Article
Engineering, Geological
Kai Zhao, Hongling Ma, Chunhe Yang, Xiangsheng Chen, Yibiao Liu, Xiaopeng Liang, Rui Cai
Summary: Research shows that the deformation of rock salt under creep-fatigue loading consists of initial, steady, and accelerated phases. The proposed damage accumulation model matches well with test data and accurately describes the evolution of damage as stress amplitudes and dwell times change.
ROCK MECHANICS AND ROCK ENGINEERING
(2021)
Article
Chemistry, Multidisciplinary
Zhengshuai Liu, Longyong Shu, Nannan Zhu, Zhonggang Huo, Zhongxue Sun
Summary: This study investigated the time-frequency characteristics and evolution of acoustic emission (AE) signals during deformed coal failure. The damage process of coal was divided into three stages based on the volume strain and AE event rate. The distribution and evolution of AE waveform time-frequency properties were analyzed, and the relationship between different time-frequency parameters and loading stress was discussed. The research provides theoretical guidance for the early warning of coal failure.
Article
Metallurgy & Metallurgical Engineering
Jian-feng Liu, Chun-ping Wang, Lu Wang, Li-na Ran, Chao-fu Deng
Summary: The tensile strength of rock salt is an important parameter in salt cavern gas storage project. This study discusses the alternative methods to obtain the tensile strength, including direct tensile test, Brazilian test with simplified ISRM standard, Brazilian test with China standard, and three-point-bending test. The results show that the testing method affects the tensile strength and acoustic emission characteristics of rock salt. The indirect tensile strength determined by three-point-bending test is closer to the direct tensile strength, suggesting that the three-point-bending test can be a good option for obtaining the tensile strength of rock salt.
JOURNAL OF CENTRAL SOUTH UNIVERSITY
(2023)
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
Energy & Fuels
Jie Liu, Fei Wu, Quanle Zou, Jie Chen, Song Ren, Chuang Zhang
Summary: This study analyzes the instantaneous elastic strain, visco-elastic and visco-plastic strain components from experimental data, introducing a damage coefficient to describe nonlinear strain in the accelerating creep stage. A new variable-order fractional derivative model with damage is proposed, showing that the coefficient of damage plays a more important role than the fractional order in the nonlinear rheological behavior of salt rock. The results of the new model are in better agreement with experimental data than those of other rheological models, providing a more precise description of the full stages of creep.
GEOMECHANICS AND GEOPHYSICS FOR GEO-ENERGY AND GEO-RESOURCES
(2021)
Article
Mechanics
Kai Zhao, Hongling Ma, Yinping Li, Peng Li, Zhikai Dong, Xin Liu, Hongwu Yin, Chunhe Yang, Xiangsheng Chen
Summary: This study conducted multilevel cyclic loading tests on rock salt to investigate the deformation and damage evolution. The results showed that deformation generally increased with loading stress levels, and the damage variable gradually increased with the loading level. The damage accumulation at each loading level generally exhibited two stages of rapid increase followed by stable increase.
ENGINEERING FRACTURE MECHANICS
(2022)
Article
Engineering, Geological
Fei Wu, Xuhui Zhou, Peng Ying, Cunbao Li, Zheming Zhu, Jie Chen
Summary: Based on the Riemann-Liouville type fractional-order calculus operator theory and acoustic emission (AE) theory, this paper improves the traditional creep model and proposes a fractional-order derivative-based creep model for salt rock. The model is validated by uniaxial creep damage tests on rock salt specimens, and it shows a good agreement with the experimental results, accurately predicting the time point when salt rock enters the accelerated creep stage. The proposed model can simulate the whole process of rock creep well and has practical application value.
ROCK MECHANICS AND ROCK ENGINEERING
(2022)
Article
Engineering, Multidisciplinary
Zilong Zhou, Congcong Zhao, Yinghua Huang
Summary: Nonlinear analysis is a powerful tool for studying instability and preventing disasters in rock mass engineering. A new method based on fractal theory is proposed to determine the fractal characteristics of the failure process using time series analysis. The time series analysis of fracture sources in the failure process of rock mass shows notable fractal characteristics. The advantage of this method is the better identification and classification of damage compared with traditional natural sequence frequency distribution.
Article
Engineering, Mechanical
Yu Wang, Mingqi Yan, Weibin Song
Summary: This study aims to investigate the influence of cyclic stress amplitude (CSA) on the macro-meso failure characteristics of deeply buried rock during the process of confining pressure unloading. Experimental results demonstrate that the deterioration of rock structure is affected by the disturbed stress amplitude. The lateral expansion caused by confining pressure unloading has a significant impact on rock volumetric deformation, damage propagation, and failure characteristics. Additionally, a damage evolution model is proposed to describe the progressive damage evolution pattern, which can be expressed using the irreversible lateral strain. CT images reveal the complexity of the crack network, which decreases with increasing CSA. Furthermore, the final volumetric deformation depends not only on the stimulated crack pattern but also on the failure modes, with specimens exhibiting pure shear failure mode showing the largest volumetric deformation.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2023)
Article
Energy & Fuels
Zhehao Zhang, Baisheng Nie
Summary: The fracturing experiment of hard rock was performed using a self-designed high-voltage electrical pulse (HVEP) equipment. By increasing the discharge energy, the capacitance was increased from 20 to 500 μF at a discharge voltage of 10 kV. The rock was successfully fractured under the discharge conditions of 10 kV and 500 μF. Images of the fracture process were recorded, and the action characteristics of HVEP were analyzed through current waveforms, strain curves, and vibration curves at different discharge energies. Increasing the capacitance enhances the current peak, strain peak, and peak particle velocity, leading to a stronger cracking effect. However, the discharge effect of HVEP does not always increase with capacitance. The appearance of cracks in the rock results in obvious instability characteristics, including prolongation of peak strain time and acceleration of vibration decay rate.
Article
Physics, Multidisciplinary
Giovani E. Morales-Hernandez, Juan C. Castellanos, Jose L. Romero, Andrei B. Klimov
Summary: In this study, the semi-classical limit of the generalized SO(3) map is applied to represent variable-spin systems in a four-dimensional symplectic manifold, and the evolution terms of effective classical dynamics are approximated on T*S-2. By quantizing one of the classical variables using the asymptotic form of the star-product, a discretized version of the Truncated Wigner Approximation (TWA) is introduced. The analysis of two emblematic examples of quantum dynamics (rotor in an external field and two coupled spins) compares the results of exact, continuous, and discretized versions of TWA.
Article
Chemistry, Multidisciplinary
Shaohua Gao, Huajun Meng, Yunfeng Wu, Xuebing Wang, Yu Wang, Jihuan Wu, Peng Wang
Summary: This study investigated the fracture evolution characteristics of argillaceous shale under increasing-amplitude loading. Results showed that strength, deformation, and fatigue life increased with frequency, and the hysteresis curve morphology changed regularly with time. Cumulative damage at the sudden stress amplitude increase location exceeded that at the fatigue loading stage, and the loading frequency impacted AE count and energy. This research developed a cumulative fatigue damage model to understand the frequency effect on fracture behavior and predict the lifespan of rock structures.
APPLIED SCIENCES-BASEL
(2023)
Article
Mechanics
Zesheng Zang, Zhonghui Li, Yue Niu, Shan Yin
Summary: This study conducted experiments and recorded signals to investigate the fracture behavior and damage evolution characteristics of coal samples. The results showed that as loading proceeds, the stress, electric potential (EP), and acoustic emission (AE) values increase, and EP and AE signals are excited when stress drops. The fracture behavior of coal samples is altered by flaw inclination, and the destruction mode becomes increasingly complicated. The damage evolution characteristics of coal samples can be evaluated and analyzed by defining the coefficient of variation (CV value) of EP and the b value of AE.
ENGINEERING FRACTURE MECHANICS
(2024)
Review
Construction & Building Technology
Qiang Zhang, Zhanping Song, Junbao Wang, Yuwei Zhang, Tong Wang
Summary: Salt rock is considered internationally as the ideal medium for underground storage of energy and disposal of radioactive waste due to its advantages of low porosity, low permeability, high ductility, and excellent capacities for creep and damage self-healing. The creep properties of salt rock are crucial for the long-term stability and safety of underground storage caverns, with research priorities including permeability variation under temperature and stress coupling, damage mechanisms under creep-fatigue interaction, and establishment of a creep damage constitutive model.
ADVANCES IN CIVIL ENGINEERING
(2021)
Article
Engineering, Mechanical
Yu Wang, Zhaohui Cao, Tianqiao Mao, Peng Li, Meifeng Cai
Summary: Through cyclic triaxial fatigue loading experiments on deeply buried rock, it is found that the deformation, energy evolution, and failure modes of the rock are all influenced by the cyclic stress amplitude. The strain energy of the rock increases with increasing cyclic stress amplitude, especially during the unloading stage. It is also found that shear cracks require much more energy to be induced than tensile cracks.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2023)
Article
Engineering, Civil
Chunping Wang, Jianfeng Liu, Liang Chen, Jian Liu, Lu Wang
Summary: This study conducted a series of tests on integrated and unloading-cracked rock specimens to investigate their properties and behaviors. The results revealed that saturation has an effect on the strength and deformation of rocks. Additionally, the acoustic emission (AE) signals were found to be more sensitive in monitoring creep failure.
EUROPEAN JOURNAL OF ENVIRONMENTAL AND CIVIL ENGINEERING
(2022)
Article
Materials Science, Multidisciplinary
Cheng Lyu, Jianfeng Liu, Yi Ren, Chao Liang, Qiangxing Zhang
Summary: This study investigated the long-term creep characteristics of bedded rocks in salt storage caverns, finding that the combined body exhibited different creep properties compared to pure rocksalt and mudstone. It was observed that the mudstone layer had lower strain than the rocksalt layer, and as the height ratio of mudstone increased, the creep strain decreased while the creep rate increased. A new nonlinear creep-damage constitutive model was proposed and shown to be more consistent with experimental data compared to classical creep models.
INTERNATIONAL JOURNAL OF DAMAGE MECHANICS
(2022)
Article
Energy & Fuels
Rongchen Tong, Hejuan Liu, Jianfeng Liu, Yingkun Shi, Lihuan Xie, Shengnan Ban
Summary: This study investigates the effects of chemical stimulation on the porosity and permeability of granite matrix. It is found that chemical corrosion using mud acid solution increases the number of micropores in the granite and improves the efficiency of heat extraction. Additionally, acidic treatment decreases the peak stress and elastic modulus of the granite, indicating a change in its mechanical characteristics.
Article
Energy & Fuels
Qiangxing Zhang, Jianfeng Liu, Zhide Wu, Lu Wang, Chaofu Deng, Yin Zeng
Summary: The demand for energy storage and the construction of underground gas storage facilities have been widely recognized. This study conducted comprehensive tests on limestone regarding gas permeability and triaxial compression under different stress conditions using a hydro-mechanical (HM) coupling testing platform in the laboratory. The results showed that porosity and initial permeability decreased with increasing confining pressure, and the permeability-axial strain curves of limestone exhibited different evolution laws related to crack volume deformation characteristics.
INTERNATIONAL JOURNAL OF OIL GAS AND COAL TECHNOLOGY
(2022)
Article
Energy & Fuels
Leiyu Gao, Xiangchao Shi, Jianfeng Liu, Xiuping Chen
Summary: This study analyzes wellbore stability in fractured formations using the discrete element method and proposes a novel modeling method for fractures. The findings suggest that high dip fractures are the main cause of wellbore instability, and drilling fluid density has minimal effects on wellbore stability.
JOURNAL OF NATURAL GAS SCIENCE AND ENGINEERING
(2022)
Article
Engineering, Geological
Chengxing Zhao, Jianfeng Liu, Cheng Lyu, Weizhi Chen, Xiangyang Li, Zhicheng Li
Summary: The study reveals that gas pressure and confining pressure significantly affect the mechanical properties and permeability of limestone from coal measures strata, highlighting the need to pay attention to the unstable crack propagation stage during tunnel construction. The possibility of gas leakage during the compaction process should be noted, and the closure and propagation of microcracks play a crucial role in the stress variation process and permeability of limestone samples.
ENGINEERING GEOLOGY
(2022)
Article
Chemistry, Multidisciplinary
Yanfeng Zhang, Yongbo Tie, Luqi Wang, Jianfeng Liu
Summary: Glacial till is a special soil in alpine mountainous areas that often leads to geohazards. This study focused on the meso-structure and micro-structure of glacial till in the Moxi River Basin, Sichuan Province. CT scanning and scanning electron microscopy were used to analyze the porosity, particle shape, directivity, and structural unit. The findings provide scientific basis for construction projects and disaster prevention in alpine mountainous areas.
APPLIED SCIENCES-BASEL
(2022)
Article
Geosciences, Multidisciplinary
Huaimin Wang, Cunhui Fan, Yi Fang, Shengxian Zhao, Xiangchao Shi, Jianfeng Liu, Hongfeng Yang, Jun Hu, Chengbo Lian
Summary: This study focuses on the Longmaxi Formation in the Yanjin-Junlian area of the southern Sichuan Basin, investigating its structural development characteristics and stages. A comprehensive analysis of the formation was conducted, considering surface and underground structural analysis, fluid inclusion tests, apatite fission track experiments, and burial-thermal evolution history analysis. The findings provide guidance for evaluating shale gas preservation conditions and accumulation in the study area.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Engineering, Environmental
C. S. Wang, J. F. Liu, Y. W. Zhao, S. J. Han
Summary: This study investigated the tensile properties and crack modes of Beishan granite using different testing methods. It was found that the failure during the Brazilian splitting test was more severe and cracks expanded more rapidly compared to the direct tensile test. Additionally, a damage constitutive model for the rock was established and the change process of the damage variable was divided into three stages.
BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT
(2022)
Article
Geochemistry & Geophysics
Cunhui Fan, Hubin Xie, Hu Li, Shengxian Zhao, Xiangchao Shi, Jianfeng Liu, Lifeng Meng, Jun Hu, Chengbo Lian
Summary: The southern margin of the Sichuan Basin is characterized by strong structural deformation, complex fault structure styles and scales, and multistaged geological evolution stages, which together have created various shale gas preservation conditions.
Article
Engineering, Mechanical
Chengxing Zhao, Jianfeng Liu, Cheng Lyu, Deng Xu, Chao Liang, Zhicheng Li
Summary: Limestone rock plays a significant role in various rock engineering projects. This study investigated the mechanical behavior, permeability, and failure modes of limestone rock under stress-seepage coupling conditions. The experimental findings indicate that the failure of limestone rock still conforms to the Mohr-Coulomb criterion under stress-seepage coupling. The effective confining pressure can indicate the impact of gas pressure and confining pressure on the deformation parameters of limestone samples. Moreover, the permeability evolution of limestone under different gas pressures and confining pressures exhibits similar trends, with the initial, peak, and residual permeability decreasing with the effective confining pressure.
ENGINEERING FAILURE ANALYSIS
(2022)
Article
Engineering, Geological
Haiyang Zhang, Liang Chen, Jianfeng Liu, Ying Li, Ju Wang
Summary: This study conducted cyclic loading-unloading three-point bending tests on granitic rocks. The results show that the fracture toughness of the rocks decreases by about 10% after saturation. Additionally, the fracture toughness increases with the decrease of mineral grain size. Acoustic emissions reveal the progressive damage characteristics of the granitic rocks.
ROCK MECHANICS AND ROCK ENGINEERING
(2022)
Article
Energy & Fuels
Shuo Zhai, Heping Xie, Peng Cui, Daqin Guan, Jian Wang, Siyuan Zhao, Bin Chen, Yufei Song, Zongping Shao, Meng Ni
Summary: The authors introduce a machine learning-driven approach to accelerate the discovery of efficient oxygen reduction electrodes for ceramic fuel cells by utilizing ionic Lewis acid strength as an effective physical descriptor. Experimental validation confirms the superior activity metrics of four oxides out of 6,871 distinct perovskite compositions, highlighting the importance of ISA in improving oxygen reduction reaction activity in perovskite oxides.
Article
Multidisciplinary Sciences
Heping Xie, Zhiyu Zhao, Tao Liu, Yifan Wu, Cheng Lan, Wenchuan Jiang, Liangyu Zhu, Yunpeng Wang, Dongsheng Yang, Zongping Shao
Summary: This article introduces a method for direct seawater electrolysis for hydrogen production, which can solve the problems of side reactions and corrosion. In the experiment, this method stably operated for over 3200 hours under practical application conditions. The method is efficient, size-flexible, scalable, and has high practical value without increasing the operation cost.
Article
Thermodynamics
Chao Liang, Jian-Feng Liu, Zhao-Wei Chen, Gong-Da Lu, Cheng Lyu, Yi Ren
Summary: This study conducted triaxial creep experiments on salt rock at elevated temperatures and found that the steady creep rate increases with an increase in deviatoric stress and temperature, being more sensitive to temperature changes. High temperatures can weaken the bearing capacity of salt rock, and the volumetric strain also grows with increasing temperature.
JOURNAL OF POROUS MEDIA
(2022)
