Shear modulus of cohesionless soil: variation with stress and strain level

Martin Fahey

    Research output: Contribution to journalArticle

    20 Citations (Scopus)

    Abstract

    The value of the secant shear modulus (G) of sand measured in cyclic tests reduces as the amplitude of cycling increases. As a first approximation, it is assumed that the curve joining the extreme points of stress-strain (tau-gamma) loops of different amplitudes (a so-called "backbone curve") is hyperbolic. The shear strength (tau(max)) of sand is directly proportional to the mean effective confining pressure (p'), whereas the maximum shear modulus (G(o)) is proportional to (p')n, with n being between 0.4 and 0.5. Based on these assumptions, it is shown that at the same shear strain level, different G/G(o) values should be expected at different p' values. One of the features of a hyperbolic tau-gamma-curve is that there is a unique linear relationship between G/G(o) and normalized shear stress level (defined as tau/tau(max)), independent of p'. Therefore, considering the normalized shear stress level rather than the shear strain level may be a more logical and unifying way of examining the variation in G/G(o).
    Original languageEnglish
    Pages (from-to)157-161
    JournalCanadian Geotechnical Journal
    Volume29
    Issue number1
    DOIs
    Publication statusPublished - 1992

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    Shear strain
    Shear stress
    Sand
    Elastic moduli
    Soils
    Joining
    Shear strength

    Cite this

    @article{a20cb9328d394a95a6055528c81f3c89,
    title = "Shear modulus of cohesionless soil: variation with stress and strain level",
    abstract = "The value of the secant shear modulus (G) of sand measured in cyclic tests reduces as the amplitude of cycling increases. As a first approximation, it is assumed that the curve joining the extreme points of stress-strain (tau-gamma) loops of different amplitudes (a so-called {"}backbone curve{"}) is hyperbolic. The shear strength (tau(max)) of sand is directly proportional to the mean effective confining pressure (p'), whereas the maximum shear modulus (G(o)) is proportional to (p')n, with n being between 0.4 and 0.5. Based on these assumptions, it is shown that at the same shear strain level, different G/G(o) values should be expected at different p' values. One of the features of a hyperbolic tau-gamma-curve is that there is a unique linear relationship between G/G(o) and normalized shear stress level (defined as tau/tau(max)), independent of p'. Therefore, considering the normalized shear stress level rather than the shear strain level may be a more logical and unifying way of examining the variation in G/G(o).",
    author = "Martin Fahey",
    year = "1992",
    doi = "10.1139/t92-017",
    language = "English",
    volume = "29",
    pages = "157--161",
    journal = "Canadian Geotechnical Journal",
    issn = "0008-3674",
    publisher = "CANADIAN SCIENCE PUBLISHING, NRC RESEARCH PRESS",
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    }

    Shear modulus of cohesionless soil: variation with stress and strain level. / Fahey, Martin.

    In: Canadian Geotechnical Journal, Vol. 29, No. 1, 1992, p. 157-161.

    Research output: Contribution to journalArticle

    TY - JOUR

    T1 - Shear modulus of cohesionless soil: variation with stress and strain level

    AU - Fahey, Martin

    PY - 1992

    Y1 - 1992

    N2 - The value of the secant shear modulus (G) of sand measured in cyclic tests reduces as the amplitude of cycling increases. As a first approximation, it is assumed that the curve joining the extreme points of stress-strain (tau-gamma) loops of different amplitudes (a so-called "backbone curve") is hyperbolic. The shear strength (tau(max)) of sand is directly proportional to the mean effective confining pressure (p'), whereas the maximum shear modulus (G(o)) is proportional to (p')n, with n being between 0.4 and 0.5. Based on these assumptions, it is shown that at the same shear strain level, different G/G(o) values should be expected at different p' values. One of the features of a hyperbolic tau-gamma-curve is that there is a unique linear relationship between G/G(o) and normalized shear stress level (defined as tau/tau(max)), independent of p'. Therefore, considering the normalized shear stress level rather than the shear strain level may be a more logical and unifying way of examining the variation in G/G(o).

    AB - The value of the secant shear modulus (G) of sand measured in cyclic tests reduces as the amplitude of cycling increases. As a first approximation, it is assumed that the curve joining the extreme points of stress-strain (tau-gamma) loops of different amplitudes (a so-called "backbone curve") is hyperbolic. The shear strength (tau(max)) of sand is directly proportional to the mean effective confining pressure (p'), whereas the maximum shear modulus (G(o)) is proportional to (p')n, with n being between 0.4 and 0.5. Based on these assumptions, it is shown that at the same shear strain level, different G/G(o) values should be expected at different p' values. One of the features of a hyperbolic tau-gamma-curve is that there is a unique linear relationship between G/G(o) and normalized shear stress level (defined as tau/tau(max)), independent of p'. Therefore, considering the normalized shear stress level rather than the shear strain level may be a more logical and unifying way of examining the variation in G/G(o).

    U2 - 10.1139/t92-017

    DO - 10.1139/t92-017

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    JO - Canadian Geotechnical Journal

    JF - Canadian Geotechnical Journal

    SN - 0008-3674

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    ER -