Modified Cam Clay - geomechanics/mpm GitHub Wiki

{

    "materials": [
        {
            "id" : 0,
            "type": "ModifiedCamClay2D",
            "density": 2000,
            "shear_modulus": 2E7,
            "poisson_ratio": 0.3,
            "ocr": 1,
            "pc0": 6.0E+6,
            "m": 1.07,
            "lambda": 0.11,
            "kappa": 0.008,
            "p_ref": 6.0E+6,
            "e_ref": 0.38,
            "three_invariants": false,
            "subloading": true,
            "subloading_u": 100,
            "bonding": true,
            "mc_a": 1.2E+7,
            "mc_b": 1,
            "mc_c": 1.2E+7,
            "mc_d": 10,
            "s_h": 1,
            "m_degradation": 1,
            "m_shear": 2.4E+9
        }
    ]

}

• "id" is the material ID corresponding to a subset (or all) of the generated material points.
• "type" is either "ModifiedCamClay2D" or "ModifiedCamClay3D".
• "density" is material density.
• "shear_modulus" is the constant elastic parameter shear modulus.
• "poisson_ratio" is the constant elastic parameter Poisson's ratio.
• "ocr" is the over consolidation ratio. OCR can be replaced with porosity or initial void ratio values.
• "pc0" is the initial preconsolidation pressure.
• "m" is the slope of the critical line.
• "lambda" is the virgin compression index.
• "kappa" is the swell/recompression index.
• "p_ref" is the reference effective mean pressure.
• "e_ref" is the void ratio based at the reference effective mean pressure.
• "three_invariants" flag is set true to vary the critical stress ratio based on Lode's angle.
• "subloading" flag is set true for the subloading option.
• "bonding" flag is set true for the bonding option.
• "subloading_u" is the subloading parameter u.
• "mc_a" and "mc_b" are the paramters a and b, for dilation part of the bonding preconsolidation pressure.
• "mc_c" and "mc_d" are the paramters c and d, for cohesion part of the bonding preconsolidation pressure.
• "s_h" is the initial saturation of bonding effect in the range [0,1].
• "m_degradation" is the degradation parameter for preconsolidation pressure.
• "m_shear" is the bonding parameter for shear modulus.

Further details of the subloading and bonded behavior are provided in [1].

References

[1] Uchida, Shun, Kenichi Soga, and Koji Yamamoto. "Critical state soil constitutive model for methane hydrate soil." Journal of Geophysical Research: Solid Earth 117.B3 (2012).