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An Extended Grain‐Based Model Accounting for Microstructures in Rock Deformation
Author(s) -
Zhang Yahui,
Wong Louis Ngai Yuen,
Chan Ka Kit
Publication year - 2019
Publication title -
journal of geophysical research: solid earth
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.983
H-Index - 232
eISSN - 2169-9356
pISSN - 2169-9313
DOI - 10.1029/2018jb016165
Subject(s) - voronoi diagram , classification of discontinuities , deformation (meteorology) , geology , fracture (geology) , microstructure , cracking , fracture toughness , materials science , fracture mechanics , grain size , bending , geotechnical engineering , geometry , composite material , mathematics , mathematical analysis
Reliable prediction of the rock fracturing process is a challenging issue in exploitation of deep earth resources in which artificial creation of complex fracture networks is employed. The grain‐based modeling (GBM) approach is a promising numerical technique for its unique capability to simulate the fracturing behavior of crystalline rocks. An extended grain‐based model is developed to improve the traditional Voronoi GBM from two aspects. First, digital image processing technique is presented to incorporate actual rock microstructures into the numerical model. Second, the effect of initial microcracks is considered by integrating a statistical discrete fracture network model into GBM. By simulating semicircular bending tests on 16 extended GBMs and 3 Voronoi GBMs, the effects of rock microstructures and initial microcracks on microcracking behavior and mechanical properties are analyzed. Cracking patterns are classified into four types for the first time with respect to fracture toughness and crack initiation threshold. The results indicate that the use of a statistical structure or a purely deterministic GBM without consideration of initial microcracks cannot realistically describe grain‐scale discontinuities, which likely leads to biased evaluations of the rock failure process.