Heterogeneity and soil element testing

    Research output: Contribution to journalArticle

    11 Citations (Scopus)

    Abstract

    Studies of strains within granular assemblies using digital image correlation have shown that as the resolution of observation becomes finer so the detail of the local variations of strains becomes more complex. The scale of this observed complexity is typically of the order of a few (5-10?) particles. The notion of a localised shear band of uniform shear or volumetric strain is not easily supported. In addition, studies reveal somewhat regular patterns of heterogeneity within samples which have been subjected to uniform external boundary deformations. A heterogeneous state is the natural state for granular materials. These observations have implications for the scales that should be adopted for testing of granular materials either in single-element or in physical model tests. Testing of a single element of a size that just accommodates a single region of 'localisation' will inevitably impose constraints on the particles in this region. On the other hand, one can envisage a representative element that is uniformly heterogeneous. Such an element would need to have dimensions that are large in comparison with the dimensions of the building blocks of the patterns of heterogeneity. These would define a length scale that is two orders of magnitude greater than typical particle sizes.
    Original languageEnglish
    Pages (from-to)101-106
    Number of pages6
    JournalGeotechnique Letters
    Volume2
    Issue number3
    DOIs
    Publication statusPublished - 3 Sep 2012

    Fingerprint

    Granular materials
    Soils
    shear band
    Testing
    digital image
    model test
    soil
    Shear bands
    particle size
    Particle size
    material
    particle
    comparison

    Keywords

    • fabric/structure of soils
    • particle-scale behaviour
    • sands
    • laboratory tests
    • strain localisation
    • model tests

    Cite this

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    title = "Heterogeneity and soil element testing",
    abstract = "Studies of strains within granular assemblies using digital image correlation have shown that as the resolution of observation becomes finer so the detail of the local variations of strains becomes more complex. The scale of this observed complexity is typically of the order of a few (5-10?) particles. The notion of a localised shear band of uniform shear or volumetric strain is not easily supported. In addition, studies reveal somewhat regular patterns of heterogeneity within samples which have been subjected to uniform external boundary deformations. A heterogeneous state is the natural state for granular materials. These observations have implications for the scales that should be adopted for testing of granular materials either in single-element or in physical model tests. Testing of a single element of a size that just accommodates a single region of 'localisation' will inevitably impose constraints on the particles in this region. On the other hand, one can envisage a representative element that is uniformly heterogeneous. Such an element would need to have dimensions that are large in comparison with the dimensions of the building blocks of the patterns of heterogeneity. These would define a length scale that is two orders of magnitude greater than typical particle sizes.",
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    author = "{Muir Wood}, D.",
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    Heterogeneity and soil element testing. / Muir Wood, D.

    In: Geotechnique Letters, Vol. 2, No. 3, 03.09.2012, p. 101-106.

    Research output: Contribution to journalArticle

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    N2 - Studies of strains within granular assemblies using digital image correlation have shown that as the resolution of observation becomes finer so the detail of the local variations of strains becomes more complex. The scale of this observed complexity is typically of the order of a few (5-10?) particles. The notion of a localised shear band of uniform shear or volumetric strain is not easily supported. In addition, studies reveal somewhat regular patterns of heterogeneity within samples which have been subjected to uniform external boundary deformations. A heterogeneous state is the natural state for granular materials. These observations have implications for the scales that should be adopted for testing of granular materials either in single-element or in physical model tests. Testing of a single element of a size that just accommodates a single region of 'localisation' will inevitably impose constraints on the particles in this region. On the other hand, one can envisage a representative element that is uniformly heterogeneous. Such an element would need to have dimensions that are large in comparison with the dimensions of the building blocks of the patterns of heterogeneity. These would define a length scale that is two orders of magnitude greater than typical particle sizes.

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    KW - model tests

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