Article
Engineering, Environmental
Dan Huang, Wen Tang, Xiao-qing Li
Summary: In this study, the relationships between nonpersistent joints and intact rock bridges in rock masses were explored using discrete fracture network (DFN) technology and synthetic rock mass (SRM) technology. The effects of geometrical parameters on the mechanical properties and failure mechanism of the models were studied. The failure process of the nonpersistent jointed rock mass under uniaxial compression was investigated, and six failure modes were predicted. The damage constitutive model fit well with the stress-strain curve and was suitable for brittle failure of a jointed rock mass.
BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT
(2023)
Article
Engineering, Geological
Mostafa Asadizadeh, Mahdi Moosavi, Mohammad Farouq Hossaini, Ahmadreza Hedayat, Taghi Sherizadeh, Hossein Masoumi
Summary: Characterizing the mechanical behavior of jointed rocks is crucial for understanding the behavior of structures in rock masses. In this study, synthetic jointed rocks with nonpersistent rough joints were numerically investigated under uniaxial compressive and shear loadings. The results showed that the joint roughness coefficient and normal stress had a more pronounced effect on the shear strength, while the bridge angle and length had a smaller impact. Moreover, an increase in joint inclination led to a decrease in deformation modulus, while an increase in JRC resulted in increased strength of the jointed samples.
INTERNATIONAL JOURNAL OF GEOMECHANICS
(2023)
Article
Engineering, Geological
Mostafa Asadizadeh, Mahdi Moosavi, Mohammad Farouq Hossaini, Ahmadreza Hedayat, Taghi Sherizadeh, Hossein Masoumi
Summary: This study investigated the mechanical behavior of synthetic jointed rocks with nonpersistent rough joints under uniaxial compressive and shear loadings. The effects of bridge angle, length, joint roughness coefficient, and normal stress on shear strength and cracking behavior were examined numerically. The results showed that the joint roughness coefficient and normal stress had a more significant impact on shear strength, while the bridge angle and length had a smaller effect. Additionally, an increase in joint inclination reduced the deformation modulus, and a higher joint roughness coefficient increased the strength of jointed samples.
INTERNATIONAL JOURNAL OF GEOMECHANICS
(2023)
Article
Engineering, Civil
Yongning Wu, Yang Zhao, Peng Tang, Wenhai Wang, Lishuai Jiang
Summary: By introducing the technology of synthetic rock mass, the influence of nonpersistent joint network parameters on the mechanical properties and failure modes of jointed rock masses is studied. The compressive strength and discreteness of the rock mass change as the size of the joints in the rock mass increases. The location and density of the joints greatly affect the failure mode and displacement degree of the jointed rock mass.
GEOMECHANICS AND ENGINEERING
(2022)
Article
Environmental Sciences
Yuan Wei, Liu Sifan, Tan Hanhua, Niu Jiandong, Jiang Zhiling, Li Xilai, Peng Shu, Xue Yanyu, Wang Wei, Sun Xiaoyun
Summary: A new method for calculating the JRC of rock joints was proposed, which accurately quantified the JRC of two-dimensional joints. The accuracy of the JRC greatly depends on the sampling interval along the joint profile, with a recommended length of no greater than (1/120) L.
ENVIRONMENTAL EARTH SCIENCES
(2021)
Article
Engineering, Geological
S. C. Wang, X. X. Yang, W. T. Li, W. G. Qiao
Summary: This study conducted direct shear tests on rock specimens with two parallel incipient joints through a newly proposed method to better understand the influence of rock bridges. The failure process of nonpersistent closed rough joints was divided into seven stages, which were successfully verified using PFC2D. The roughness of the joint surface altered the mobilization pattern and the rock bridge weakened the transmission of shear stress, causing unsynchronized mobilization displacements of the joints on either side of the rock bridge. The rock bridge reduced the peak displacement of the joint surface by altering the degree of wear, while increasing the peak displacement of the rock bridge due to the unsynchronized mobilization of the joint surface, thereby altering the failure behavior of the rock joints.
ROCK MECHANICS AND ROCK ENGINEERING
(2023)
Article
Engineering, Environmental
Chang'an Qin, Guoqing Chen, Tianbin Li, Kaiyun Hu, Guowei Zhang
Summary: The shear behaviors of sandstone specimens containing nonpersistent joints are investigated through a standard direct shear test under unloading normal stress, and the results are compared with conventional direct shear tests. The overall cracking behavior of the rock bridge without a precursor is observed under unloading conditions, while segmented progressive coalescence is observed under loading conditions. The cohesion and internal friction angle are affected by the continuity factor, with smaller cohesion and larger internal friction angle under unloading conditions and the opposite relationship under loading conditions. The evolution of shear strength parameter affected by the continuity factor is revealed through analysis of the damage degree of the rock bridge per unit length. The failure plane characteristics reflect basement sliding behavior and striated scratch-like gullies are caused by tensile damage.
BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT
(2023)
Article
Computer Science, Interdisciplinary Applications
Yiguo Xue, Xudong Jiang, Fanmeng Kong, Zhiqiang Li, Huimin Gong, Fan Yang, Hong Chen
Summary: This study explores the characteristics of rock fragmentation in blasting scenarios for jointed rock mass of underground space by creating bonded particle models with discontinuities. The study found that different types of discontinuities have different effects on crack propagation and rock fragmentation.
SIMULATION MODELLING PRACTICE AND THEORY
(2022)
Article
Engineering, Geological
Sayedalireza Fereshtenejad, Jineon Kim, Jae-Joon Song
Summary: This paper introduces an empirical equation to evaluate the shear strength of rock mass with nonpersistent joints and presents a novel specimen preparation method. The effects of influential parameters on shear strength were studied through experimental work, culminating in an empirical equation for calculating shear strength.
INTERNATIONAL JOURNAL OF GEOMECHANICS
(2021)
Article
Engineering, Geological
Daping Tai, Shengwen Qi, Bowen Zheng, Chonglang Wang, Songfeng Guo, Guangming Luo
Summary: In this study, the effects of joint row number and inclination on the stress-strain characteristics and failure mode of rock were investigated using numerical models and laboratory direct shear tests. The results showed that joints significantly increased post-peak energy dissipation but had little effect on energy proportion before the peak.
JOURNAL OF ROCK MECHANICS AND GEOTECHNICAL ENGINEERING
(2023)
Article
Engineering, Geological
Jintong Zhang, Mamoru Kikumoto, Hideaki Yasuhara, Sho Ogata, Kiyoshi Kishida
Summary: The normal compression and shear behavior of rock joints were investigated, and a mechanical model was proposed to incorporate the effects of closure variation and initial state. The model was validated by experimental results.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2022)
Article
Mechanics
Xizhuo Chen, Haitao Yu
Summary: In this study, a novel micropolar peridynamic model is proposed to simulate the fracture behaviors of rock masses with arbitrary joints. The rock masses are discretized into material points linked through ordinary and joint bonds. Peridynamic parameters are introduced to ensure consistency with continuum mechanics. A stress-based failure criterion is proposed to describe dynamic fracture of jointed rocks. The model is verified using experimental observations and numerical examples demonstrate its accuracy in capturing wave transmission and crack development in rocks with different joint sets. The influence of joint geometry on failure characteristics is also investigated.
ENGINEERING FRACTURE MECHANICS
(2023)
Article
Engineering, Environmental
Yakun Wang, Xuxu Yang, Weiteng Li, Weiguo Qiao
Summary: Anchored bolts are an effective measure to support rock masses, however, their effects on rock mass containing nonpersistent joints have rarely been investigated. In this study, experimental research was carried out to examine the effect of anchored bolts on failure and strength behavior of nonpersistent jointed rock model. The results showed that anchored bolts mainly increased the strength of jointed samples with intermediate dip angles, and provided lateral constraints and pin effect.
BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT
(2023)
Article
Geochemistry & Geophysics
Qian Yin, Hongwen Jing, Tantan Zhu, Lizhou Wu, Haijian Su, Liyuan Yu
Summary: This study analyzes the spatiotemporal evolution characteristics of seepage through a large-scale rock mass containing a filling joint. It was found that migration of fillings can lead to a water inrush phenomenon. The influences of factors such as joint permeability, matrix permeability, and inlet water pressure on seepage evolution were investigated, showing that pore water pressure and flow velocity increase with these factors.
Article
Environmental Sciences
Changyu Jin, Junyu Liang, Jianxin Cui, Qiang Wang
Summary: Rock mass classification is crucial for assessing rock mass quality and designing geotechnical engineering. However, traditional methods lack accuracy. This study proposes a method using precise joint description for rock mass classification, which determines weights based on cloud model theory and evaluates rock mass quality through a comprehensive assessment approach.
ENVIRONMENTAL EARTH SCIENCES
(2023)
Article
Engineering, Geological
Qiang Feng, Jichao Jin, Shuang Zhang, Weiwei Liu, Xuxu Yang, Weiteng Li
Summary: The study found that with an increasing number of freeze-thaw cycles, the elastic modulus, peak strength and wave velocity of yellow sandstones gradually decrease, while the peak strain and porosity increase. An energy evolution law with different freeze-thaw cycles was analyzed, a freeze-thaw damage model was established, and a functional relationship between mesoscopic parameters and freeze-thaw cycles was formulated.
ROCK MECHANICS AND ROCK ENGINEERING
(2022)
Article
Engineering, Environmental
Zhennan Zhu, Shengqi Yang, Pathegama Gamage Ranjith, Hong Tian, Guosheng Jiang, Bin Dou
Summary: Understanding the deformation and failure characteristics of rocks under thermal treatment is crucial in deep rock engineering. A statistical model for rock deformation was established, considering the temperature effect, and the model showed good agreement with experimental data. The improved model captured the void compaction stage of granite after high temperature better than the classic damage model.
BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT
(2022)
Article
Engineering, Geological
Sheng-Qi Yang, Jin-Zhou Tang, Su-Sheng Wang, Dian-Sen Yang, Wen-Tang Zheng
Summary: The objective of this work is to investigate the creep damage mechanism of granite from a nuclear power station. A series of multi-step loading and unloading cycles creep tests of granite were carried out under different confining pressures. The results show that the short-term strength, crack damage threshold, and Young's modulus all increased with the increasing of confining pressure. An exponential function is proposed, which can well describe the relationship between the visco-plastic strain and stress ratio. The damage mechanism of the failed granite specimens is analyzed using an X-ray micro-CT scanning system. A time-dependent damage model is proposed to quantitatively characterize the creep damage and deformation behaviors of granite.
ROCK MECHANICS AND ROCK ENGINEERING
(2022)
Article
Engineering, Mechanical
Bo-Wen Sun, Sheng-Qi Yang, Jie Xu, Peng-Fei Yin
Summary: Based on the discrete element method, this study established a numerical model to investigate the macro- and meso-mechanical properties of bedded shale under different unloading paths and bedding inclinations. The results revealed that bedding inclination has a significant influence on mechanical parameters and failure modes under unloading. The peak strength and ultimate bearing capacity showed a U-shaped trend, with maximum values observed at beta = 0 degrees or beta = 90 degrees and minimum values at beta = 30 degrees or beta = 45 degrees. The failure modes varied depending on the bedding inclination, with splitting damage observed at lower initial confining pressure for beta = 0 degrees and shear-slip damage observed for beta = 15-45 degrees. Shale specimens with beta = 60-90 degrees exhibited conjugate shear damage intersecting with the weak surface. The damage caused by unloading and increasing axial stress was greater than that caused by unloading and constant axial strain. The effects of beta = 0 degrees and 90 degrees on microcracking and stress distribution within the specimen were significantly smaller compared to other bedding inclinations.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2022)
Article
Engineering, Geological
Hong-Wen Jing, Xu-Xu Yang, Mao-Lin Zhang
Summary: Large deformation of anchored rock masses or pull-out failure of anchor bolts often occurs in tunneling practices. The existence of incipient joints in rock masses might account for the failure of anchor bolts. The present study utilized numerical modeling experiments to investigate the effects of anchor bolts on rock mass stability. The findings demonstrate that anchor bolts increase the strength of jointed rock blocks and reduce the nonuniformity of stress distribution, thereby preventing tendentious failure along incipient joint planes.
GEOTECHNICAL AND GEOLOGICAL ENGINEERING
(2023)
Article
Computer Science, Interdisciplinary Applications
Sheng-Qi Yang, Ye Li, Guo-Wei Ma, Bo-Wen Sun, Jing Yang, Jie Xu, Yong-Hao Dai
Summary: The dynamic compression experiments were conducted on granite specimens after high-temperature treatments, and the fragmentation characteristics were evaluated using fractal dimension and average fragment size. The results showed that the physical properties of the granite were closely related to the temperature, and microcracking occurred at 900 degrees Celsius. The fractal dimension and average fragmentation size were found to be inversely linearly related, and the crack propagation during dynamic compression followed a pattern of initial appearance on the surface and gradual propagation to the interior.
COMPUTERS AND GEOTECHNICS
(2023)
Article
Engineering, Geological
Zhen Yang, Sheng-Qi Yang, Wenbo Zheng, Dwayne D. Tannant
Summary: This paper presents an improved multi-layer computational method based on fully coupled thermal-mechanical OSB-PD for simulating fracturing in granite under coupled thermal-hydraulic effects. The method includes four computational layers and was verified through simulation and comparison with experimental results. It successfully predicts the behavior of granite specimens subjected to HTHP hydraulic fracturing tests.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2022)
Article
Engineering, Geological
S. C. Wang, X. X. Yang, W. T. Li, W. G. Qiao
Summary: This study conducted direct shear tests on rock specimens with two parallel incipient joints through a newly proposed method to better understand the influence of rock bridges. The failure process of nonpersistent closed rough joints was divided into seven stages, which were successfully verified using PFC2D. The roughness of the joint surface altered the mobilization pattern and the rock bridge weakened the transmission of shear stress, causing unsynchronized mobilization displacements of the joints on either side of the rock bridge. The rock bridge reduced the peak displacement of the joint surface by altering the degree of wear, while increasing the peak displacement of the rock bridge due to the unsynchronized mobilization of the joint surface, thereby altering the failure behavior of the rock joints.
ROCK MECHANICS AND ROCK ENGINEERING
(2023)
Article
Engineering, Environmental
Yakun Wang, Xuxu Yang, Weiteng Li, Weiguo Qiao
Summary: Anchored bolts are an effective measure to support rock masses, however, their effects on rock mass containing nonpersistent joints have rarely been investigated. In this study, experimental research was carried out to examine the effect of anchored bolts on failure and strength behavior of nonpersistent jointed rock model. The results showed that anchored bolts mainly increased the strength of jointed samples with intermediate dip angles, and provided lateral constraints and pin effect.
BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT
(2023)
Article
Green & Sustainable Science & Technology
Jinzhou Tang, Shengqi Yang, Ke Yang, Wenling Tian, Guangjian Liu, Minke Duan
Summary: A new thermal damage numerical model was proposed to analyze the cracks on pre-cracked red sandstone after thermal treatment. The thermal damage value, obtained by extracting the thermal crack area from SEM images, served as an indicator of the degree of thermal damage. By replacing the flat-joint model with the smooth-joint model based on the thermal damage value, the mechanical behavior and failure patterns of sandstone were accurately simulated. In addition, the critical temperature for strength reduction was found to be 750 degrees C.
Article
Energy & Fuels
Sheng-Qi Yang, Shuai-Bo Xu, Zhen Liu, Bo-Wen Sun, Peng-Fei Yin
Summary: In this study, stress-strain curves of sandstone soaked in 5% NaCl and 5% K2SO4 solutions were obtained under different loading and unloading paths. The results showed that sandstone soaked in 5% NaCl exhibited greater unloading capacity compared to sandstone soaked in 5% K2SO4. The strain change rate during the unloading process was higher for sandstone soaked in 5% K2SO4. The deformation modulus and Poisson's ratio of sandstone soaked in 5% NaCl were greater and less than those of sandstone soaked in 5% K2SO4, respectively. The total energy absorbed by sandstone soaked in 5% NaCl was always lower than that soaked in 5% K2SO4.
GEOMECHANICS AND GEOPHYSICS FOR GEO-ENERGY AND GEO-RESOURCES
(2023)
Article
Energy & Fuels
Pengfei Yin, Shengqi Yang, Feng Gao, Wenling Tian
Summary: Drilling wellbores in shale reservoirs can lead to instability due to the stress release and change in stress equilibrium. This study investigated the strength, failure, strain energy evolution, and micro-crack damage of shale specimens under confining pressure unloading conditions. The research revealed that confining pressure unloading induces greater plastic deformation, more micro-crack damage, and a more complex failure pattern.
Editorial Material
Energy & Fuels
Chun Zhu, Shengqi Yang, Yuanyuan Pu, Lijun Sun, Min Wang, Kun Du
Article
Engineering, Geological
Yu Song, Sheng-Qi Yang, Ke-Sheng Li, Peng-Fei Yin, Peng-Zhi Pan
Summary: This study establishes a three-dimensional numerical model to investigate the failure behavior of transversely isotropic rock formations, with a focus on the effects of confining pressure and laminar inclination angle. The results of the numerical simulations show that the confining pressure and laminar angle significantly influence the internal crack evolution patterns of the specimen.
ROCK MECHANICS AND ROCK ENGINEERING
(2023)
Article
Metallurgy & Metallurgical Engineering
Sheng-qi Yang, Jin-peng Dong, Jing Yang, Zhen Yang, Yan-hua Huang
Summary: Fissures play a significant role in predicting the unstable failure of rock mass engineering. In this research, the effect of bridge angle and confining pressure on the mechanical behavior of granite specimens containing pre-existing fissures was evaluated. The study found that confining pressure affects the strength, deformation characteristics, and crack evolution behavior of the granite specimens.
JOURNAL OF CENTRAL SOUTH UNIVERSITY
(2022)
