Modeling micro-cracking behavior of Bukit Timah granite using grain-based model

Rock strength and deformation behavior has long been recognized to be closely related to the microstructure and the associated micro-cracking process. A good understanding of crack initiation and coalescence mechanisms will thus allow us to account for the variation of rock strength and deformation...

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Main Authors: Peng, Jun, Wong, Louis Ngai Yuen, Teh, Cee Ing, Li, Zhihuan
Other Authors: School of Civil and Environmental Engineering
Format: Article
Language:English
Published: 2020
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Online Access:https://hdl.handle.net/10356/141632
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Institution: Nanyang Technological University
Language: English
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spelling sg-ntu-dr.10356-1416322020-06-09T09:20:33Z Modeling micro-cracking behavior of Bukit Timah granite using grain-based model Peng, Jun Wong, Louis Ngai Yuen Teh, Cee Ing Li, Zhihuan School of Civil and Environmental Engineering Engineering::Civil engineering Grain-based Model Grain Boundary Cracks Rock strength and deformation behavior has long been recognized to be closely related to the microstructure and the associated micro-cracking process. A good understanding of crack initiation and coalescence mechanisms will thus allow us to account for the variation of rock strength and deformation properties from a microscopic view. This paper numerically investigates the micro-cracking behavior of Bukit Timah granite by using a grain-based modeling approach. First, the principles of grain-based model adopted in the two-dimensional Particle Flow Code and the numerical model generation procedure are reviewed. The micro-parameters of the numerical model are then calibrated to match the macro-properties of the rock obtained from tension and compression tests in the laboratory. The simulated rock properties are in good agreement with the laboratory test results with the errors less than ±6%. Finally, the calibrated model is used to study the micro-cracking behavior and the failure modes of the rock under direct tension and under compression with different confining pressures. The results reveal that when the numerical model is loaded in direct tension, only grain boundary tensile cracks are generated, and the simulated macroscopic fracture agrees well with the results obtained in laboratory tests. When the model is loaded in compression, the ratio of grain boundary tensile cracks to grain boundary shear cracks decreases with the increase in confining pressure. In other words, the results show that as the confining pressure increases, the failure mechanism changes from tension to shear. The simulated failure mode of the model changes from splitting to shear as the applied confining pressure gradually increases, which is comparable with that observed in laboratory tests. The grain-based model used in this study thus appears promising for further investigation of microscopic and macroscopic behavior of crystalline rocks under different loading conditions. MOE (Min. of Education, S’pore) 2020-06-09T09:20:33Z 2020-06-09T09:20:33Z 2017 Journal Article Peng, J., Wong, L. N. Y., Teh, C. I., & Li, Z. (2018). Modeling micro-cracking behavior of Bukit Timah granite using grain-based model. Rock Mechanics and Rock Engineering, 51(1), 135-154. doi:10.1007/s00603-017-1316-x 0723-2632 https://hdl.handle.net/10356/141632 10.1007/s00603-017-1316-x 2-s2.0-85029084778 1 51 135 154 en Rock Mechanics and Rock Engineering © 2017 Springer-Verlag GmbH Austria. All rights reserved.
institution Nanyang Technological University
building NTU Library
country Singapore
collection DR-NTU
language English
topic Engineering::Civil engineering
Grain-based Model
Grain Boundary Cracks
spellingShingle Engineering::Civil engineering
Grain-based Model
Grain Boundary Cracks
Peng, Jun
Wong, Louis Ngai Yuen
Teh, Cee Ing
Li, Zhihuan
Modeling micro-cracking behavior of Bukit Timah granite using grain-based model
description Rock strength and deformation behavior has long been recognized to be closely related to the microstructure and the associated micro-cracking process. A good understanding of crack initiation and coalescence mechanisms will thus allow us to account for the variation of rock strength and deformation properties from a microscopic view. This paper numerically investigates the micro-cracking behavior of Bukit Timah granite by using a grain-based modeling approach. First, the principles of grain-based model adopted in the two-dimensional Particle Flow Code and the numerical model generation procedure are reviewed. The micro-parameters of the numerical model are then calibrated to match the macro-properties of the rock obtained from tension and compression tests in the laboratory. The simulated rock properties are in good agreement with the laboratory test results with the errors less than ±6%. Finally, the calibrated model is used to study the micro-cracking behavior and the failure modes of the rock under direct tension and under compression with different confining pressures. The results reveal that when the numerical model is loaded in direct tension, only grain boundary tensile cracks are generated, and the simulated macroscopic fracture agrees well with the results obtained in laboratory tests. When the model is loaded in compression, the ratio of grain boundary tensile cracks to grain boundary shear cracks decreases with the increase in confining pressure. In other words, the results show that as the confining pressure increases, the failure mechanism changes from tension to shear. The simulated failure mode of the model changes from splitting to shear as the applied confining pressure gradually increases, which is comparable with that observed in laboratory tests. The grain-based model used in this study thus appears promising for further investigation of microscopic and macroscopic behavior of crystalline rocks under different loading conditions.
author2 School of Civil and Environmental Engineering
author_facet School of Civil and Environmental Engineering
Peng, Jun
Wong, Louis Ngai Yuen
Teh, Cee Ing
Li, Zhihuan
format Article
author Peng, Jun
Wong, Louis Ngai Yuen
Teh, Cee Ing
Li, Zhihuan
author_sort Peng, Jun
title Modeling micro-cracking behavior of Bukit Timah granite using grain-based model
title_short Modeling micro-cracking behavior of Bukit Timah granite using grain-based model
title_full Modeling micro-cracking behavior of Bukit Timah granite using grain-based model
title_fullStr Modeling micro-cracking behavior of Bukit Timah granite using grain-based model
title_full_unstemmed Modeling micro-cracking behavior of Bukit Timah granite using grain-based model
title_sort modeling micro-cracking behavior of bukit timah granite using grain-based model
publishDate 2020
url https://hdl.handle.net/10356/141632
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