期刊
COMPUTERS AND GEOTECHNICS
卷 78, 期 -, 页码 203-217出版社
ELSEVIER SCI LTD
DOI: 10.1016/j.compgeo.2016.05.019
关键词
Rock microstructure; Distinct element method (DEM); Grain-based method; Heterogeneity
类别
资金
- NSERC Discovery Grants
A distinct element grain-based method (GBM) was developed to simulate the microstructure of rock-like materials. Using this method, a UDEC-GBM model can be readily constructed with a given mineral composition, allowing independent assignment of specific properties to both the grains and grain boundaries. Both intra-granular cracks cutting through the grains and inter-granular cracks developed along grain boundaries can be captured. These features allow a full incorporation of both geometric and mechanical heterogeneity at grain scale for simulating brittle rocks. The validity of the proposed UDEC-GBM approach was verified by simulating a low-porosity sandstone under compression and direct-shear tests. The UDEC-GBM was proved to be capable of reproducing many of the characteristics associated with brittle fracture in low-porosity sandstone. It was found that the model with unbreakable grains trends to under-estimate the crick initiation threshold, highlighting the importance of the incorporation of breakable grains when modeling micro-structure of brittle rocks. The numerical experiments suggested that examining the extent of the tensile stress zones alone may lead to a biased evaluation of tensile cracking at crack initiation. The tensile stress magnitude must also be taken into consideration. It was also found that a synthetic sandstone sample with relatively low ground boundary strength produces a more ductile post-peak behavior. Microscopic tensile strength of the grains has limited influence on the failure mechanism of the synthetic specimen under unconfined compression loading. The proposed GBM approach provides a very useful tool for studying grain-scale micro-mechanics of brittle rocks. (C) 2016 Elsevier Ltd. All rights reserved.
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