Article
Engineering, Mechanical
Qi Zhang, Feng Dai, Yi Liu
Summary: Rock engineering structures are vulnerable to cyclic coupled compression-shear loading, and accurately characterizing the dynamic behaviors of rocks is crucial for construction safety and disaster prevention. A testing method is proposed in this study to characterize the fatigue response of rocks under cyclic compression-shear loading by using inclined specimens under cyclic uniaxial loading. The experimental results show the effects of tilting angle and loading frequency on the dynamic properties of rocks, and a fatigue life prediction function is proposed based on these results.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2022)
Article
Engineering, Mechanical
Peng Li, Meifeng Cai, Yubing Gao, Peitao Wang, Shengjun Miao, Yu Wang
Summary: The presence of cross joints and the change in included angles significantly affect the strength and deformation properties of brittle jointed rocks. Observations in mechanics, acoustics, and optics provide a comprehensive understanding of the fracture evolution and failure behavior around openings.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2022)
Article
Construction & Building Technology
Qian Xia, Tingliang Yi, Yiqing Li, Chunke Shen, Daguan Huang, Yuanqing Sun
Summary: Urban expansion and diversified traffic have worsened the damage of ancient buildings. Evaluating the long-term fatigue performance of ancient brick masonry structures is crucial for their safety and maintenance. Indoor tests using VIC-3D technology were conducted, establishing the relationship between stress level and failure cycles, as well as the stress-strain evolution under different stress levels. A mathematical model based on probability was proposed for fatigue life prediction, considering maximum stress level, stress range, load cycles, and survival probability. The test results provide reliable support for fatigue deterioration and life prediction of ancient masonry structures.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Review
Engineering, Geological
Yi Liu, Feng Dai
Summary: This study comprehensively reviews the deformation, failure mechanism, and fatigue constitutive relationship of rocks subjected to cyclic loading over the past 60 years. It classifies cyclic tests on rocks, summarizes fatigue responses, discusses the influences of cyclic loads, outlines constitutive relationships, and suggests future research directions.
JOURNAL OF ROCK MECHANICS AND GEOTECHNICAL ENGINEERING
(2021)
Article
Engineering, Geological
Feng Dai, Qi Zhang, Yi Liu, Hongbo Du, Zelin Yan
Summary: This study investigates the influence of cyclic coupled compression-shear loading on the fatigue mechanical response of inclined sandstone specimens. The testing results reveal the deformation characteristics, energy evolution, damage variable, and failure mechanism under different loading conditions. A fatigue life prediction method based on energy dissipation is proposed and validated against experimental results. The cracking behavior of rocks during fatigue tests is analyzed using digital image correlation technique.
Article
Engineering, Geological
Kui Zhao, Lin Zhang, Daoxue Yang, Jiefang Jin, Peng Zeng, Xing Wang, Shanhu Ran, Dongming Deng
Summary: This study investigates the mechanical behavior and Kaiser effect of rock samples under cyclic impact loading damage and water saturation through a series of tests. The results show that the cyclic loading and unloading strength of rock samples in saturated condition decreases compared to those not subjected to cyclic impact loading. The water-rock interaction plays a crucial role in this phenomenon. The study suggests that drilling of cores from stress-disturbed areas should be avoided during in situ stress measurement.
ROCK MECHANICS AND ROCK ENGINEERING
(2023)
Article
Engineering, Mechanical
Peng Li, Meifeng Cai, Yubing Gao, Mostafa Gorjian, Shengjun Miao, Yu Wang
Summary: Uniaxial compression tests were conducted on jointed granite samples with openings to investigate the macro/mesofracture and instability behaviors. The results showed that the peak strength and elastic modulus of the samples first decreased and then increased with increasing joint angle, reaching a minimum at around 45 degrees. The AE cumulative count before the peak stress was related to crack initiation or interpenetration, while the instantaneous increase in the AE count after the peak stress was associated with the stress drop caused by high strain localization or the formation of visible cracks. The accelerated release of AE energy can provide early warning for rock instability and failure. The existence of joints changed the stress distribution patterns and interacted with high stress concentration areas to dominate the fracturing process.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2022)
Article
Materials Science, Multidisciplinary
Peng Li, Mei-feng Cai, Pei-tao Wang, Qi-feng Guo, Sheng-jun Miao, Fen-hua Ren
Summary: The inclination angle has a significant impact on the mechanical response and energy evolution of granite specimens, with the strength and deformation parameters reaching minimum values at an inclination angle of 45 degrees. The peak total energy, peak elastic strain energy, and peak dissipated energy show nonlinear characteristics with increasing inclination angle.
INTERNATIONAL JOURNAL OF MINERALS METALLURGY AND MATERIALS
(2021)
Article
Engineering, Civil
Bin Fu, Chun'an Tang
Summary: Through conducting three different cyclic loadings on marble, it was found that the continuous decreasing correlation dimension and b value can be considered a robust signal of imminent rock failure. Additionally, extra cyclic loadings increase low-energy AE events and cause a change in AE distribution.
GEOMECHANICS AND ENGINEERING
(2021)
Article
Geosciences, Multidisciplinary
Zhixi Liu, Xiaodie Liu
Summary: This study aims to investigate the evolution of residual strain and strain energy in rocks under uniaxial cyclic loading-unloading experiments. Four types of rocks, coal, white sandstone, red sandstone, and granite, were subjected to different uniaxial cyclic loading-unloading experiments. The findings reveal that residual strain gradually decreases and eventually disappears with an increasing number of cycles. However, if the cyclic loading-unloading is continued beyond this point, the rocks display a reappearance of residual strain. The number of cycles required to eliminate residual strain is inversely proportional to the peak strength of the rocks and directly proportional to the upper limit value of uniaxial cyclic loading-unloading experiments. The study of mechanical properties and strain energy evolution under cyclic loading-unloading is of positive significance for the development of rock fatigue damage and rock damage mechanics.
FRONTIERS IN EARTH SCIENCE
(2023)
Article
Materials Science, Characterization & Testing
Zhicheng Gong, Wendong Yang, Ling Wang, Lindong Fang, Weiteng Li, Yiwei Li
Summary: Bolt reinforcement can significantly improve the strength and modulus of jointed rock mass. The strength of the bolted rock-like specimen increases with the joint angle and decreases with the anchorage angle. The bolted specimens exhibit better ductility and integrity.
JOURNAL OF TESTING AND EVALUATION
(2023)
Article
Engineering, Geological
Tao Zhang, Weiya Xu, Huanling Wang, RuBin Wang, Long Yan, MingTao Hu
Summary: The study investigated the anisotropic mechanical behavior of columnar jointed rock masses (CJRM) under different joint dip angles. Results showed that the relationship between stress thresholds and joint dip angles exhibited a typical U-shape, with mechanical parameters gradually increasing with stress, and three main failure modes observed during the loading process.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2021)
Article
Engineering, Geological
Waranga Habaraduwa Peellage, Behzad Fatahi, Haleh Rasekh
Summary: In this study, the dynamic properties of jointed rock specimens were investigated using cyclic triaxial tests. The results showed that the level of confining pressure, cyclic deviatoric stress amplitude, and joint type had a significant influence on the dynamic characteristics of the specimens. Increasing confining pressure and cyclic deviatoric stress amplitude led to higher residual axial strains and damping ratios, while reducing resilient moduli and dissipated energy. Moreover, the relationship between the number of cycles and the residual axial strain, resilient moduli, damping ratio, and dissipated energy was examined.
SOIL DYNAMICS AND EARTHQUAKE ENGINEERING
(2022)
Article
Engineering, Mechanical
Dong Xiang, Yinhua Shen, Xinyu Sun
Summary: A new energy parameter suitable for tension-compression is proposed, which includes an improved strain-energy model and a strain-energy ratio. The improved strain-energy model distinguishes tensile and compressive deformation by judging the volume change of the micro-element. The strain-energy ratio characterizes the alternate tensile and compressive deformation under asymmetric cyclic loading. A modeling approach for fatigue life estimation based on the strain-energy ratio is introduced, and three example models are exhibited. Experimental analysis of a cantilever beam under asymmetric cyclic loading validates the effectiveness of the improved energy parameter and the applicability of the strain-energy ratio-based model in fatigue analysis.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2023)
Article
Engineering, Civil
Wei Wang, Shengyao Mei, Yajun Cao, Rubin Wang, Qizhi Zhu
Summary: Chemical corrosion significantly degrades the mechanical properties of non-persistently jointed rocks. In order to improve their physical and mechanical properties, a modification test was conducted using silicone immersion and resin filling in the pre-existing joints after chemical corrosion. Triaxial compression tests confirmed that the modification greatly enhanced the peak strength, elastic modulus, and deformation modulus of jointed rocks. SEM and EDS analysis revealed the mechanism behind the strength improvement induced by the modification.
EUROPEAN JOURNAL OF ENVIRONMENTAL AND CIVIL ENGINEERING
(2023)
Article
Mechanics
Zelin Yan, Feng Dai, Yi Liu, Mingdong Wei, Wei You
Summary: This study investigates the progressive failure process of flattened Brazilian disc (FBD) specimen using digital image correlation technique and proposes a modified calculation method to determine mode-I fracture toughness KIC. Additionally, the cracking nature of secondary cracks and the second rise of loading force induced by compressionshear failure near the flattened ends of the FBD specimen are identified. These findings contribute to a better understanding of the progressive fracture mechanism of FBD specimens and enhance the accuracy of KIC calibration by FBD testing method.
ENGINEERING FRACTURE MECHANICS
(2021)
Article
Engineering, Geological
Zelin Yan, Feng Dai, Jianbo Zhu, Yuan Xu
Summary: This study systematically investigated the influences of pre-stress ratio, flaw inclination angle, and strain rate on the dynamic progressive cracking mechanism and energy evolution of multi-flawed rocks. The experimental results show that the dynamic/total strength generally increases with increasing strain rate, decreases with increasing flaw inclination angle, and exhibits complex changes with increasing pre-stress ratio.
ROCK MECHANICS AND ROCK ENGINEERING
(2021)
Article
Engineering, Mechanical
Zhiheng Wang, Yong Li, Weibing Cai, Weishen Zhu, Weiqiu Kong, Feng Dai, Chen Wang, Kai Wang
Summary: This study investigated the initiation mechanism of microcracks in fractured rock mass from the perspective of micromechanics, establishing macro-micro criteria to determine and distinguish the properties and types of cracks. It was found that the stress state of rock particles determines the type and propagation direction of cracks, allowing for an effective analysis of the initiation mechanism of different types of cracks and their propagation trends.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2021)
Article
Engineering, Mechanical
Mingdong Wei, Feng Dai
Summary: Laboratory-scale experiments were conducted on mixed-mode I/II fracture of non-oriented columnar saline ice, showing that temperature and loading conditions significantly influence the fracture behavior of ice. The results demonstrated that T-stress plays a crucial role in mixed-mode fracture of ice, with both trans- and inter-granular crack growth observed under different testing conditions.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2021)
Article
Construction & Building Technology
Ang Li, Feng Dai, Yi Liu, Hongbo Du, Ruochen Jiang
Summary: A novel dynamic method is proposed for evaluating the stability of high sidewalls subjected to flexural-toppling by integrating derived criterion, continuum modelling and microseismic data. The study defines a geo-mechanical model for analyzing toppling rock strata on high sidewalls and deduces potential energies equations using the Rayleigh-Ritz method. A quantitative stability evaluation methodology is presented considering progressive failure and the influence of fractures along bedding planes.
TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY
(2021)
Article
Environmental Sciences
Li Qian, Jianhai Zhang, Xianliang Wang, Yonghong Li, Ru Zhang, Nuwen Xu, Zhiguo Li
Summary: In this study, the creep behavior of granite in Shuangjiangkou underground powerhouse was investigated, and a new parameter DPR, the ratio of deviatoric stress to peak strength, was proposed. Based on the test results, an improved generalized Kelvin creep model was introduced to accurately describe the primary and secondary creep behavior of granite under given deviatoric stresses and confining pressures.
ENVIRONMENTAL EARTH SCIENCES
(2022)
Article
Multidisciplinary Sciences
Li Qian, Tianzhi Yao, Zuguo Mo, Jianhai Zhang, Yonghong Li, Ru Zhang, Nuwen Xu, Zhiguo Li
Summary: This study proposed a method using generative adversarial network (GAN) to optimize lateral stress coefficients of ancient stress fields, estimating the approximate ancient stress field by simulating valley evolution, and validating its effectiveness through numerical tests.
SCIENTIFIC REPORTS
(2021)
Article
Geosciences, Multidisciplinary
Quanfu Ding, Biao Li, Haijian Su, Nuwen Xu, Xuehua Li, Xingyang Deng
Summary: High geo-stresses and complicated geological conditions are typical characteristics in the traffic tunnel of the tailrace surge chamber at the Shuangjiangkou hydropower station. Microseismic monitoring technology helped evaluate rock mass stability and reveal rock fracturing mechanisms. Weak structures and the multi-cavern effect exacerbated rock mass damage during excavation-unloading, with tensile failure being the main fracturing type.
GEOMATICS NATURAL HAZARDS & RISK
(2022)
Article
Engineering, Geological
Xiao Huang, Nuwen Xu, Wei Wu, Peiwei Xiao, Linlu Dong, Biao Li
Summary: This study uses microseismic monitoring and numerical modeling to investigate the stability of intersecting discontinuities in rock masses. The results suggest that the stability is influenced by geological features and mechanical properties, emphasizing the importance of paying attention to key properties favorable for rock instability.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2022)
Article
Metallurgy & Metallurgical Engineering
Biao Li, Quan-fu Ding, Nu-wen Xu, Feng Dai, Yuan Xu, Hong-lue Qu
Summary: Rock mass large deformation in underground powerhouse caverns is a significant hazard in hydropower engineering in Southwest China. Microseismic monitoring techniques can be used to detect the fractures generated during the development of rock mass large deformation. The study analyzes the MS b-values associated with rock mass large deformation and their temporal variation, and provides valuable information for understanding the fracturing characteristics of MS sources and early warning of rock mass large deformation in underground powerhouse caverns.
JOURNAL OF CENTRAL SOUTH UNIVERSITY
(2022)
Article
Engineering, Geological
Peiwei Xiao, Haoyu Mao, Bo Qian, Biao Li, Xingguo Yang, Nuwen Xu
Summary: A high-precision microseismic monitoring system was established to monitor surrounding rock micro-fractures in the underground powerhouse of Shuangjiangkou Hydropower Station. Qualitative analysis of the damage mechanism of surrounding rock microfractures was conducted based on the source parameters of microseismic events. Numerical analysis using FLAC3D showed that considering microseismic damage can better reflect the actual situation of the field. The microfractures in the surrounding rock mainly exhibited mixed failure characteristics, with shear failures localized in certain areas and large fractures in the vault section.
JOURNAL OF ROCK MECHANICS AND GEOTECHNICAL ENGINEERING
(2022)
Article
Construction & Building Technology
Zhonghua Hu, Bangbiao Wu, Nuwen Xu, Kai Wang
Summary: This study investigates the failure mechanism of rock masses in the underground powerhouse caverns of the Baihetan hydropower station and finds that discontinuities significantly affect the stability of rock masses. A risk boundary, affected by discontinuities, is proposed to evaluate roof stability. The study provides valuable insights for the design of excavation and support systems in underground engineering projects.
TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY
(2022)
Article
Construction & Building Technology
Jinyong Zhang, Nuwen Xu, Wei Wu, Peiwei Xiao, Biao Li, Linlu Dong
Summary: This study explores the application of the fast marching method (FMM) to improve the accuracy of microseismic source location in faulted rock masses, showing the potential to enhance location accuracy for P-wave propagation and indicating the need for further improvement.
TUNNELLING AND UNDERGROUND SPACE TECHNOLOGY
(2022)
Article
Multidisciplinary Sciences
Li Qian, Jianhai Zhang, Xianliang Wang, Yonghong Li, Ru Zhang, Nuwen Xu, Zhiguo Li
Summary: The time-dependent behaviors of rocks, such as creep, are closely related to the long-term applied stress in underground engineering projects. By introducing a new dimensionless parameter DPR, the creep behavior of granite under different stress conditions can be effectively analyzed. A unified method for defining the long-term strength of rocks based on DPR and the secondary creep strain rate is proposed.
ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING
(2021)