Characterization of rock heterogeneity and numerical verification

On the basis of microstructure analysis and image analysis, rock heterogeneity is modelled by the rock and tool (R-T2D) interaction code according to homogenisation theory. The simulated results predict very well the non-linear stress–strain behaviour and the progressive fracture process of heterogeneous rock material. It is found that the weak parts and subsequent fractures before localization represent an obvious statistically uniform characteristic. Therefore, a statistical method is used to model rock heterogeneity. The results from the statistical modelling are in surprisingly good agreement with those from the homogenisation modelling. Considering the research scale, the rock heterogeneity is characterized better by the Weibull statistical method as a few characteristic parameters: the homogeneous index and the elemental seed parameters of the R-T2D finite element network. Finally, a series of numerical experiments are conducted to validate that the characterization of rock heterogeneity is reasonable and feasible, and that the R-T2D code is stable, repeatable and a valuable tool to research the fracture process of heterogeneous material.

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