Application of Wavelets in Detection of Cavities Under Pavements by Surface Waves

Abstract

Application of wavelet transforms in the detection of underground shallow cavities is investigated. Wave propagation is simulated through a transient response analysis on an axisymmetric finite element model. Cavities in a homogeneous half-space and a pavement system of a variety of shapes and embedment depths are considered. The continuous wavelet transform is introduced as a new tool for cavity detection. Effects of different types of cavities on power spectral surfaces (power spectral amplitudes versus frequency and receiver location) and Gaussian wavelet time-frequency maps (wavelet transform coefficients versus time and frequency) are studied. Results show strong energy concentration in power spectral surfaces right in front of a cavity in certain frequency bands. Time and frequency signatures of waves reflected from near and far faces of the cavity can be clearly observed in the wavelet time-frequency maps. These observations are used to locate and estimate the size of the cavity. It is demonstrated that the wavelet transform is a promising analysis tool for cavity detection and characterization.

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References

Cooper

S. S.

, and Ballard

R. F.

. Geophysical Exploration for Cavity Detection in Karst Terrain. In Proc., Symposium on Geotechnical Aspects of Karst Terrains: Exploration, Foundation Design and Preference, and Remedial Measures. Geotechnical Special Publication 14. ASCE, New York, 1988, pp. 25–39.

Belesky

R. M.

, and Hardy

H. R.

. Seismic and Microseismic Methods for Cavity Detection and Stability Monitoring of Near-Surface Voids. In Proc., 27th U.S. Symposium on Rock Mechanics—Rock Mechanics: Key to Energy Production, University of Alabama, Tuscaloosa, 1986, pp. 248–258.

Al-Shayea

N. A.

, Woods

R. D.

, and Gilmore

. SASW and GPR to Detect Buried Objects. In Proc., Symposium on Application of Geophysics to Engineering and Environmental Problems, EEGS, Wheat Ridge, Colo., 1994, pp. 543–560.

Gucunski

, Ganji

, and Maher

. Effects of Obstacles on Rayleigh Wave Dispersion Obtained from the SASW Test. Soil Dynamics and Earthquake Engineering, Vol. 15, No. 4, 1996, pp. 223–231.

Ganji

, Gucunski

, and Maher

. Detection of Underground Obstacles by SASW Method: Numerical Aspects. Journal of Geotechnical and Geoenvironmental Engineering, Vol. 123, No. 3, March 1997, pp. 212–219.

Luke

B. A.

, and Chase

D. S.

. Detecting Caves Using Seismic Surface Waves: A Feasibility Study. In The Engineering Geology and Hydro-geology of Karst Terrains, Balkema, Rotterdam, 1997, pp. 419–424.

Philips

, Cascante

, and Hutchinson

D. J.

. Seismic Surface Waves To Detect Underground Voids. In Proc., Symposium on the Application of Geophysics to Engineering and Environmental Problems, Arlington, Va., Feb. 2000, pp. 29–37.

Philips

, Cascante

, and Hutchinson

D. J.

. The Innovative Use of Seismic Surface Waves for Void Detection and Material Characterization. In Proc., Symposium on the Application of Geophysics to Engineering and Environmental Problems, Las Vegas, Nev., Feb. 2002, pp. 1–10.

Zerwer

, Cascante

, and Hutchinson

D. J.

. Parameter Estimation in Finite Element Simulation of Rayleigh Waves. Journal of Geotechnical and Environmental Engineering, Vol. 128, No. 3, March 2002, pp. 250–261.

10.

Liu

C. S.

, and Chan

A. K.

. Wavelet Toolware: Software for Wavelet Training (Part I: Wavelet Theory). Academic Press, 1998.

11.

Newland

D. E.

Wavelet Analysis of Vibration, Part I: Theory. Journal of Vibration and Acoustics, Vol. 116, Oct. 1994, pp. 409–416.

12.

Newland

D. E.

, Random Vibrations: Spectral and Wavelet Analysis. John Wiley and Sons, Inc., New York, 1993.

13.

Kijewski

T. L.

, and Kareem

. Wavelet Transforms for System Identification and Associated Processing Concerns. In Proc., 15th ASCE Engineering Mechanics Conference, Columbia University, New York, June 2002.

14.

Kaiser

A Friendly Guide to Wavelets. Kaiser, Birkhauser, Boston, 1994.

15.

Walker

J. S.

A Primer on Wavelets and Their Scientific Applications. CRC Press, 1999.

16.

Gucunski

, Kristic

, and Maher

. Field Implementation of the Surface Waves for Obstacle Detection (SWOD) Method. In Proc., 15th World Conference on Non-Destructive Testing, Rome, Oct. 2000.