ISSN: 1945-7545
CODEN: GTJODJ
Published Online: 16 September 2011
Page Count: 10

Time-Lapse Monitoring of Fabric Changes in Granular Materials by Coda Wave Interferometry

Wuttke, F.
Modeling in Geomechanics, Bauhaus-Univ. Weimar, Weimar,

Asslan, M.
Modeling in Geomechanics, Bauhaus-Univ. Weimar, Weimar,

Schanz, T.
Chair of Foundation Engineering, Soil and Rock Mechanics, Ruhr-Univ. Bochum, Bochum,

(Received 2 November 2010; accepted 15 August 2011)

Abstract

The determination of wave velocities in soils captures an important role for small-strain parameter in constitutive modeling as well as in monitoring processes of the state. The wave velocity differs substantially with the porosity, surrounding pressure, degree of saturation and other parameters in soils. In particular when the environmental conditions are non-stationary. For studying the change of state parameters in granular materials, the identification of the velocity evolution can be a challenge in particular if the perturbations are small. We discuss the application of a new seismic method for geotechnical experiments—the Coda wave interferometry. The method is used to detect the wave velocities change related to small soil perturbations. Whereas the perturbations are caused by small changes in stress and void ratio. Different material, well-known sands and artificial glass beads are analysed in this experimental study by conventional volume measurements and seismic methods to detect the stress and porosity changes. The wave excitation and recording was done by piezoceramic bender elements. In result of the tests, the coda wave interferometry emphasized its large potential for the time-lapse monitoring of soils.

Keywords:
coda wave interferometry, wave propagation, bender element tests, granular materials

Paper ID: GTJ103546
DOI: 10.1520/GTJ103546
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