Discrete Element Modeling on Mechanical Behavior of Heterogeneous Rock Containing X-Shaped Fissure under Uniaxial Compression

Based on the experimental results of an intact rock specimen under uniaxial compression, particle flow code (PFC2D) was adopted to carry out a discrete element modeling (DEM) for the mechanical behavior of heterogeneous rocks containing X-shaped fissures (two intersecting symmetric single fissures)...

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Main Authors: Ming Chen, Jian Liu, Zhengyong Xie, Jianjun Liu, Xunjian Hu, Bingyang Li, Yue Cen
Format: Article
Language:English
Published: Wiley 2020-01-01
Series:Geofluids
Online Access:http://dx.doi.org/10.1155/2020/8828199
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author Ming Chen
Jian Liu
Zhengyong Xie
Jianjun Liu
Xunjian Hu
Bingyang Li
Yue Cen
author_facet Ming Chen
Jian Liu
Zhengyong Xie
Jianjun Liu
Xunjian Hu
Bingyang Li
Yue Cen
author_sort Ming Chen
collection DOAJ
description Based on the experimental results of an intact rock specimen under uniaxial compression, particle flow code (PFC2D) was adopted to carry out a discrete element modeling (DEM) for the mechanical behavior of heterogeneous rocks containing X-shaped fissures (two intersecting symmetric single fissures) under uniaxial compression. The influences of β (the acute angle between two single fissures) and the direction angle α (the acute angle between the bisector of β and perpendicular to the loading direction) on the strength, deformation, energy, crack propagation, and ultimate failure mode were analyzed in detail. Numerical simulated results showed the following: (1) Due to the X-shaped fissures, not only the peak strength, elastic modulus, crack initiation stress, and damage stress were significantly reduced, and the reduced degree of the peak strength was obviously greater than that of the elastic modulus, but also the brittleness and energy were significantly weakened. (2) The peak strength and elastic modulus generally decreased with the increase of β and increased with the increase of α. Moreover, the change trends of crack initiation stress, damage stress, boundary energy, and total strain energy at the peak stress were consistent with the peak strength. (3) Regardless of the changes of α and β, models all firstly initiated wing cracks at the two tips of the single fissure with a larger inclination angle, and the crack initiation angle decreased with the increase of the inclination angle of the single fissure. (4) The fracture was dominated by tensile microcracks, and no microcracks were generated in a certain range of the X-shaped fissure center. The failure mode was mainly split along the axial direction, and the failure surface started from the tips of the fissure and extended to both ends of models. (5) The uniaxial compressive strength and elastic modulus increased exponentially with the increase of the homogeneity factor. When the homogeneity factor was small, the microcracks were more evenly distributed in the models; when the homogeneity factor was large, the microcracks were mainly concentrated at the tips of the fissure in the models. This study can provide some references for the correct understanding of the mechanical properties of rock masses containing X-shaped fissures.
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language English
publishDate 2020-01-01
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series Geofluids
spelling doaj-art-a52ca8381f0d43de8f4efa1500b8ad002025-02-03T01:28:34ZengWileyGeofluids1468-81151468-81232020-01-01202010.1155/2020/88281998828199Discrete Element Modeling on Mechanical Behavior of Heterogeneous Rock Containing X-Shaped Fissure under Uniaxial CompressionMing Chen0Jian Liu1Zhengyong Xie2Jianjun Liu3Xunjian Hu4Bingyang Li5Yue Cen6State Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, ChinaState Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, ChinaHubei Road and Bridge Group Tianxia Construction Co. Ltd., Wuhan 430000, ChinaState Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, ChinaState Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, ChinaState Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, ChinaState Key Laboratory of Geomechanics and Geotechnical Engineering, Institute of Rock and Soil Mechanics, Chinese Academy of Sciences, Wuhan 430071, ChinaBased on the experimental results of an intact rock specimen under uniaxial compression, particle flow code (PFC2D) was adopted to carry out a discrete element modeling (DEM) for the mechanical behavior of heterogeneous rocks containing X-shaped fissures (two intersecting symmetric single fissures) under uniaxial compression. The influences of β (the acute angle between two single fissures) and the direction angle α (the acute angle between the bisector of β and perpendicular to the loading direction) on the strength, deformation, energy, crack propagation, and ultimate failure mode were analyzed in detail. Numerical simulated results showed the following: (1) Due to the X-shaped fissures, not only the peak strength, elastic modulus, crack initiation stress, and damage stress were significantly reduced, and the reduced degree of the peak strength was obviously greater than that of the elastic modulus, but also the brittleness and energy were significantly weakened. (2) The peak strength and elastic modulus generally decreased with the increase of β and increased with the increase of α. Moreover, the change trends of crack initiation stress, damage stress, boundary energy, and total strain energy at the peak stress were consistent with the peak strength. (3) Regardless of the changes of α and β, models all firstly initiated wing cracks at the two tips of the single fissure with a larger inclination angle, and the crack initiation angle decreased with the increase of the inclination angle of the single fissure. (4) The fracture was dominated by tensile microcracks, and no microcracks were generated in a certain range of the X-shaped fissure center. The failure mode was mainly split along the axial direction, and the failure surface started from the tips of the fissure and extended to both ends of models. (5) The uniaxial compressive strength and elastic modulus increased exponentially with the increase of the homogeneity factor. When the homogeneity factor was small, the microcracks were more evenly distributed in the models; when the homogeneity factor was large, the microcracks were mainly concentrated at the tips of the fissure in the models. This study can provide some references for the correct understanding of the mechanical properties of rock masses containing X-shaped fissures.http://dx.doi.org/10.1155/2020/8828199
spellingShingle Ming Chen
Jian Liu
Zhengyong Xie
Jianjun Liu
Xunjian Hu
Bingyang Li
Yue Cen
Discrete Element Modeling on Mechanical Behavior of Heterogeneous Rock Containing X-Shaped Fissure under Uniaxial Compression
Geofluids
title Discrete Element Modeling on Mechanical Behavior of Heterogeneous Rock Containing X-Shaped Fissure under Uniaxial Compression
title_full Discrete Element Modeling on Mechanical Behavior of Heterogeneous Rock Containing X-Shaped Fissure under Uniaxial Compression
title_fullStr Discrete Element Modeling on Mechanical Behavior of Heterogeneous Rock Containing X-Shaped Fissure under Uniaxial Compression
title_full_unstemmed Discrete Element Modeling on Mechanical Behavior of Heterogeneous Rock Containing X-Shaped Fissure under Uniaxial Compression
title_short Discrete Element Modeling on Mechanical Behavior of Heterogeneous Rock Containing X-Shaped Fissure under Uniaxial Compression
title_sort discrete element modeling on mechanical behavior of heterogeneous rock containing x shaped fissure under uniaxial compression
url http://dx.doi.org/10.1155/2020/8828199
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