Article
Engineering, Geological
Mahmoud Alneasan, Mahmoud Behnia, Abdel Kareem Alzo'ubi
Summary: This study investigated tensile fracturing in different rock types under static and quasi-static strain rates, finding that increasing strain rate leads to higher crack propagation speed while decreasing strain rate helps improve parameters associated with hydraulic fracturing. Width and tortuosity are also affected by strain rate.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2022)
Article
Multidisciplinary Sciences
Kesheng Li, Zhen Zhao, Depeng Ma, Chuanxiao Liu, Jinpeng Zhang
Summary: This study investigates the influence of single fracture dip on the mechanical properties and acoustic emission parameters of rock-like materials through experiments and numerical simulations. The results indicate that as the crack dip angle increases, the rock material's peak strength will be affected, with the lowest strength at a dip angle of 45 degrees. The specimens with prefabricated 45 degrees inclined fractures show the highest degree of deterioration, releasing approximately 1/10 of the energy of other rock-like materials.
ARABIAN JOURNAL FOR SCIENCE AND ENGINEERING
(2022)
Article
Engineering, Mechanical
Haijun Yu, Chunhong Xiao, Jinshan Sun, Yuntao Wang, Meng Wang
Summary: This paper presents a method of determining dynamic fracture parameters of rocks using a blasting experimental measuring system and analyzes the mechanical behavior and fracture mechanism of rocks under blasting through numerical models. The results show that there is a certain relationship between dynamic tensile strength, fracture energy, crack initiation time, and propagation velocity.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2023)
Article
Engineering, Geological
Mingyang Song, Qianting Hu, Huihui Liu, Quangui Li, Yuebing Zhang, Zhifang Hu, Jichuan Liu, Yize Deng, Xuewen Zheng, Mingjie Wang
Summary: Understanding the response mechanism of multiparameter rock fractures is essential for accurate crack diagnosis. This study used three-point bending tests, scanning electron microscopy, and real-time resistivity and acoustic emission data to investigate crack propagation and its correlation with rock resistivity or acoustic emission. The results reveal the influence of crack geometry complexity on circuit connectivity and the relationship between resistivity variation and fracture toughness.
ROCK MECHANICS AND ROCK ENGINEERING
(2023)
Article
Geochemistry & Geophysics
Jianchao Wang, Yan Zhang, Changan Qin, Yaohui Gao, Zhaofeng Wang, Guofeng Zhang
Summary: This paper conducts direct shear tests on jointed rocks with different rock bridge lengths to study their mechanical properties, AE characteristics, and fracture mechanism during failure. Results show that the rock bridge length has a significant influence on shear strength, AE, and fracture mechanism.
Article
Geochemistry & Geophysics
Jianchao Wang, Yan Zhang, Changan Qin, Yaohui Gao, Zhaofeng Wang, Guofeng Zhang
Summary: This paper investigates the mechanical properties, acoustic emission characteristics, and fracture mechanism of jointed rocks with different rock bridge lengths through direct shear tests. The study reveals that the length of the rock bridge plays a significant role in the shear strength, acoustic emission characteristics, and fracture mechanism. The fracture criterion and crack growth angle are derived based on linear elastic fracture mechanics, which are consistent with the experimental results.
Article
Construction & Building Technology
Yan Chen, Jiangfan Yang, Meiheng Li, Lei Zhou, Baohua Guo, Jianping Zuo
Summary: In this paper, laboratory direct shear tests and acoustic emission tests are conducted to analyze the shear properties of bonded rock-concrete interfaces. The results show that increasing roughness enhances brittleness and peak dilatancy characteristics, but the residual shear strength exhibits the opposite trend. The AE tests demonstrate the occurrence of peak AE energy and count generation during shear failure, and the evolution of the AE-b value indicates the repeated conversion between large and small-scale micro-cracks.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Engineering, Geological
Chenxi Ding, Renshu Yang, Liyun Yang
Summary: In this study, static stress is utilized to simulate high in-situ stress in a deep rock mass, and its effect on blast-induced cracking is analyzed. The results show that static stress increases the fractal dimension of the blast-induced crack and the degree of damage to the medium, influencing the propagation behavior of the crack.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2021)
Article
Multidisciplinary Sciences
Hewan Li, Jian Liu, Laigui Wang, Tianjiao Ren
Summary: This paper proposes a method to analyze rock samples with different inclination angles from the standpoint of energy, using the bond-base peridynamic theory and the PMB model of brittle materials, combined with laboratory experiments. The whole process of shearing is analyzed, and the LAMMPS software is used to simulate the internal energy change of rock-like materials under shear conditions. The result shows that prefabricated cracks and the inclination of cracks are important factors for specimen damage, which has important theoretical value for rock mechanics research. The research results can reduce the occurrence of rock burst accidents, the difficulty of mine support, and the cost of mining engineering, as well as improve mine safety levels.
SCIENTIFIC REPORTS
(2023)
Article
Mechanics
Xiaoran Wang, Enyuan Wang, Xiaofei Liu, Xin Zhou
Summary: The study investigated the mechanical and temporal-spatial microcracking behaviors of fractured sandstones under different loading rates using acoustic emission monitoring. The results showed significant static loading rate effects on the mechanical, acoustic, and microcracking processes. Increasing loading rates led to a change in dominant failure modes of fractured sandstones.
ENGINEERING FRACTURE MECHANICS
(2021)
Article
Geochemistry & Geophysics
Yawei Li, Ahmad Ghassemi
Summary: Confined Brazilian tests were conducted to investigate the impact of confining pressure on tensile strength, failure mechanisms, and brittle-ductile transition. Four rock types, including limestone and three sandstones, were tested. Results suggest that the complete strength envelope resembles an offset parabola, with an increase in tensile strength under confinement and a transition from extension to shear as the confining pressure increases.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geochemistry & Geophysics
Jie-Fang Song, Cai-Ping Lu, Xiu-Feng Zhang, Ying Guo, Hong-Wei Yang
Summary: This work combines numerical models and field observations to study the attenuation of stress waves and crack evolution mechanism in jointed rock masses caused by deep-hole blasting. The study finds that larger joint angles result in larger transmission coefficients and smaller fractal dimensions. Additionally, there is a significant time difference between the peak stress difference and maximum principal stress in the horizontal direction of jointed rock masses, while there is no notable difference in the vertical direction. Furthermore, simulations of an unjointed rock mass and multiple parallel joints reveal that larger joint angles lead to smaller particle peak velocities and amplitude attenuations. As the number of stress waves passing through the joints increases, the amplitudes gradually decrease, with high-frequency amplitudes decreasing more significantly than low-frequency amplitudes.
Article
Engineering, Geological
Lizhou Wu, Jianting Zhou, Lin Luo, L. P. Yang
Summary: The relationship between velocity, acceleration, and dynamic fracture toughness during rapid crack propagation is investigated using a novel experiment setup. The dynamic stress intensity factor is studied using an experimental-numerical-analytical method, revealing its variation over time. Furthermore, acceleration is used to analyze the unsteady crack propagation process.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2022)
Article
Agricultural Engineering
Jie Cui, Lin Mi, Lang Li, Yongjie Liu, Chong Wang, Chao He, Hong Zhang, Yao Chen, Qingyuan Wang
Summary: The tensile behavior of Moso bamboo before and after heat treatment was studied in this paper, including tensile strength, stress-strain curve, and crack propagation process. Microstructure and chemical composition analysis were conducted to reveal the underlying mechanism. The tensile strength decreases with increasing treating temperature, and the decomposition of cellulose and hemicellulose is responsible for the decrease. The unique composite structure of bamboo results in a stepwise failure behavior under uniaxial tensile load, with fiber sheaths breaking dispersively and causing the strain-stress curve to fluctuate like stairs.
INDUSTRIAL CROPS AND PRODUCTS
(2023)
Article
Engineering, Mechanical
Mingyang Teng, Jing Bi, Yu Zhao, Chaolin Wang
Summary: This study proposes a method for making rock-like samples containing embedded 3D flaws, and conducts a series of shear tests under different normal stresses. The test results show that the complex shear stress-shear displacement curve can be divided into four stages. The shear strength, residual strength, and shear modulus of the specimens are affected by the flaw dip angle and normal stress. Tensile failure is more likely to occur in low stress and small flaw angle specimens, while shear failure mainly occurs in high stress specimens. A sudden increase in AE counts, AE event rates, and a sudden decrease in b-value are usually precursors to rock failure. The RA/AF value can accurately reflect the classification and development of rock tension shear cracks. Damage locations of rock-like specimens in each stage are effectively identified through Kernel density estimation (KDE) analysis on the distribution of AE events. The movement of the maximum density point is consistent with the tendency of rock crack propagation, almost following the uniform diffusion of the specimens from the middle to the end.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2023)
Article
Engineering, Geological
Hongbo Du, Feng Dai, Mingdong Wei, Ang Li, Zelin Yan
Summary: The study finds that static confining pressure and dynamic loading rate enhance the load-carrying capacity of rocks, but the shear component limits the dynamic peak stress. With an increase in static confining pressure, the failure surface expands outward, while the compressive deformation modulus of rocks decreases with increasing shear component. The fragmentation behavior of rocks is restricted by static confining pressure and the shear component of dynamic loading, leading to a change in failure pattern as specimen inclination angle and static confining pressure increase.
ROCK MECHANICS AND ROCK ENGINEERING
(2021)
Article
Engineering, Multidisciplinary
Ruochen Jiang, Feng Dai, Yi Liu, Ang Li
Summary: This study developed a microseismic (MS) location method using the fast marching method (FMM) and a second-order difference approach, which was validated through numerical experiments and successfully applied to locate blasting activities and MS events. The method significantly reduced location errors, providing a more accurate rock fracture location.
Article
Engineering, Geological
Peng Feng, Yuan Xu, Feng Dai
Summary: In rock specimens containing fissures, the type of cracks, strain rate, and symmetry of the fissures all have an impact on dynamic strength and energy dissipation under dynamic conditions. The dynamic strength of rock specimens significantly increases with increasing strain rate, while the dynamic elastic modulus remains constant regardless of loading rate. Additionally, the distribution of fragment size and energy dissipation density are also affected by the characteristics of the fissures.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2021)
Article
Mechanics
Zelin Yan, Feng Dai, Yi Liu, Ang Li, Hongbo Du
Summary: This study numerically investigates the rate-dependent progressive cracking behaviors of single-flawed rock specimens under different strain rates. The results show that the progressive cracking behaviors of rock specimens exhibit evident changes with increasing strain rates.
ENGINEERING FRACTURE MECHANICS
(2021)
Article
Engineering, Multidisciplinary
Ruochen Jiang, Feng Dai, Yi Liu, Ang Li
Summary: A new discriminant method is developed to automatically recognize Microseismic (MS) and blasting signals based on their time-frequency spectrum characteristics, providing more reliable data for MS monitoring analysis and reducing the impact of operators' subjectivity.
Article
Geosciences, Multidisciplinary
Weigang Shen, Tao Zhao, Feng Dai
Summary: This study investigates the influence of particle size on the buffering efficiency of a soil cushion layer through experimental and numerical tests. It is found that particle size can significantly affect the impact force, especially in high-velocity impacts. These findings offer insights for designing effective soil cushion layers for protection structures.
Article
Instruments & Instrumentation
Youzhen Li, Feng Dai, Wei You, Yi Liu
Summary: Understanding the fracture behavior of brittle rocks under dynamic mixed mode I/II loading is important for rock engineering structures. This study introduces a novel experimental method to investigate this fracture behavior, showing significant loading rate dependence of dynamic fracture toughness. The results demonstrate the feasibility and reliability of the method, revealing deviations in fracture path under mixed mode loading compared to pure mode loading.
REVIEW OF SCIENTIFIC INSTRUMENTS
(2021)
Article
Engineering, Geological
Quanbo Luo, Feng Dai, Yi Liu, Mengtan Gao, Zongchao Li, Ruochen Jiang
Summary: This study focuses on the potential impact of large velocity pulses during earthquakes on buildings, extracting pulse parameters from the 1999 and 2018 earthquakes and evaluating their seismic response on structures. The results show that velocity pulses can cause severe damage to structures, and exceeding seismic design values in long-period spectral values can exacerbate the vulnerability of high-rise buildings to earthquakes.
ROCK MECHANICS AND ROCK ENGINEERING
(2021)
Article
Energy & Fuels
Xinying Liu, Feng Dai, Yi Liu, Pengda Pei, Zelin Yan
Summary: Research indicates that the dynamic tensile strength of naturally saturated specimens increases with loading rate, but decreases with pre-tension. Additionally, the dynamic strength of naturally saturated sandstone is lower than that of natural sandstone, with similar fracture behavior. Water effects on mechanical properties, water wedging effect, and Stefan effect explain the dynamic tensile behavior of rocks with static preload.
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)