Extracting real-crack properties from non-linear elastic behaviour of rocks: abundance of cracks with dominating normal compliance and rocks with negative Poisson ratios

Vladimir Y. Zaitsev, Andrey V. Radostin, Elena Pasternak, Arcady Dyskin

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    6 Citations (Scopus)

    Abstract

    Results of examination of experimental data on non-linear elasticity of rocks using experimentally determined pressure dependences of P- and S-wave velocities from various literature sources are presented. Overall, over 90 rock samples are considered. Interpretation of the data is performed using an effective-medium description in which cracks are considered as compliant defects with explicitly introduced shear and normal compliances without specifying a particular crack model with an a priori given ratio of the compliances. Comparison with the experimental data indicated abundance (similar to 80 %) of cracks with the normal-toshear compliance ratios that significantly exceed the values typical of conventionally used crack models (such as penny-shaped cuts or thin ellipsoidal cracks). Correspondingly, rocks with such cracks demonstrate a strongly decreased Poisson ratio including a significant (similar to 45 %) portion of rocks exhibiting negative Poisson ratios at lower pressures, for which the concentration of not yet closed cracks is maximal. The obtained results indicate the necessity for further development of crack models to account for the revealed numerous examples of cracks with strong domination of normal compliance. Discovering such a significant number of naturally auxetic rocks is in contrast to the conventional viewpoint that occurrence of a negative Poisson ratio is an exotic fact that is mostly discussed for artificial structures.

    Original languageEnglish
    Pages (from-to)543-551
    Number of pages9
    JournalNonlinear Processes in Geophysics
    Volume24
    Issue number3
    DOIs
    Publication statusPublished - 5 Sep 2017

    Cite this

    @article{3fe28f2a74af422599f5aac8a6c8e08d,
    title = "Extracting real-crack properties from non-linear elastic behaviour of rocks: abundance of cracks with dominating normal compliance and rocks with negative Poisson ratios",
    abstract = "Results of examination of experimental data on non-linear elasticity of rocks using experimentally determined pressure dependences of P- and S-wave velocities from various literature sources are presented. Overall, over 90 rock samples are considered. Interpretation of the data is performed using an effective-medium description in which cracks are considered as compliant defects with explicitly introduced shear and normal compliances without specifying a particular crack model with an a priori given ratio of the compliances. Comparison with the experimental data indicated abundance (similar to 80 {\%}) of cracks with the normal-toshear compliance ratios that significantly exceed the values typical of conventionally used crack models (such as penny-shaped cuts or thin ellipsoidal cracks). Correspondingly, rocks with such cracks demonstrate a strongly decreased Poisson ratio including a significant (similar to 45 {\%}) portion of rocks exhibiting negative Poisson ratios at lower pressures, for which the concentration of not yet closed cracks is maximal. The obtained results indicate the necessity for further development of crack models to account for the revealed numerous examples of cracks with strong domination of normal compliance. Discovering such a significant number of naturally auxetic rocks is in contrast to the conventional viewpoint that occurrence of a negative Poisson ratio is an exotic fact that is mostly discussed for artificial structures.",
    keywords = "SEISMIC NOISE, SOLIDS, VELOCITIES, PRESSURE, MEDIA, WAVE, DRY, SENSITIVITY, DISSIPATION, MODULATION",
    author = "Zaitsev, {Vladimir Y.} and Radostin, {Andrey V.} and Elena Pasternak and Arcady Dyskin",
    year = "2017",
    month = "9",
    day = "5",
    doi = "10.5194/npg-24-543-2017",
    language = "English",
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    pages = "543--551",
    journal = "Nonlinear Processes in Geophysics",
    issn = "1023-5809",
    publisher = "Copernicus Gesellschaft mbH",
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    }

    TY - JOUR

    T1 - Extracting real-crack properties from non-linear elastic behaviour of rocks

    T2 - abundance of cracks with dominating normal compliance and rocks with negative Poisson ratios

    AU - Zaitsev, Vladimir Y.

    AU - Radostin, Andrey V.

    AU - Pasternak, Elena

    AU - Dyskin, Arcady

    PY - 2017/9/5

    Y1 - 2017/9/5

    N2 - Results of examination of experimental data on non-linear elasticity of rocks using experimentally determined pressure dependences of P- and S-wave velocities from various literature sources are presented. Overall, over 90 rock samples are considered. Interpretation of the data is performed using an effective-medium description in which cracks are considered as compliant defects with explicitly introduced shear and normal compliances without specifying a particular crack model with an a priori given ratio of the compliances. Comparison with the experimental data indicated abundance (similar to 80 %) of cracks with the normal-toshear compliance ratios that significantly exceed the values typical of conventionally used crack models (such as penny-shaped cuts or thin ellipsoidal cracks). Correspondingly, rocks with such cracks demonstrate a strongly decreased Poisson ratio including a significant (similar to 45 %) portion of rocks exhibiting negative Poisson ratios at lower pressures, for which the concentration of not yet closed cracks is maximal. The obtained results indicate the necessity for further development of crack models to account for the revealed numerous examples of cracks with strong domination of normal compliance. Discovering such a significant number of naturally auxetic rocks is in contrast to the conventional viewpoint that occurrence of a negative Poisson ratio is an exotic fact that is mostly discussed for artificial structures.

    AB - Results of examination of experimental data on non-linear elasticity of rocks using experimentally determined pressure dependences of P- and S-wave velocities from various literature sources are presented. Overall, over 90 rock samples are considered. Interpretation of the data is performed using an effective-medium description in which cracks are considered as compliant defects with explicitly introduced shear and normal compliances without specifying a particular crack model with an a priori given ratio of the compliances. Comparison with the experimental data indicated abundance (similar to 80 %) of cracks with the normal-toshear compliance ratios that significantly exceed the values typical of conventionally used crack models (such as penny-shaped cuts or thin ellipsoidal cracks). Correspondingly, rocks with such cracks demonstrate a strongly decreased Poisson ratio including a significant (similar to 45 %) portion of rocks exhibiting negative Poisson ratios at lower pressures, for which the concentration of not yet closed cracks is maximal. The obtained results indicate the necessity for further development of crack models to account for the revealed numerous examples of cracks with strong domination of normal compliance. Discovering such a significant number of naturally auxetic rocks is in contrast to the conventional viewpoint that occurrence of a negative Poisson ratio is an exotic fact that is mostly discussed for artificial structures.

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    KW - SOLIDS

    KW - VELOCITIES

    KW - PRESSURE

    KW - MEDIA

    KW - WAVE

    KW - DRY

    KW - SENSITIVITY

    KW - DISSIPATION

    KW - MODULATION

    U2 - 10.5194/npg-24-543-2017

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    JO - Nonlinear Processes in Geophysics

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