Assessment of Localized Deformations in Sand Using X-Ray Computed Tomography
- 1 September 2000
- journal article
- other
- Published by ASTM International in Geotechnical Testing Journal
- Vol. 23 (3), 274-299
- https://doi.org/10.1520/gtj11051j
Abstract
The internal fabric and localized deformation patterns of triaxial sand specimens were investigated using computed tomography (CT). Three displacement-controlled, conventional, drained axisymmetric (triaxial) experiments were conducted on dry Ottawa sand specimens at very low effective confining stresses (0.05, 0.52, and 1.30 kPa) in a microgravity environment aboard the Space Shuttle during the NASA STS-79 mission. CT scanning was performed on these flight specimens, as well as on an uncompressed specimen and a specimen tested in a terrestrial laboratory at 1.30 kPa effective confining stress. CT demonstrated high accuracy in detecting specimen inhomogeneity and localization patterns. Formation of deformation patters is dependent on the effective confining stress and gravity. Multiple symmetrical radial shear bands were observed in the specimens tested in a microgravity environment. In the axial direction, two major conical surfaces were developed. Nonsymmetrical spatial deformation was observed in the 1-G specimen. Analysis tools were developed to quantify the spatial density change. Void ratio variation within and outside the shear bands is calculated and discussed.Keywords
This publication has 14 references indexed in Scilit:
- Mechanics of Granular Materials at Low Effective StressesJournal of Aerospace Engineering, 1998
- Measuring physical density with X-ray computed tomographyNDT & E International, 1997
- Three‐dimensional quantitative textural analysis of metamorphic rocks using high‐resolution computed X‐ray tomography: Part I. Methods and techniquesJournal of Metamorphic Geology, 1997
- Three‐dimensional quantitative textural analysis of metamorphic rocks using high‐resolution computed X‐ray tomography: Part II. Application to natural samplesJournal of Metamorphic Geology, 1997
- Fractal Dimension and Lacunarity of Bulk Density Determined with X‐ray Computed TomographySoil Science Society of America Journal, 1996
- A rapid technique to determine bulk density of fine-grained sediments by X-ray computed tomographyJournal of Sedimentary Research, 1996
- Void ratio evolution inside shear bands in triaxial sand specimens studied by computed tomographyGéotechnique, 1996
- Calibration of constitutive models for granular materials using data from biaxial experimentsGéotechnique, 1985
- The Influence of Strains in Soil MechanicsGéotechnique, 1970
- Strip Integration in Radio AstronomyAustralian Journal of Physics, 1956