shallow subsurface. The surface wave data were acquired by incrementally moving a 24-channel geophone array and source along a traverse oriented perpendicular to the center-line of the tunnel. The near source-receiver offsets were 3 & 6 m, respectively; the 4.5 Hz geophones were spaced at 0.5 m. The geophone array geometry was optimized for nominal tunnel depths and diameters of ~1 m. Using AARW, the authors were able to reliably determine tunnel locations and delineate void geometries. Confidence levels and uncertainties with respect to void locations and geometries are discussed herein. Electrical resistivity or GPR data were acquired along each traverse for comparison purposes. This study demonstrates that the AARW algorithm may enable engineers to detect tunnels and estimate the geometry of the same.

Meeting Name

43rd U.S. Rock Mechanics Symposium and 4th U.S.-Canada Rock Mechanics Symposium (2009: Jun. 28-Jul.1, Asheville, NC)

Department(s)

Geosciences and Geological and Petroleum Engineering

Second Department

Electrical and Computer Engineering

Sponsor(s)

Leonard Wood Institute

Keywords and Phrases

Manmade Tunnels; Surface Wave Seismic Data; Rayleigh waves

Document Type

Article - Conference proceedings

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2009 American Rock Mechanics Association (ARMA), All rights reserved.

Publication Date

01 Jul 2009

Link to Full Text

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