Article
Geochemistry & Geophysics
Rui Yang, Lv Jiakun, Bo Zhou, Depeng Ma
Summary: The mechanical response characteristics and occurrence mechanism of coal and rock under unloading conditions are crucial for evaluating the stability and control of rock excavation in engineering. Fractal characteristics of coal and rock acoustic emission time series were analyzed to predict the unloading failure of coal and rock. In addition, the HURST index was calculated to determine the unloading and fracture process of rock samples.
Article
Engineering, Geological
Xiangsheng Chen, Yinping Li, Lihong Tong, Daxin Geng, Zhikai Dong, Peiliang Yang
Summary: Experimental results suggest that the deformation and strength of rocks are heavily influenced by the damage suffered during loading. Traditional constitutive models fail to accurately describe the non-linear deformation behaviors of rocks. To address this limitation, a new elastoplastic damage constitutive model is proposed, taking into account the competition between damage and strain hardening or softening during rock compression. The model is validated through finite element programming and triaxial compression tests. Comparison with experimental data shows that the model effectively captures the stress-strain curves and damage-strain curves of rocks, particularly the phenomenon of softening, hardening, and residual strength. Parametric analysis reveals the impact of confining pressure, scale parameter, and shape parameter on rock damage. The results demonstrate that rock properties significantly affect strength and deformation, which are closely tied to stress-induced damage and strain characteristics.
ROCK MECHANICS AND ROCK ENGINEERING
(2023)
Article
Computer Science, Interdisciplinary Applications
Chao Zhang, Jianxin Fu, Yu Wang
Summary: The authors aimed to study the strength failure and cracking behavior of fractured rock under unilateral unloading. They found that prefabricated cracks and unilateral unloading conditions not only deteriorate the mechanical strength but also have significant differences in failure modes. Furthermore, the authors discovered that the model failure mode under unilateral loading conditions is obviously distinct from that in triaxial loading.
ENGINEERING COMPUTATIONS
(2023)
Article
Engineering, Civil
Yu Zhao, Daguo Quan, Chaolin Wang, Mingyang Teng, Jing Bi
Summary: The cracking behavior of internal cracks in rock-like materials was studied using camphor sheets to embed flaws. Results showed that internal flaws significantly reduced the peak strength and elastic modulus of samples, with varying failure modes at different flaw inclination angles. Experimental and simulated results were in good agreement, revealing the crack evolution mechanism in rock-like samples with internal flaws.
EUROPEAN JOURNAL OF ENVIRONMENTAL AND CIVIL ENGINEERING
(2022)
Article
Engineering, Mechanical
Miao Chen, Yuliang Zhang, Guangchao Zhang, Guanglei Zhou, Zihui Wang
Summary: An improved reaming hole pressure relief technology is proposed to overcome the disadvantages of traditional large-diameter hole pressure relief technology. Through a series of compression tests and numerical simulations, the pressure relief mechanism and the evolution of cracks are analyzed. The research results provide a foundation for evaluating the pressure relief effect through stress and fracture monitoring methods on the surrounding rock mass.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2023)
Article
Engineering, Geological
Zhuorui Wu, Tingting Xu, Chloe Arson
Summary: Understanding the damage propagation mechanisms in rock under true triaxial stress is crucial. This paper presents an enhanced version of the Discrete Equivalent Wing Crack Damage (DEWCD) model to predict damage in true triaxial compression tests. The model successfully captures the deformation and damage differences in different loading directions and accurately predicts the effects of intermediate principal stress on deformation and damage.
ROCK MECHANICS AND ROCK ENGINEERING
(2022)
Article
Chemistry, Physical
Yifan Chen, Hang Lin, Shijie Xie, Rihong Cao, Shuwei Sun, Wenhua Zha, Yixian Wang, Yanlin Zhao, Huihua Hu
Summary: In this study, a piecewise constitutive model was proposed to simulate the nonlinear fracture compaction deformation in the whole process of rock failure. The model consisted of a fracture compaction empirical model and a damage statistical constitutive model. The parameters of the models were calculated based on the geometrical characteristics of the axial stress-strain curve to ensure continuity and smoothness at the curve intersection. The models were validated using uniaxial compression test data and triaxial compression test data, showing great consistency with the experimental results, particularly in the pre-peak stage.
Article
Materials Science, Multidisciplinary
Zhi Zheng, Jiaju Zhou, Junhong Li, Honghui Tao, Xiaofeng Han, Hongyu Xu, Qiang Zhang
Summary: A three-dimensional mechanical model suitable for stability analysis of deep surrounding rock was studied, and a series of tests were conducted to analyze the strength and deformation characteristics of two rocks under different stress conditions. A new statistical damage constitutive model was proposed, which can well simulate the deformation and intermediate principal stress effect of rock under true triaxial stress conditions.
INTERNATIONAL JOURNAL OF DAMAGE MECHANICS
(2023)
Article
Materials Science, Multidisciplinary
Yan-Shuang Yang, Wei Cheng, Zhan-Rong Zhang, Hao-Yuan Tian, Kai-Yue Li, Cai-Ping Huang
Summary: This study established a numerical biaxial compression model using PFC2D to analyze the development of micro-cracks, energy dissipation and damage evolution during tests on Jinping marble. The research found that both crack number and total energy dissipation increased with confining pressures, and the energy-based damage variable showed a closer fit to axial strain in the final failure period.
FRONTIERS IN MATERIALS
(2021)
Article
Chemistry, Multidisciplinary
Lide Wei, Zhinan Lin, Haifeng Long, Qiongyao Ye
Summary: This study investigates the mechanical properties and permeability characteristics of sandstone during damage evolution under hydromechanical condition. The results show that the failure mode and permeability of sandstone vary with different working conditions. Additionally, a Weibull distribution formula is used to analyze the evolution of fracture damage and determine the relationship between permeability and damage variables.
APPLIED SCIENCES-BASEL
(2023)
Article
Engineering, Geological
Xunjian Hu, Junjie Shentu, Ni Xie, Yujie Huang, Gang Lei, Haibo Hu, Panpan Guo, Xiaonan Gong
Summary: Five machine learning techniques were used to predict the strength of rocks after high-temperature treatment. The results showed that the BPNN model had the best prediction performance.
JOURNAL OF ROCK MECHANICS AND GEOTECHNICAL ENGINEERING
(2023)
Article
Engineering, Mechanical
Zhi-Jin Dong, Sheng-Qi Yang, Bo-Wen Sun, Wen-Ling Tian, Yan-Hua Huang
Summary: In this study, a three-dimensional grain-based model was used to simulate the triaxial compression of fissured granite specimens under different confining pressures. The results showed that fissured granite has smaller mechanical properties compared to intact granite, and the mechanical properties increase with the increase of fracture angle. As axial stress increases, cracks emerge from the crack apices and propagate towards the ends of the specimen. The main cracks occur at the interfacial locations where large relative displacements occur between the particles. The distribution of cracks is influenced by both the confining pressure and the fissure angle.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2022)
Article
Engineering, Geological
Jun Zhao, Xia-Ting Feng, Chengxiang Yang, Yangyi Zhou, Yan Zhang
Summary: Crack propagation in hard rocks is influenced by applied stress and mineral composition, with high axial stress causing cracks to develop over time. The determination of damage stress through short-term tests can be efficiently utilized for long-term strength analysis, despite slight differences between the values obtained from short-term and long-term tests.
ROCK MECHANICS AND ROCK ENGINEERING
(2021)
Article
Engineering, Geological
Feiyan Wang, Xia-Ting Feng, Yangyi Zhou, Xiaojun Yu
Summary: The study investigates the effect of cementation and intermediate principal stress on the failure mechanism of clastic rock under true triaxial stress. The results show that the deformation and failure characteristics of clastic rock are closely related to the cementation type and intermediate principal stress. This study confirms the feasibility of high-speed camera technology in true triaxial testing and has important implications for understanding the disaster mechanism of deep tunnels in weak rocks.
JOURNAL OF ROCK MECHANICS AND GEOTECHNICAL ENGINEERING
(2023)
Article
Engineering, Geological
Weijing Xiao, Guo Yu, Haitao Li, Weiyun Zhan, Dongming Zhang
Summary: The experimental results show that the stress-strain curve, Young's modulus, and crack volume strain of sandstone samples exhibit unique characteristics during cyclic loading and unloading after high-temperature treatment. The dissipation energy of sandstone samples increases significantly after high-temperature treatment compared to samples treated at lower temperatures.
ENGINEERING GEOLOGY
(2021)
Article
Engineering, Geological
Sheng-Qi Yang, Yan-Hua Huang, Wen-Ling Tian
ROCK MECHANICS AND ROCK ENGINEERING
(2021)
Article
Engineering, Geological
Sheng-Qi Yang, Peng-Fei Yin, Shuai-Bo Xu
Summary: The research investigated the gas conductivity of shale rock with different bedding directions and fracture surfaces. It found that the permeability of intact and fractured shale specimens decreased exponentially with increasing effective stress. A new model was proposed to describe the anisotropy of rock permeability characteristics, and the relationship between equivalent permeability, fracture permeability, and effective stress was derived for shale specimens containing fractures.
ROCK MECHANICS AND ROCK ENGINEERING
(2021)
Article
Energy & Fuels
Sheng-Qi Yang, Jin-Zhou Tang, Derek Elsworth
Summary: This study explores the potential of utilizing underground coal gasification cavities for carbon capture and sequestration, and investigates the key issue of thermal influence on creep properties and permeability evolution during UCG-CCS operation. The research found that thermal-induced cracks are initiated at temperatures of 500 degrees C, with subsequent strength reduction occurring at 750 degrees C. Additionally, rock specimens subjected to higher pre-treatment temperatures exhibit higher permeabilities and greater damage tolerance.
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
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
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)
Article
Engineering, Geological
Jin-Zhou Tang, Sheng-Qi Yang, Derek Elsworth, Yan Tao
Summary: The study compares physical experiments with a three-dimensional bonded-particle discrete element model, finding that confining stress significantly strengthens the jointed sandstone and failure is controlled by the threshold angle of about 40 degrees. The 3D numerical approach replicates the deformation history of jointed rock samples accurately, providing a viable model for emulating the mechanical behavior of jointed rocks with high fidelity.
ROCK MECHANICS AND ROCK ENGINEERING
(2021)
