Calibration of non-linear effective stress code for seismic analysis of excess pore pressures and liquefaction in the free field

R. Dobry, W. El-Sekelly, Tarek Abdoun

    Research output: Contribution to journalArticle

    Abstract

    The paper presents numerical predictions of excess pore pressure, liquefaction and settlement response of four centrifuge model tests of 6 m uniform deposits of saturated clean Ottawa sand, placed by dry pluviation and having a relative density ranging from 38% to 66%. The deposits were subjected to 1D uniform base shaking consisting of 10–15 cycles of peak acceleration ranging from 0.04 to 0.12 g. All predictions were conducted with the nonlinear effective stress numerical code Dmod2000. Significant effort was spent in calibrating Dmod2000 by matching the pore pressure and settlement measurements of the first shaking (S1) of a series of shakings conducted in centrifuge Experiment 3. This resulted in very good predictions of both pore pressures and settlement measured in this shaking S1. The exercise showed the importance for realistic simulations of having the correct soil compressibility and permeability. This calibrated version of Dmod2000 was used for a good pore pressure prediction of the preshaken deposit in the same Experiment 3 (S36), by modifying only one parameter in the undrained pore pressure model; and also well predicted pore pressure responses in Tests FFV3 and PFV1, without any change in the parameters of Dmod2000 except for use of the new input motions (Type B predictions). The experimental and numerical results showed that both cyclic shear stress/strains and upward water flow determine together the pore pressure buildup and liquefaction phenomena. The soil response is partially drained rather than undrained, and pore pressure dissipation does take place during shaking both before and after liquefaction occurs.

    Original languageEnglish (US)
    Pages (from-to)374-389
    Number of pages16
    JournalSoil Dynamics and Earthquake Engineering
    Volume107
    DOIs
    StatePublished - Apr 1 2018

    Fingerprint

    Pore pressure
    Liquefaction
    effective stress
    liquefaction
    pore pressure
    calibration
    Calibration
    prediction
    centrifuges
    Deposits
    Centrifuges
    centrifuge
    Well pressure
    Soils
    peak acceleration
    compressibility
    code
    analysis
    Compressibility
    model test

    ASJC Scopus subject areas

    • Civil and Structural Engineering
    • Geotechnical Engineering and Engineering Geology
    • Soil Science

    Cite this

    Calibration of non-linear effective stress code for seismic analysis of excess pore pressures and liquefaction in the free field. / Dobry, R.; El-Sekelly, W.; Abdoun, Tarek.

    In: Soil Dynamics and Earthquake Engineering, Vol. 107, 01.04.2018, p. 374-389.

    Research output: Contribution to journalArticle

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