Timelapse ultrasonic tomography for measuring damage localization in geomechanics laboratory tests.
Författare
Summary, in English
Variation of mechanical properties in materials can be detected non-destructively using ultrasonic measurements. In particular, changes in elastic wave velocity can occur due to damage, i.e., micro-cracking and particles debonding. Here the challenge of characterizing damage in geomaterials, i.e., rocks and soils, is addressed. Geomaterials are naturally heterogeneous media in which the deformation can localize, so that few measurements of acoustic velocity across the sample are not sufficient to capture the heterogeneities. Therefore, an ultrasonic tomography procedure has been implemented to map the spatial and temporal variations in propagation velocity, which provides information on the damage process. Moreover, double beamforming has been successfully applied to identify and isolate multiple arrivals that are caused by strong heterogeneities (natural or induced by the deformation process). The applicability of the developed experimental technique to laboratory geomechanics testing is illustrated using data acquired on a sample of natural rock before and after being deformed under triaxial compression. The approach is then validated and extended to time-lapse monitoring using data acquired during plane strain compression of a sample including a well defined layer with different mechanical properties than the matrix.
Avdelning/ar
Publiceringsår
2015
Språk
Engelska
Sidor
1389-1400
Publikation/Tidskrift/Serie
Journal of the Acoustical Society of America
Volym
137
Issue
3
Fulltext
Dokumenttyp
Artikel i tidskrift
Förlag
American Institute of Physics (AIP)
Ämne
- Geotechnical Engineering
Nyckelord
- Velocity measurement
- Mechanical properties
- Ultrasonic Tomography
- Ultrasonic velocity
Status
Published
ISBN/ISSN/Övrigt
- ISSN: 1520-8524