Article
Engineering, Geological
Xiao Ma, Wenbao Dong, Dawei Hu, Hui Zhou
Summary: In this study, true triaxial compression tests were conducted on granite specimens at different temperatures and under different intermediate principal stresses. The influences of temperature on crack initiation stress, crack damage stress, and peak strength of granite were analyzed. The failure characteristics of granite specimens under high temperature and true triaxial stress were investigated, and a Mogi-Coulomb failure criterion with temperature-dependent coefficients was proposed. This study provides new insights into the mechanical properties of rock under high temperature and true triaxial compression.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2023)
Article
Energy & Fuels
Jun Lu, Guangzhi Yin, Dongming Zhang, Xing Li, Gun Huang, Heng Gao
Summary: This study conducted experiments and analyzed CT scans to investigate the influence of different orientations and sizes of cavities on the strength and failure modes of rock samples. The results showed that the direction of the borehole and principal stress axis significantly affected the stability of the sandstone samples, while the intermediate principal stress played a significant role in the distribution of the damage zone.
GEOMECHANICS FOR ENERGY AND THE ENVIRONMENT
(2021)
Article
Engineering, Manufacturing
Yekai Yang, Chengqing Wu, Zhongxian Liu, Hai Zhang
Summary: This study presents an experimental investigation of the triaxial behavior of 3D-printing ultra-high performance fiber-reinforced concrete (3DP-UHPFRC) and compares it with mold-casting ultra-high performance fiber reinforced concrete (MC-UHPFRC). The results show that 3DP-UHPFRC has similar failure modes, mechanical properties, and failure criteria as MC-UHPFRC. Additionally, the fitting effect of the Mohr-Coulomb failure criterion on 3D-printing specimens without steel fiber is poor, while the Power-law and Willam-Warnke failure criteria are suitable for all 3D-printing specimens.
ADDITIVE MANUFACTURING
(2022)
Article
Geosciences, Multidisciplinary
Rongxi Shen, Zhoujie Gu, Zhentang Liu, Enlai Zhao, Zesheng Zang, Xin Zhou, Xiaoliang Li, Wei Liu, Xi Wang
Summary: A full understanding of the dynamic mechanical characteristics of coal samples under true triaxial conditions is crucial for preventing and controlling dynamic disasters in deep coal and rock. The study found that the transmission amplitude decreases as sigma 1 increases and increases with the impact velocity. The peak stress and absorbed energy of coal decrease with the increase in sigma 1 under true triaxial conditions. Under uniaxial and true triaxial conditions, the peak stress and absorbed energy of coal increase with the increase in impact velocity, and the stress change under true triaxial conditions is more sensitive to the dynamic load. Compared to uniaxial impact, the damage degree of coal samples under true triaxial conditions is lower. The fractal dimension of broken blocks increases linearly with the increase in sigma 1 and dynamic load, indicating an intensified degree of broken coal. This study effectively reveals the failure mechanism of coal under unequal static load and dynamic load.
NATURAL RESOURCES RESEARCH
(2023)
Article
Mining & Mineral Processing
Wei You, Feng Dai, Yi Liu, Hongbo Du, Ruochen Jiang
Summary: This study introduces a numerical servo triaxial Hopkinson bar (NSTHB) to investigate the dynamic responses of rocks under a true triaxial stress state. The results indicate that the increase in intermediate principal stress leads to an increase in dynamic strength and elastic modulus of rocks, while the dynamic elastic modulus remains independent of the dynamic strain rate. Additionally, the study shows that the intermediate principal stress significantly affects the dynamic failure modes of rocks.
INTERNATIONAL JOURNAL OF MINING SCIENCE AND TECHNOLOGY
(2021)
Article
Engineering, Mechanical
Yan Zhang, Zhaofeng Wang, Dingping Xu, Yaohui Gao, Yangyi Zhou, Liangjie Gu
Summary: Rock dilation is a nonlinear deformation and volume change that can be quantified by the dilation angle. This study has uncovered a new mechanism for true triaxial compressive fracturing, where dilatant fracturing is naturally mobilized by true triaxial stresses and significantly influenced by intermediate principal stress. A novel rock dilation angle (RDA) model is proposed to describe rock dilation behavior under true triaxial compression.
ENGINEERING FAILURE ANALYSIS
(2023)
Article
Engineering, Geological
Jun Zhao, Xia-Ting Feng, Chengxiang Yang, Benguo He, Mengfei Jiang
Summary: This paper investigates the stress relaxation behavior of Jinping marble under true triaxial stresses through true triaxial relaxation tests. The results show that the stress relaxation degree increases with the increase of axial strain before reaching the peak strength. Under unequal stresses, there is a difference in strain between two axial directions which increases with the increase of one axial stress.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2022)
Article
Engineering, Geological
Wenbin Lu, Zhende Zhu, Yanxin He, Xiangcheng Que
Summary: Columnar jointed basalt exhibits significant strength anisotropy, with different failure modes under various loading conditions. Analysis of its stability is crucial for excavated tunnel projects in such rock masses.
ROCK MECHANICS AND ROCK ENGINEERING
(2021)
Article
Engineering, Geological
Jun Lu, Heping Xie, Minghui Li, Cunbao Li, Mingzhong Gao, Delei Shang, Jianhua Li
Summary: This study investigates the mechanical behavior of sandstone under different microwave irradiation conditions through true triaxial tests. The results demonstrate that the strength of irradiated sandstone first increases and then decreases. The peak brittleness of the sandstone increases with an increase in stress. The stress difference induced by water vapor expansion and mineral thermal expansion is the main factor for microwave breaking water-bearing sandstone.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2022)
Article
Engineering, Environmental
Fan Xiao, Deyi Jiang, Fei Wu, Quanle Zou, Jie Chen, Bo Chen, Zhongguang Sun
Summary: The study found that high-temperature treatment weakens the density and P-wave velocity of sandstone specimens, leading to an increase in microcracks. As the temperature increases, the peak strength initially increases and then dramatically decreases, while the peak strain continues to increase. The changes in stress and strain at the unloading stage are negatively correlated with temperature.
BULLETIN OF ENGINEERING GEOLOGY AND THE ENVIRONMENT
(2021)
Article
Engineering, Geological
Ben-Guo He, Lei Wang, Xia-Ting Feng, Rong-Li Zhen
Summary: Most rockbursts are associated with jointed rock masses, as the energy stored inside the rock is prone to abruptly release at such discontinuities. Remote blasting at working faces can trigger brittle failure of jointed rocks. In this study, a testing system combining true-triaxial compression with dynamic disturbance is used to investigate the failure modes of cuboid jointed granite specimens. The results show that dynamic disturbance in different directions can significantly affect the peak strength and failure patterns of the specimens.
ROCK MECHANICS AND ROCK ENGINEERING
(2023)
Article
Engineering, Geological
Bangxiang Li, Weimeng Zhang, Yiguo Xue, Rui Kong, Weishen Zhu, Yuehao Yu, Yunjuan Chen
Summary: This study investigates the failure mechanism of sandstone through true triaxial tests and identifies the mechanisms of different areas on the fracture surface. The rock failure parameter S is defined to quantify the rock failure mechanism, with a larger S indicating a higher proportion of shear fracture in rock failure. The influences of sigma(2) and sigma(3) on rock failure mechanisms are also analyzed.
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
(2022)
Article
Mechanics
Chuanqi Zhu, Jun Zhao, Jiachao Xue, Feng Lin
Summary: This study investigates a three-dimensional crack growth model for rocks under stress, which can simulate crack growth and deformation characteristics. The research shows that the stress intensity factor at the crack tip increases with an increase in σ(1), promoting crack propagation, while it decreases with an increase in σ(2) and σ(3), inhibiting crack propagation.
ENGINEERING FRACTURE MECHANICS
(2022)
Article
Engineering, Geological
Chongyang Wang, Dongming Zhang, Beichen Yu, Shujian Li
Summary: The true triaxial loading-unloading tests of coal samples were conducted to analyze the deformation, seepage, damage, strength, and failure characteristics. The impact of gas pressure on permeability and yield conditions were investigated, and numerical simulation software was used to verify the true triaxial loading-unloading process. The results showed that the volumetric strain of the samples underwent a process of compaction, flatness, and re-compaction with time. The permeability was negatively correlated with volumetric strain. The damage factor and initial damage point of the samples increased with gas pressure, and the sample experienced different behaviors at different pressures.
ROCK MECHANICS AND ROCK ENGINEERING
(2023)
Article
Engineering, Mechanical
Xiao-Ping Zhou, Sen-Lin Peng, Jian-Zhi Zhang, Filippo Berto
Summary: The failure characteristics of rocks under true triaxial stress and the cracking mechanism are not fully understood. This study conducted true triaxial compression tests on flawed sandstone specimens to explore the effects of microstructure and pre-existing flaws on cracking characteristics. It was found that microstructure and pre-existing flaws collectively affect cracking characteristics and the interaction between coarse grains in coarse sandstone contributes to its strength. However, fine sandstone shows less microcrack clustering and weaker interaction between microcracks, leading to less micro-shear cracking.
THEORETICAL AND APPLIED FRACTURE MECHANICS
(2021)