Article
Thermodynamics
Xuanhong Du, Junhua Xue, Yu Shi, Chen-Rui Cao, Chi -Min Shu, Kehan Li, Qian Ma, Keliang Zhan, Zhiheng Chen, Shulou Wang
Summary: This paper conducted triaxial loading tests on coal samples from a deep coal mine in China to investigate damage, failure, and transformation of coal. The results showed that the specimens exhibited obvious brittle failure characteristics under single-axis loading, and ductile failure characteristics increased with confining pressure. The ultimate strength and residual strength of the samples had a linear relationship with confining pressure. The study also revealed the different stages of the coal body damage process based on the change trend of damage variable. The analysis of energy conversion characteristics indicated that confining pressure could inhibit fracture expansion and enhance energy storage capacity. Additionally, the study found that greater confining pressure led to higher ultimate elastic energy of the samples. This research is highly significant for understanding high energy level disasters in deep mines.
Article
Engineering, Geological
Xing Li, Wei Yao, Chonglang Wang
Summary: Dynamic fragmentation is a primary fracture type for rock mass in rock engineering, and it is crucial for fragmentation optimization. Multiple dynamic loading leads to the production of more fragments and influences the size distribution, especially when the loading rate is lower. Multiple loading pulses decrease the mean fragment size and generate more fine grains compared to single loading pulses. Therefore, single dynamic compressive loading should be used when evaluating the dynamic fragmentation efficiency of rocks to avoid inaccurate fragmentation size analysis.
ROCK MECHANICS AND ROCK ENGINEERING
(2021)
Article
Chemistry, Multidisciplinary
Junce Xu, Hai Pu, Ziheng Sha
Summary: This study investigated the effects of saturation and impact loading on the dynamic mechanical behavior of frozen red sandstone. The results showed that increased saturation reshaped the pore structure of the frozen sandstone and promoted the expansion of pores. Under impact loading, the dynamic strength, elastic modulus, and brittleness index increased and then decreased with saturation.
APPLIED SCIENCES-BASEL
(2022)
Article
Chemistry, Physical
Zhan-Yang Chen, Jun Yang
Summary: The study found that the static tensile strength of CFRC increases significantly with the increase of fiber content, but the growth rate tends to decrease. The dynamic tensile strength and dynamic increase factor (DIF) both increase with the increase of stress rate, but the growth rate slows down, showing an obvious rate effect. The rate sensitivity of ordinary concrete is higher than CFRC. Significant differences exist in the influence of carbon fiber on the dynamic and static strength of concrete. In the design of concrete mixing proportion, the content of carbon fiber should be appropriately selected to meet the requirements of dynamic and static mechanical properties.
Article
Engineering, Geological
Tubing Yin, Bingqiang Wu, Chao Wang, You Wu
Summary: Research on the dynamic tensile behavior of microwave-irradiated rock is significant for microwave-assisted tunneling and mining. Microwave heating and rapid cooling were found to decrease the P-wave velocity and dynamic tensile strength of basalt specimens. High power and short time radiation caused more damage. Scanning electron microscopic images confirmed the micro-damage caused by microwaves to the basalt specimens.
ROCK MECHANICS AND ROCK ENGINEERING
(2022)
Article
Engineering, Geological
D. R. Manohar, P. Anbazhagan
Summary: The shear strength characteristics of geosynthetic-reinforced rubber-sand mixture (RSM) were investigated by analyzing the size effect of rubber, different rubber content proportions, types and layers of geosynthetics, and their arrangement. The reinforced RSM showed enhanced strength and energy absorption capacity, as well as decreased brittleness index values.
GEOTEXTILES AND GEOMEMBRANES
(2021)
Article
Chemistry, Multidisciplinary
Diyuan Li, Minggang Han, Quanqi Zhu
Summary: Rock is a brittle material, and evaluating its brittleness index is important for various applications. The current methods measure brittleness under static load, and whether it is applicable under dynamic load needs to be explored.
APPLIED SCIENCES-BASEL
(2023)
Article
Engineering, Mechanical
Ri-hong Cao, Hongzhe Wang, Xianyang Qiu, Changsong Wang, Hang Lin, Qiuqiu Qiao
Summary: Rock specimens subjected to cyclic impact experienced mesoscale fracture and strength deterioration. The number of impacts led to decreased dynamic peak stress and increased maximum strain and energy absorption. Cyclic impacts also caused continuous damage and more obvious white spots in the specimens with higher impact times. The fracture toughness decreased with increasing impact number, and the fractal characteristics of the fracture surface became more pronounced.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2023)
Article
Engineering, Mechanical
Yue Zhai, Fandong Meng, Yubai Li, Yan Li, Ruifeng Zhao, Yunsheng Zhang
Summary: This study focuses on the micro-damage, macro-fracture characteristics, and dynamic properties of Tongchuan sandstone in northwest China after freeze-thaw. The results show that the impact loading has a greater effect on the rocks compared to freeze-thaw, and this effect weakens as the rocks soften. A new damage constitutive model considering various forms of dissipated energy has been proposed.
ENGINEERING FAILURE ANALYSIS
(2022)
Article
Nanoscience & Nanotechnology
Kang Du, Yang Zhang, Zhongwu Zhang, Tao Huang, Guangda Zhao, Liyuan Liu, Xiyu Wang, Lixin Sun
Summary: This paper systematically investigated the effects of V on the formation of precipitates and mechanical properties in Fe-Ni-Co-Al-Nb alloy. It was found that the addition of V can improve the strength by forming nano-sized gamma' precipitates, and significantly improve the elongation of the alloy.
MATERIALS SCIENCE AND ENGINEERING A-STRUCTURAL MATERIALS PROPERTIES MICROSTRUCTURE AND PROCESSING
(2022)
Article
Mechanics
Xiaogang Wu, Shuren Wang, Jianhui Yang, Jianqing Zhao, Xu Chang
Summary: The study found that damage in lightweight shale ceramsite concrete under static-dynamic loads is mainly caused by collapse of the structure in the aggregate, with circumferential prestressing having an inhibitory effect on the damage factor. The dynamic Drucker-Prager strength criterion for LWSCC was established and a new damage constitutive model, with clear physical meaning to parameters, was proposed for describing the mechanical response of LWSCC under static-dynamic loads.
ENGINEERING FRACTURE MECHANICS
(2022)
Article
Construction & Building Technology
Zhenyu Huang, Weining Pan, Shilin Du, Yingwu Zhou, Jianqiao Ye
Summary: The incorporation of fiber and rubber into concrete can enhance its tensile strength and impact resistance. In this study, a new rubberized ultra-lightweight high ductility cement composite (RULHDCC) was developed by mixing waste rubber particles and polyethylene (PE) fiber into an ultra-lightweight cement composite (ULCC). The study conducted Split Hopkinson Pressure Bar (SHPB) splitting tests and showed that the splitting behavior of RULHDCC was significantly improved due to the synergistic effect of rubber and fiber, without much loss of compressive strength. The tension-Dynamic Increasing Factor (DIF) models were evaluated and the limitations of the research were highlighted.
CONSTRUCTION AND BUILDING MATERIALS
(2023)
Article
Engineering, Marine
Yushun Lian, Bin Zhang, Jinhai Zheng, Haixiao Liu, Gang Ma, Solomon C. Yim, Yanbin Zhao
Summary: This study proposes an experimental method and procedure to investigate the residual strength of damaged ropes. The test results show that the residual strength of damaged ropes decreases with increasing damage level. An empirical equation for predicting the residual strength of damaged ropes is proposed, and an upper and lower bound method is proposed to evaluate the residual strength of polyester mooring ropes.
Article
Engineering, Mechanical
Gongwei Zhao, Yating Liu, Nanhai Ye
Summary: This paper presents an improved accumulation damage model based on the Manson-Halford (M-H) model, which is closer to the actual conditions. The model considers both the effect of load interaction and the phenomenon of strength degradation of materials induced by loading history. In addition, a new logarithmic residual strength model is proposed and its accuracy is verified. The experimental data shows that the improved model has better applicability and higher accuracy.
INTERNATIONAL JOURNAL OF FATIGUE
(2022)
Article
Engineering, Geological
Wenkai Ru, Shanchao Hu, Aohui Zhou, Pingkuang Luo, Hao Gong, Chenxi Zhang, Xuedong Zhou
Summary: Weakly cemented soft rock (WCSR) strata are widespread in Western China and their creep characteristics significantly affect coal mine safety production. Creep tests were performed under different initial confining pressures and a nonlinear damage constitutive model was constructed to describe the creep failure process. The results showed that the initial confining pressure influenced the stability and creep rate of WCSR. Criteria for determining creep deformation stability of WCSR roadways and support suggestions were proposed based on this study.
ROCK MECHANICS AND ROCK ENGINEERING
(2023)
Article
Engineering, Mechanical
Diyuan Li, Chenxi Zhang, Quanqi Zhu, Jinyin Ma, Feihong Gao
Summary: The deformation behavior, damage and fracture characteristics of granite specimens were tested and observed using 3D-DIC and SCC method. The study found that damage in the region of interest increases with axial stress, relative displacements indicate tensile-shear mixed mode fracture in SCC specimens, and new fracture initiates from the middle part of ESFB. Fracture energy of granite is estimated as 1760.4 J/m² based on energy conservation law.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2022)
Article
Engineering, Mechanical
Jinyin Ma, Diyuan Li, Quanqi Zhu, Meng Liu, Qianrong Wan
Summary: Through a series of experiments, it was found that the Mode I fatigue fracture behavior of hard rock is significantly affected by dynamic disturbance, with the nonlinearity degree p increasing with increasing pre-static load levels, and the disturbance frequency having a significant impact on corrected fracture toughness.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2022)
Article
Geochemistry & Geophysics
Peng Xiao, Diyuan Li, Quanqi Zhu
Summary: In this study, a method to calculate the release of strain energy caused by excavation in pre-stressed rock is proposed. The influence of excavation height and width on strain energy release is inconsistent. The increase in lateral pressure coefficient leads to an exponential increase in strain energy release.
Article
Engineering, Geological
Quanqi Zhu, Chongjin Li, Xibing Li, Diyuan Li, Weihua Wang, Jiangzhan Chen
Summary: Understanding the stress distribution, deformation and fracture behavior around a circular hole or inclusion is critical for the stability assessment of rock structures. The results show that filling the hole or inclusion can increase the stress and displacement of the inclusion while decreasing the stress and displacement around the surrounding rock, thereby improving the strength and deformation properties. In addition, the crack types and initiation positions around the filled and unfilled holes are quite different.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2022)
Article
Chemistry, Analytical
Chunde Ma, Zihe Wang, Jiaqing Xu, Guanshuang Tan, Zhihai Lv, Quanqi Zhu
Summary: This study developed a measurement system for studying the gas generation of coal-rock under temperature-pressure coupling, which can provide accurate and effective measurement means for the study of gas production by coal-rock deformation.
Article
Engineering, Mechanical
Zhenyu Han, Shijie Xie, Diyuan Li, Quanqi Zhu, Zhiwei Yan
Summary: In this study, dynamic uniaxial compressive tests were conducted to investigate the effects of inclusion conditions on the dynamic mechanical properties and failure mechanism of sandstone specimens. The study found that the inclusions effectively enhanced the dynamic strength of flawed specimens, but had a slight effect on the final failure pattern.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2022)
Article
Mechanics
Chenxi Zhang, Diyuan Li, Jinyin Ma, Quanqi Zhu, Pingkuang Luo, Yuda Chen, Minggang Han
Summary: The influence of loading rate on the mode I fracture property of rocks has been extensively studied, but the rate-effect of dynamic mode II fracture is rarely reported. This study conducted a series of dynamic mode II fracture tests under a wide range of loading rates using the modified split Hopkinson pressure bar (SHPB) system. The results showed that the dynamic mode II fracture toughness increases with loading rate, and the fracture processes can be divided into multiple stages.
ENGINEERING FRACTURE MECHANICS
(2023)
Article
Engineering, Mechanical
Xiaoli Su, Diyuan Li, Quanqi Zhu, Jinyin Ma
Summary: This study investigated the effects of fatigue loads on hydraulic fracturing in granite under different stress states. The results showed that the amplitudes of cyclic load had a significant impact on fracture initiation pressure and fracture morphology. Higher amplitude disturbance in the intermediate principal stress direction resulted in lower breakdown pressure and wider fractures. Increasing disturbance frequency led to the generation of complex fatigue cracks, which could weaken the rock strength.
FATIGUE & FRACTURE OF ENGINEERING MATERIALS & STRUCTURES
(2023)
Article
Engineering, Mechanical
Quanqi Zhu, Diyuan Li, Xibing Li, Zhenyu Han, Jinyin Ma
Summary: The cracked straight through Brazilian disc (CSTBD) specimen was used to investigate the I/II mixed mode static fracture of diorite in this study. The results showed that the fracture mechanical behavior and trajectories were influenced by the crack angle. Fracture energy and crack mouth opening displacement (CMOD) were characterized, and a fracture energy calculation method considering primary crack growth was proposed. The proposed EEMTSN criterion had the best prediction effect on the mixed mode fracture toughness of diorite.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2023)
Article
Engineering, Geological
Diyuan Li, Zida Liu, Quanqi Zhu, Chenxi Zhang, Peng Xiao, Jinyin Ma
Summary: This paper presents a quantitative method based on SEM images and deep learning to identify the mesoscopic failure mechanism of granite, which can determine the distribution of tensile and shear fractures on failure surfaces. The developed AlexNet models achieved high accuracy (96-98%) in identifying tensile and shear fracture surfaces. The results verified the application of the proposed method and its usefulness in understanding the failure mechanism of rock under uniaxial compression.
ROCK MECHANICS AND ROCK ENGINEERING
(2023)
Article
Environmental Sciences
Xibing Li, Yanan Zhou, Ying Shi, Quanqi Zhu
Summary: Waste recycling methods could cause secondary pollution, and therefore considerations for such pollution are necessary. Cemented phosphogypsum (PG) backfill has been proven as a cost-effective method for recycling PG, but stabilizing impurity fluoride has been challenging due to environmental conditions. This study examined the immobilization and release of fluoride in PG backfill and its impact on strength. Results showed that fluoride could be temporarily immobilized by PG, but when binder was added to the mix, the increased pH caused the re-release of immobilized fluoride into the backfill slurry. Furthermore, fluoride hindered binder hydration and weakened backfill structure, thereby affecting its strength.
SCIENCE OF THE TOTAL ENVIRONMENT
(2023)
Article
Engineering, Mechanical
Quanqi Zhu, Diyuan Li, Jinyin Ma, Zhenyu Han, Xibing Li
Summary: The dynamic mixed mode I/II fracture properties of hard rock were investigated through split-Hopkinson pressure bar tests on cracked straight through Brazilian disc (CSTBD) diorite specimens. The fracture load and toughness for different crack angles or mode mixities were determined. The dynamic fracture process and crack mouth opening displacement (CMOD) were monitored, and the fractal and morphology characteristics of fracture surfaces were analyzed. The study found that the CMOD behavior is closely related to the force acting on the crack surface, and the allowable CMOD decreases with increasing crack angle. Stress-based and strain-based fracture criteria were introduced, and the GMTS criterion and EMTSN criterion showed the best prediction effect for fracture toughness and crack initiation angle respectively. Observation results showed that the macro fracture trajectories were controlled by the prefabricated crack angle, while the mode mixity had little impact on the meso-roughness and micro-morphology of the fracture surface. The fracture surface of CSTBD diorite specimen exhibited mixed tensile-shear cracks under dynamic load.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2023)
Article
Chemistry, Multidisciplinary
Diyuan Li, Minggang Han, Quanqi Zhu
Summary: Rock is a brittle material, and evaluating its brittleness index is important for various applications. The current methods measure brittleness under static load, and whether it is applicable under dynamic load needs to be explored.
APPLIED SCIENCES-BASEL
(2023)
Article
Chemistry, Physical
Yanan Zhou, Ying Shi, Quanqi Zhu
Summary: This study investigated the effects of citric acid pretreatment on defluorination, backfill performance, and environmental behavior of phosphogypsum (PG). The results showed that citric acid pretreatment significantly reduced the fluoride content in PG and promoted the hydration reaction with the binder, thus reducing the usage and cost of the binder. The optimal citric acid concentration and washing times were determined to be 4% and 7-8 times, respectively. In addition, citric acid pretreatment improved the flowability and strength of the backfill slurry, and reduced the fluoride content in the bleeding water and backfill leachate, meeting the wastewater discharge standard. These findings provide important guidance for the large-scale recycling and environmental management of PG.
