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[1] The mechanical response of geomaterials is highly influenced by geometrical and material heterogeneity. To date, most modeling practices consider heterogeneity qualitatively and their choice of input parameters can be subjective. In this study, a novel approach to combine a detailed micro-scale characterization with modeling of heterogeneous geomaterials is presented. By conducting grid micro-indentation and micro-scratch tests, the instrumented indentation modulus and fracture toughness of the constituent phases of a crystalline rock were obtained and used as accurate input parameters for the numerical models. Additionally, X-ray micro Computed Tomography (CT) was used to obtain the spatial distribution of minerals, and thin section analysis was performed to quantify the microcrack density. Finally, a Brazilian disc test was modeled using a Combined Finite-Discrete element method (FEM/DEM) code. Compared with the laboratory results of a sample that was initially CT scanned, the simulation results showed that by incorporating accurate micromechanical input parameters and the intrinsic rock geometric features such as spatial phase heterogeneity and microcracks, the numerical simulation could more accurately predict the mechanical response of the specimen, including the fracture patterns and tensile strength. It is believed that the proposed micromechanical approach for evaluating the material properties and the sample geometry can be readily applied to other problems to accurately model the mechanical behavior of heterogeneous geomaterials. |
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