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Micromechanics modelling for the stress-strain-strength behavior of granular materials
Abstract
The characterization of the developed constitutive law for granular material based on micromechanics approach is performed by comparing both qualitatively and quantitatively the predicted stress-strain and volume change behavior for idealized materials with the published experimental results on various granular materials. A constitutive law for granular material is derived based on the micromechanics approach, taking into account the mechanisms of sliding and separation of particles under large deformation. One of the major obstacles to account for the particle sliding associated with large deformation is the non-uniform strain field. This problem is tackled by introducing a distributive law which describes the heterogeneous field of strain. The developed approach treats the material at three levels, namely, representative unit, micro-element and inter-particle contact. Based on this, the constitutive laws for each level are derived and the overall stress-strain relationship is expressed in terms of inter-particle contact behavior. The developed micromechanics based constitutive model for granular material has been evaluated by comparing the predicted stress-strain and volume change behavior of idealized materials with that observed from experiments on sands under various loading conditions. For small strain conditions, the model is evaluated for its predictive ability of initial moduli, secant moduli and damping ratio under low amplitude loading. For large strain conditions, the model is evaluated for its capability in predicting stress-strain-strength behavior under various stress paths. In all the predictions, three parameters are used, which represent the normal and shear stiffness and inter-particle friction angle of contact. Although the material structure and particle shape are idealized in all the predictions, the predicted behavior is found to be remarkably similar to that observed from experiments. The potential capability of the micromechanics based constitutive theory is illustrated and the model performance is discussed on various aspects of granular material behavior, such as inherent and stress-induced anisotropy, strength and residual strength, path dependency, yielding and plastic flow, dilatancy, locked-in stress and non-coaxial behavior under rotation of principal stress.
Subject Area
Civil engineering
Recommended Citation
Kabir, Mohammed Golam, "Micromechanics modelling for the stress-strain-strength behavior of granular materials" (1992). Doctoral Dissertations Available from Proquest. AAI9233079.
https://scholarworks.umass.edu/dissertations/AAI9233079